Infectious Diseases

Researchers have found for the first time that COVID infection has crossed the placenta and caused brain damage in two newborns, according to a study published online today in Pediatrics .

One of the infants died at 13 months and the other remained in hospice care at time of manuscript submission.

Lead author Merline Benny, MD, with the division of neonatology, department of pediatrics at University of Miami, and colleagues briefed reporters today ahead of the release.

Zelda Calvert

“This is a first,” said senior author Shahnaz Duara, MD, medical director of the Neonatal Intensive Care Unit at Holtz Children’s Hospital, Miami, explaining it is the first study to confirm cross-placental SARS-CoV-2 transmission leading to brain injury in a newborn.
 

Both infants negative for the virus at birth

The two infants were admitted in the early days of the pandemic in the Delta wave to the neonatal ICU at Holtz Children’s Hospital at University of Miami/Jackson Memorial Medical Center.

Both infants tested negative for the virus at birth, but had significantly elevated SARS-CoV-2 antibodies in their blood, indicating that either antibodies crossed the placenta, or the virus crossed and the immune response was the baby’s.

Dr. Benny explained that the researchers have seen, to this point, more than 700 mother/infant pairs in whom the mother tested positive for COVID in Jackson hospital.

Most who tested positive for COVID were asymptomatic and most of the mothers and infants left the hospital without complications.

“However, (these) two babies had a very unusual clinical picture,” Dr. Benny said.

Those infants were born to mothers who became COVID positive in the second trimester and delivered a few weeks later.

Seizures started on day 1 of life

The babies began to seize from the first day of life. They had profound low tone (hypotonia) in their clinical exam, Dr. Benny explained.

“We had absolutely no good explanation for the early seizures and the degree of brain injury we saw,” Dr. Duara said.

Dr. Benny said that as their bodies grew, they had very small head circumference. Unlike some babies born with the Zika virus, these babies were not microcephalic at birth. Brain imaging on the two babies indicated significant brain atrophy, and neurodevelopment exams showed significant delay.

Discussions began with the center’s multidisciplinary team including neurologists, pathologists, neuroradiologists, and obstetricians who cared for both the mothers and the babies.

The experts examined the placentas and found some characteristic COVID changes and presence of the COVID virus. This was accompanied by increased markers for inflammation and a severe reduction in a hormone critical for placental health and brain development.

Examining the infant’s autopsy findings further raised suspicions of maternal transmission, something that had not been documented before.

Coauthor Ali G. Saad, MD, pediatric and perinatal pathology director at Miami, said, “I have seen literally thousands of brains in autopsies over the last 14 years, and this was the most dramatic case of leukoencephalopathy or loss of white matter in a patient with no significant reason. That’s what triggered the investigation.”
 

Mothers had very different presentations

Coauthor Michael J. Paidas, MD, with the department of obstetrics, gynecology, and reproductive sciences at Miami, pointed out that the circumstances of the two mothers, who were in their 20s, were very different.

One mother delivered at 32 weeks and had a very severe COVID presentation and spent a month in the intensive care unit. The team decided to deliver the child to save the mother, Dr. Paidas said.

In contrast, the other mother had asymptomatic COVID infection in the second trimester and delivered at full term.

He said one of the early suspicions in the babies’ presentations was hypoxic ischemic encephalopathy. “But it wasn’t lack of blood flow to the placenta that caused this,” he said. “As best we can tell, it was the viral infection.”
 

Instances are rare

The researchers emphasized that these instances are rare and have not been seen before or since the period of this study to their knowledge.

Dr. Duara said, “This is something we want to alert the medical community to more than the general public. We do not want the lay public to be panicked. We’re trying to understand what made these two pregnancies different, so we can direct research towards protecting vulnerable babies.”

Previous data have indicated a relatively benign status in infants who test negative for the COVID virus after birth. Dr. Benny added that COVID vaccination has been found safe in pregnancy and both vaccination and breastfeeding can help passage of antibodies to the infant and help protect the baby. Because these cases happened in the early days of the pandemic, no vaccines were available.

Dr. Paidas received funding from BioIncept to study hypoxic-ischemic encephalopathy with Preimplantation Factor, is a scientific advisory board member, and has stock options. Dr. Paidas and coauthor Dr. Jayakumar are coinventors of SPIKENET, University of Miami, patent pending 2023. The other authors have no conflicts of interest to disclose.

Researchers have found for the first time that COVID infection has crossed the placenta and caused brain damage in two newborns, according to a study published online today in Pediatrics .

One of the infants died at 13 months and the other remained in hospice care at time of manuscript submission.

Lead author Merline Benny, MD, with the division of neonatology, department of pediatrics at University of Miami, and colleagues briefed reporters today ahead of the release.

Zelda Calvert

“This is a first,” said senior author Shahnaz Duara, MD, medical director of the Neonatal Intensive Care Unit at Holtz Children’s Hospital, Miami, explaining it is the first study to confirm cross-placental SARS-CoV-2 transmission leading to brain injury in a newborn.
 

Both infants negative for the virus at birth

The two infants were admitted in the early days of the pandemic in the Delta wave to the neonatal ICU at Holtz Children’s Hospital at University of Miami/Jackson Memorial Medical Center.

Both infants tested negative for the virus at birth, but had significantly elevated SARS-CoV-2 antibodies in their blood, indicating that either antibodies crossed the placenta, or the virus crossed and the immune response was the baby’s.

Dr. Benny explained that the researchers have seen, to this point, more than 700 mother/infant pairs in whom the mother tested positive for COVID in Jackson hospital.

Most who tested positive for COVID were asymptomatic and most of the mothers and infants left the hospital without complications.

“However, (these) two babies had a very unusual clinical picture,” Dr. Benny said.

Those infants were born to mothers who became COVID positive in the second trimester and delivered a few weeks later.

Seizures started on day 1 of life

The babies began to seize from the first day of life. They had profound low tone (hypotonia) in their clinical exam, Dr. Benny explained.

“We had absolutely no good explanation for the early seizures and the degree of brain injury we saw,” Dr. Duara said.

Dr. Benny said that as their bodies grew, they had very small head circumference. Unlike some babies born with the Zika virus, these babies were not microcephalic at birth. Brain imaging on the two babies indicated significant brain atrophy, and neurodevelopment exams showed significant delay.

Discussions began with the center’s multidisciplinary team including neurologists, pathologists, neuroradiologists, and obstetricians who cared for both the mothers and the babies.

The experts examined the placentas and found some characteristic COVID changes and presence of the COVID virus. This was accompanied by increased markers for inflammation and a severe reduction in a hormone critical for placental health and brain development.

Examining the infant’s autopsy findings further raised suspicions of maternal transmission, something that had not been documented before.

Coauthor Ali G. Saad, MD, pediatric and perinatal pathology director at Miami, said, “I have seen literally thousands of brains in autopsies over the last 14 years, and this was the most dramatic case of leukoencephalopathy or loss of white matter in a patient with no significant reason. That’s what triggered the investigation.”
 

Mothers had very different presentations

Coauthor Michael J. Paidas, MD, with the department of obstetrics, gynecology, and reproductive sciences at Miami, pointed out that the circumstances of the two mothers, who were in their 20s, were very different.

One mother delivered at 32 weeks and had a very severe COVID presentation and spent a month in the intensive care unit. The team decided to deliver the child to save the mother, Dr. Paidas said.

In contrast, the other mother had asymptomatic COVID infection in the second trimester and delivered at full term.

He said one of the early suspicions in the babies’ presentations was hypoxic ischemic encephalopathy. “But it wasn’t lack of blood flow to the placenta that caused this,” he said. “As best we can tell, it was the viral infection.”
 

Instances are rare

The researchers emphasized that these instances are rare and have not been seen before or since the period of this study to their knowledge.

Dr. Duara said, “This is something we want to alert the medical community to more than the general public. We do not want the lay public to be panicked. We’re trying to understand what made these two pregnancies different, so we can direct research towards protecting vulnerable babies.”

Previous data have indicated a relatively benign status in infants who test negative for the COVID virus after birth. Dr. Benny added that COVID vaccination has been found safe in pregnancy and both vaccination and breastfeeding can help passage of antibodies to the infant and help protect the baby. Because these cases happened in the early days of the pandemic, no vaccines were available.

Dr. Paidas received funding from BioIncept to study hypoxic-ischemic encephalopathy with Preimplantation Factor, is a scientific advisory board member, and has stock options. Dr. Paidas and coauthor Dr. Jayakumar are coinventors of SPIKENET, University of Miami, patent pending 2023. The other authors have no conflicts of interest to disclose.

Researchers have found for the first time that COVID infection has crossed the placenta and caused brain damage in two newborns, according to a study published online today in Pediatrics .

One of the infants died at 13 months and the other remained in hospice care at time of manuscript submission.

Lead author Merline Benny, MD, with the division of neonatology, department of pediatrics at University of Miami, and colleagues briefed reporters today ahead of the release.

Zelda Calvert

“This is a first,” said senior author Shahnaz Duara, MD, medical director of the Neonatal Intensive Care Unit at Holtz Children’s Hospital, Miami, explaining it is the first study to confirm cross-placental SARS-CoV-2 transmission leading to brain injury in a newborn.
 

Both infants negative for the virus at birth

The two infants were admitted in the early days of the pandemic in the Delta wave to the neonatal ICU at Holtz Children’s Hospital at University of Miami/Jackson Memorial Medical Center.

Both infants tested negative for the virus at birth, but had significantly elevated SARS-CoV-2 antibodies in their blood, indicating that either antibodies crossed the placenta, or the virus crossed and the immune response was the baby’s.

Dr. Benny explained that the researchers have seen, to this point, more than 700 mother/infant pairs in whom the mother tested positive for COVID in Jackson hospital.

Most who tested positive for COVID were asymptomatic and most of the mothers and infants left the hospital without complications.

“However, (these) two babies had a very unusual clinical picture,” Dr. Benny said.

Those infants were born to mothers who became COVID positive in the second trimester and delivered a few weeks later.

Seizures started on day 1 of life

The babies began to seize from the first day of life. They had profound low tone (hypotonia) in their clinical exam, Dr. Benny explained.

“We had absolutely no good explanation for the early seizures and the degree of brain injury we saw,” Dr. Duara said.

Dr. Benny said that as their bodies grew, they had very small head circumference. Unlike some babies born with the Zika virus, these babies were not microcephalic at birth. Brain imaging on the two babies indicated significant brain atrophy, and neurodevelopment exams showed significant delay.

Discussions began with the center’s multidisciplinary team including neurologists, pathologists, neuroradiologists, and obstetricians who cared for both the mothers and the babies.

The experts examined the placentas and found some characteristic COVID changes and presence of the COVID virus. This was accompanied by increased markers for inflammation and a severe reduction in a hormone critical for placental health and brain development.

Examining the infant’s autopsy findings further raised suspicions of maternal transmission, something that had not been documented before.

Coauthor Ali G. Saad, MD, pediatric and perinatal pathology director at Miami, said, “I have seen literally thousands of brains in autopsies over the last 14 years, and this was the most dramatic case of leukoencephalopathy or loss of white matter in a patient with no significant reason. That’s what triggered the investigation.”
 

Mothers had very different presentations

Coauthor Michael J. Paidas, MD, with the department of obstetrics, gynecology, and reproductive sciences at Miami, pointed out that the circumstances of the two mothers, who were in their 20s, were very different.

One mother delivered at 32 weeks and had a very severe COVID presentation and spent a month in the intensive care unit. The team decided to deliver the child to save the mother, Dr. Paidas said.

In contrast, the other mother had asymptomatic COVID infection in the second trimester and delivered at full term.

He said one of the early suspicions in the babies’ presentations was hypoxic ischemic encephalopathy. “But it wasn’t lack of blood flow to the placenta that caused this,” he said. “As best we can tell, it was the viral infection.”
 

Instances are rare

The researchers emphasized that these instances are rare and have not been seen before or since the period of this study to their knowledge.

Dr. Duara said, “This is something we want to alert the medical community to more than the general public. We do not want the lay public to be panicked. We’re trying to understand what made these two pregnancies different, so we can direct research towards protecting vulnerable babies.”

Previous data have indicated a relatively benign status in infants who test negative for the COVID virus after birth. Dr. Benny added that COVID vaccination has been found safe in pregnancy and both vaccination and breastfeeding can help passage of antibodies to the infant and help protect the baby. Because these cases happened in the early days of the pandemic, no vaccines were available.

Dr. Paidas received funding from BioIncept to study hypoxic-ischemic encephalopathy with Preimplantation Factor, is a scientific advisory board member, and has stock options. Dr. Paidas and coauthor Dr. Jayakumar are coinventors of SPIKENET, University of Miami, patent pending 2023. The other authors have no conflicts of interest to disclose.

Investigators found that simultaneous infection with adeno-associated virus type 2 (AAV2) and certain other viruses is associated with the outbreak of mysterious pediatric hepatitis cases worldwide.

Coinfection with AAV2 and a human adenovirus (HAdV), in particular, appears to leave some children more vulnerable to this acute hepatitis of unknown origin, researchers reported in three studies published online in Nature. Coinfection with Epstein-Barr virus (EBV), herpes, and enterovirus also were found. Adeno-associated viruses are not considered pathogenic on their own and require a “helper” virus for productive infection.

“I am quite confident that we have identified the key viruses involved because we used a comprehensive metagenomic sequencing approach to look for potential infections from any virus or non-viral pathogen,” Charles Chiu, MD, PhD, senior author and professor of laboratory medicine and medicine/infectious diseases at the University of California, San Francisco, said in an interview.

Dr. Chiu and colleagues propose that lockdowns and social isolation during the COVID-19 pandemic left more children susceptible. A major aspect of immunity in childhood is the adaptive immune response – both cell-mediated and humoral – shaped in part by exposure to viruses and other pathogens early in life, Dr. Chiu said.

“Due to COVID-19, a large population of children did not experience this, so it is possible once restrictions were lifted, they were suddenly exposed over a short period of time to multiple viruses that, in a poorly trained immune system, would have increased their risk of developing severe disease,” he said.

This theory has been popular, especially because cases of unexplained acute hepatitis peaked during the height of the COVID-19 pandemic when isolation was common, William F. Balistreri, MD, who was not affiliated with the study, told this news organization. Dr. Balistreri is professor of pediatrics and director emeritus of the Pediatric Liver Care Center at Cincinnati Children’s Hospital Medical Center.
 

Identifying the culprits

Determining what factors might be involved was the main aim of the etiology study by Dr. Chiu and colleagues published online  in Nature.

The journal simultaneously published a genomic study confirming the presence of AAV2 and other suspected viruses and a genomic and laboratory study further corroborating the results.

More than 1,000 children worldwide had been diagnosed with unexplained acute pediatric hepatitis as of August 2022. In the United States, there have been 358 cases, including 22 in which the child required a liver transplant and 13 in which the child died.

This new form of hepatitis, first detected in October 2021, does not fit into existing classifications of types A through E, so some researchers refer to the condition as acute non–A-E hepatitis of unknown etiology.

The investigators started with an important clue based on previous research: the role adenovirus might play. Dr. Chiu and colleagues assessed 27 blood, stool, and other samples from 16 affected children who each previously tested positive for adenoviruses. The researchers included cases of the condition identified up until May 22, 2022. The median age was 3 years, and approximately half were boys.

They compared viruses present in these children with those in 113 controls without the mysterious hepatitis. The control group consisted of 15 children who were hospitalized with a nonhepatitis inflammatory condition, 27 with a noninflammatory condition, 30 with acute hepatitis of known origin, 12 with acute gastroenteritis and an HAdV-positive stool sample, and 11 with acute gastroenteritis and an HAdV-negative stool sample, as well as 18 blood donors. The median age was 7 years.

The researchers assessed samples using multiple technologies, including metagenomic sequencing, tiling multiplex polymerase chain reaction (PCR) amplicon sequencing, metagenomic sequencing with probe capture viral enrichment, and virus-specific PCR. Many of these advanced techniques were not even available 5-10 years ago, Dr. Chiu said.
 

Key findings

Blood samples were available for 14 of the 16 children with acute hepatitis of unknown origin. Among this study group, AAV2 was found in 13 (93%). No other adeno-associated viruses were found. HAdV was detected in all 14 children: HAdV-41 in 11 children and HAdV-40, HAdV-2, and an untypeable strain in one child each. This finding was not intuitive because HAdVs are not commonly associated with hepatitis, according to the study.

AAV2 was much less common in the control group. For example, it was found in none of the children with hepatitis of known origin and in only four children (3.5%) with acute gastroenteritis and HAdV-positive stool. Of note, neither AAV2 nor HAdV-41 was detected among the 30 pediatric controls with acute hepatitis of defined etiology nor 42 of the hospitalized children without hepatitis, the researchers wrote.

In the search for other viruses in the study group, metagenomic sequencing detected EBV, also known as human herpesvirus (HHV)–4, in two children, cytomegalovirus (CMV) in one child, and HAdV type C in one child.

Analysis of whole blood revealed enterovirus A71 in one patient. HAdV type C also was detected in one child on the basis of a nasopharyngeal swab, and picobirnavirus was found in a stool sample from another patient.

Researchers conducted virus-specific PCR tests on both patient groups to identify additional viruses that may be associated with the unexplained acute hepatitis. EBV/HHV-4 was detected in 11 children (79%) in the study group vs. in 1 child (0.88%) in the control group. HHV-6 was detected in seven children (50%) in the study group, compared with one case in the control group. CMV was not detected in any of the children in the study group versus vs. two children (1.8%) in the control group.

“Although we found significant differences in the relative proportions of EBV and HHV-6 in cases compared to controls, we do not believe that these viruses are the primary cause of acute severe hepatitis,” the researchers wrote. The viral load of the two herpes viruses were very low, so the positive results could represent integrated proviral DNA rather than bona fide low-level herpesvirus. In addition, herpesvirus can be reactivated by an inflammatory condition.

“Nevertheless, it is striking that among the 16 cases (in the study group), dual, triple, or quadruple infections with AAV2, adenovirus, and one or both herpesviruses were detected in whole blood from at least 12 cases (75%),” the researchers wrote.
 

Management of suspected hepatitis

The study’s key messages for parents and health care providers “are awareness and reassurance,” Dr. Balistreri said in an interview.

Vigilance also is warranted if a child develops prodromal symptoms including respiratory and/or gastrointestinal signs such as nausea, vomiting, diarrhea, and abdomen pain, he said. If jaundice or scleral icterus is noted, then hepatitis should be suspected.

Some patients need hospitalization and quickly recover. In very rare instances, the inflammation may progress to liver failure and transplantation, Dr. Balistreri said.

“Reassurance is based on the good news that most children with acute hepatitis get better. If a case arises, it is good practice to keep the child well hydrated, offer a normal diet, and avoid medications that may be cleared by the liver,” Dr. Balistreri added.

“Of course, COVID-19 vaccination is strongly suggested,” he said.

Some existing treatments could help against unexplained acute hepatitis, Dr. Chiu said. “The findings suggest that antiviral therapy might be effective in these cases.”

Cidofovir can be effective against adenovirus, according to a report in The Lancet . Similarly, ganciclovir or valganciclovir may have activity against EBV/HHV-4 or HHV-6, Dr. Chiu said. “However, antiviral therapy is not available for AAV2.”

The three studies published in Nature “offer compelling evidence, from disparate centers, of a linkage of outbreak cases to infection by AAV2,” Dr. Balistreri said. The studies also suggest that liver injury was related to abnormal immune responses. This is an important clinical distinction, indicating a potential therapeutic approach to future cases – immunosuppression rather than anti-adenoviral agents, he said.

“We await further studies of this important concept,” Dr. Balistreri said.

Many unanswered questions remain about the condition’s etiology, he added. Is there a synergy or shared susceptibility related to SARS-CoV-2? Is the COVID-19 virus helping to trigger these infections, or does it increase the risk once infected? Also, are other epigenetic factors or viruses involved?
 

Moving forward

The next steps in the research could go beyond identifying presence of these different viruses and determining which one(s) are contributing the most to the acute pediatric hepatitis, Dr. Chiu said.

The researchers also would like to test early results from the United Kingdom that identified a potential association of acute severe hepatitis with the presence of human leukocyte antigen genotype DRB1*04:01, he added.

They also might investigate other unintended potential clinical consequences of the COVID-19 pandemic, including long COVID and resurgence of infections from other viruses, such as respiratory syncytial virus, influenza, and enterovirus D68.

The study was supported by the Centers for Disease Control and Prevention, the National Institutes of Health, the Department of Homeland Security, and other grants. Dr. Chiu is a founder of Delve Bio and on the scientific advisory board for Delve Bio, Mammoth Biosciences, BiomeSense, and Poppy Health. Dr. Balistreri had no relevant disclosures.
 

A version of this article first appeared on Medscape.com.

Investigators found that simultaneous infection with adeno-associated virus type 2 (AAV2) and certain other viruses is associated with the outbreak of mysterious pediatric hepatitis cases worldwide.

Coinfection with AAV2 and a human adenovirus (HAdV), in particular, appears to leave some children more vulnerable to this acute hepatitis of unknown origin, researchers reported in three studies published online in Nature. Coinfection with Epstein-Barr virus (EBV), herpes, and enterovirus also were found. Adeno-associated viruses are not considered pathogenic on their own and require a “helper” virus for productive infection.

“I am quite confident that we have identified the key viruses involved because we used a comprehensive metagenomic sequencing approach to look for potential infections from any virus or non-viral pathogen,” Charles Chiu, MD, PhD, senior author and professor of laboratory medicine and medicine/infectious diseases at the University of California, San Francisco, said in an interview.

Dr. Chiu and colleagues propose that lockdowns and social isolation during the COVID-19 pandemic left more children susceptible. A major aspect of immunity in childhood is the adaptive immune response – both cell-mediated and humoral – shaped in part by exposure to viruses and other pathogens early in life, Dr. Chiu said.

“Due to COVID-19, a large population of children did not experience this, so it is possible once restrictions were lifted, they were suddenly exposed over a short period of time to multiple viruses that, in a poorly trained immune system, would have increased their risk of developing severe disease,” he said.

This theory has been popular, especially because cases of unexplained acute hepatitis peaked during the height of the COVID-19 pandemic when isolation was common, William F. Balistreri, MD, who was not affiliated with the study, told this news organization. Dr. Balistreri is professor of pediatrics and director emeritus of the Pediatric Liver Care Center at Cincinnati Children’s Hospital Medical Center.
 

Identifying the culprits

Determining what factors might be involved was the main aim of the etiology study by Dr. Chiu and colleagues published online  in Nature.

The journal simultaneously published a genomic study confirming the presence of AAV2 and other suspected viruses and a genomic and laboratory study further corroborating the results.

More than 1,000 children worldwide had been diagnosed with unexplained acute pediatric hepatitis as of August 2022. In the United States, there have been 358 cases, including 22 in which the child required a liver transplant and 13 in which the child died.

This new form of hepatitis, first detected in October 2021, does not fit into existing classifications of types A through E, so some researchers refer to the condition as acute non–A-E hepatitis of unknown etiology.

The investigators started with an important clue based on previous research: the role adenovirus might play. Dr. Chiu and colleagues assessed 27 blood, stool, and other samples from 16 affected children who each previously tested positive for adenoviruses. The researchers included cases of the condition identified up until May 22, 2022. The median age was 3 years, and approximately half were boys.

They compared viruses present in these children with those in 113 controls without the mysterious hepatitis. The control group consisted of 15 children who were hospitalized with a nonhepatitis inflammatory condition, 27 with a noninflammatory condition, 30 with acute hepatitis of known origin, 12 with acute gastroenteritis and an HAdV-positive stool sample, and 11 with acute gastroenteritis and an HAdV-negative stool sample, as well as 18 blood donors. The median age was 7 years.

The researchers assessed samples using multiple technologies, including metagenomic sequencing, tiling multiplex polymerase chain reaction (PCR) amplicon sequencing, metagenomic sequencing with probe capture viral enrichment, and virus-specific PCR. Many of these advanced techniques were not even available 5-10 years ago, Dr. Chiu said.
 

Key findings

Blood samples were available for 14 of the 16 children with acute hepatitis of unknown origin. Among this study group, AAV2 was found in 13 (93%). No other adeno-associated viruses were found. HAdV was detected in all 14 children: HAdV-41 in 11 children and HAdV-40, HAdV-2, and an untypeable strain in one child each. This finding was not intuitive because HAdVs are not commonly associated with hepatitis, according to the study.

AAV2 was much less common in the control group. For example, it was found in none of the children with hepatitis of known origin and in only four children (3.5%) with acute gastroenteritis and HAdV-positive stool. Of note, neither AAV2 nor HAdV-41 was detected among the 30 pediatric controls with acute hepatitis of defined etiology nor 42 of the hospitalized children without hepatitis, the researchers wrote.

In the search for other viruses in the study group, metagenomic sequencing detected EBV, also known as human herpesvirus (HHV)–4, in two children, cytomegalovirus (CMV) in one child, and HAdV type C in one child.

Analysis of whole blood revealed enterovirus A71 in one patient. HAdV type C also was detected in one child on the basis of a nasopharyngeal swab, and picobirnavirus was found in a stool sample from another patient.

Researchers conducted virus-specific PCR tests on both patient groups to identify additional viruses that may be associated with the unexplained acute hepatitis. EBV/HHV-4 was detected in 11 children (79%) in the study group vs. in 1 child (0.88%) in the control group. HHV-6 was detected in seven children (50%) in the study group, compared with one case in the control group. CMV was not detected in any of the children in the study group versus vs. two children (1.8%) in the control group.

“Although we found significant differences in the relative proportions of EBV and HHV-6 in cases compared to controls, we do not believe that these viruses are the primary cause of acute severe hepatitis,” the researchers wrote. The viral load of the two herpes viruses were very low, so the positive results could represent integrated proviral DNA rather than bona fide low-level herpesvirus. In addition, herpesvirus can be reactivated by an inflammatory condition.

“Nevertheless, it is striking that among the 16 cases (in the study group), dual, triple, or quadruple infections with AAV2, adenovirus, and one or both herpesviruses were detected in whole blood from at least 12 cases (75%),” the researchers wrote.
 

Management of suspected hepatitis

The study’s key messages for parents and health care providers “are awareness and reassurance,” Dr. Balistreri said in an interview.

Vigilance also is warranted if a child develops prodromal symptoms including respiratory and/or gastrointestinal signs such as nausea, vomiting, diarrhea, and abdomen pain, he said. If jaundice or scleral icterus is noted, then hepatitis should be suspected.

Some patients need hospitalization and quickly recover. In very rare instances, the inflammation may progress to liver failure and transplantation, Dr. Balistreri said.

“Reassurance is based on the good news that most children with acute hepatitis get better. If a case arises, it is good practice to keep the child well hydrated, offer a normal diet, and avoid medications that may be cleared by the liver,” Dr. Balistreri added.

“Of course, COVID-19 vaccination is strongly suggested,” he said.

Some existing treatments could help against unexplained acute hepatitis, Dr. Chiu said. “The findings suggest that antiviral therapy might be effective in these cases.”

Cidofovir can be effective against adenovirus, according to a report in The Lancet . Similarly, ganciclovir or valganciclovir may have activity against EBV/HHV-4 or HHV-6, Dr. Chiu said. “However, antiviral therapy is not available for AAV2.”

The three studies published in Nature “offer compelling evidence, from disparate centers, of a linkage of outbreak cases to infection by AAV2,” Dr. Balistreri said. The studies also suggest that liver injury was related to abnormal immune responses. This is an important clinical distinction, indicating a potential therapeutic approach to future cases – immunosuppression rather than anti-adenoviral agents, he said.

“We await further studies of this important concept,” Dr. Balistreri said.

Many unanswered questions remain about the condition’s etiology, he added. Is there a synergy or shared susceptibility related to SARS-CoV-2? Is the COVID-19 virus helping to trigger these infections, or does it increase the risk once infected? Also, are other epigenetic factors or viruses involved?
 

Moving forward

The next steps in the research could go beyond identifying presence of these different viruses and determining which one(s) are contributing the most to the acute pediatric hepatitis, Dr. Chiu said.

The researchers also would like to test early results from the United Kingdom that identified a potential association of acute severe hepatitis with the presence of human leukocyte antigen genotype DRB1*04:01, he added.

They also might investigate other unintended potential clinical consequences of the COVID-19 pandemic, including long COVID and resurgence of infections from other viruses, such as respiratory syncytial virus, influenza, and enterovirus D68.

The study was supported by the Centers for Disease Control and Prevention, the National Institutes of Health, the Department of Homeland Security, and other grants. Dr. Chiu is a founder of Delve Bio and on the scientific advisory board for Delve Bio, Mammoth Biosciences, BiomeSense, and Poppy Health. Dr. Balistreri had no relevant disclosures.
 

A version of this article first appeared on Medscape.com.

Investigators found that simultaneous infection with adeno-associated virus type 2 (AAV2) and certain other viruses is associated with the outbreak of mysterious pediatric hepatitis cases worldwide.

Coinfection with AAV2 and a human adenovirus (HAdV), in particular, appears to leave some children more vulnerable to this acute hepatitis of unknown origin, researchers reported in three studies published online in Nature. Coinfection with Epstein-Barr virus (EBV), herpes, and enterovirus also were found. Adeno-associated viruses are not considered pathogenic on their own and require a “helper” virus for productive infection.

“I am quite confident that we have identified the key viruses involved because we used a comprehensive metagenomic sequencing approach to look for potential infections from any virus or non-viral pathogen,” Charles Chiu, MD, PhD, senior author and professor of laboratory medicine and medicine/infectious diseases at the University of California, San Francisco, said in an interview.

Dr. Chiu and colleagues propose that lockdowns and social isolation during the COVID-19 pandemic left more children susceptible. A major aspect of immunity in childhood is the adaptive immune response – both cell-mediated and humoral – shaped in part by exposure to viruses and other pathogens early in life, Dr. Chiu said.

“Due to COVID-19, a large population of children did not experience this, so it is possible once restrictions were lifted, they were suddenly exposed over a short period of time to multiple viruses that, in a poorly trained immune system, would have increased their risk of developing severe disease,” he said.

This theory has been popular, especially because cases of unexplained acute hepatitis peaked during the height of the COVID-19 pandemic when isolation was common, William F. Balistreri, MD, who was not affiliated with the study, told this news organization. Dr. Balistreri is professor of pediatrics and director emeritus of the Pediatric Liver Care Center at Cincinnati Children’s Hospital Medical Center.
 

Identifying the culprits

Determining what factors might be involved was the main aim of the etiology study by Dr. Chiu and colleagues published online  in Nature.

The journal simultaneously published a genomic study confirming the presence of AAV2 and other suspected viruses and a genomic and laboratory study further corroborating the results.

More than 1,000 children worldwide had been diagnosed with unexplained acute pediatric hepatitis as of August 2022. In the United States, there have been 358 cases, including 22 in which the child required a liver transplant and 13 in which the child died.

This new form of hepatitis, first detected in October 2021, does not fit into existing classifications of types A through E, so some researchers refer to the condition as acute non–A-E hepatitis of unknown etiology.

The investigators started with an important clue based on previous research: the role adenovirus might play. Dr. Chiu and colleagues assessed 27 blood, stool, and other samples from 16 affected children who each previously tested positive for adenoviruses. The researchers included cases of the condition identified up until May 22, 2022. The median age was 3 years, and approximately half were boys.

They compared viruses present in these children with those in 113 controls without the mysterious hepatitis. The control group consisted of 15 children who were hospitalized with a nonhepatitis inflammatory condition, 27 with a noninflammatory condition, 30 with acute hepatitis of known origin, 12 with acute gastroenteritis and an HAdV-positive stool sample, and 11 with acute gastroenteritis and an HAdV-negative stool sample, as well as 18 blood donors. The median age was 7 years.

The researchers assessed samples using multiple technologies, including metagenomic sequencing, tiling multiplex polymerase chain reaction (PCR) amplicon sequencing, metagenomic sequencing with probe capture viral enrichment, and virus-specific PCR. Many of these advanced techniques were not even available 5-10 years ago, Dr. Chiu said.
 

Key findings

Blood samples were available for 14 of the 16 children with acute hepatitis of unknown origin. Among this study group, AAV2 was found in 13 (93%). No other adeno-associated viruses were found. HAdV was detected in all 14 children: HAdV-41 in 11 children and HAdV-40, HAdV-2, and an untypeable strain in one child each. This finding was not intuitive because HAdVs are not commonly associated with hepatitis, according to the study.

AAV2 was much less common in the control group. For example, it was found in none of the children with hepatitis of known origin and in only four children (3.5%) with acute gastroenteritis and HAdV-positive stool. Of note, neither AAV2 nor HAdV-41 was detected among the 30 pediatric controls with acute hepatitis of defined etiology nor 42 of the hospitalized children without hepatitis, the researchers wrote.

In the search for other viruses in the study group, metagenomic sequencing detected EBV, also known as human herpesvirus (HHV)–4, in two children, cytomegalovirus (CMV) in one child, and HAdV type C in one child.

Analysis of whole blood revealed enterovirus A71 in one patient. HAdV type C also was detected in one child on the basis of a nasopharyngeal swab, and picobirnavirus was found in a stool sample from another patient.

Researchers conducted virus-specific PCR tests on both patient groups to identify additional viruses that may be associated with the unexplained acute hepatitis. EBV/HHV-4 was detected in 11 children (79%) in the study group vs. in 1 child (0.88%) in the control group. HHV-6 was detected in seven children (50%) in the study group, compared with one case in the control group. CMV was not detected in any of the children in the study group versus vs. two children (1.8%) in the control group.

“Although we found significant differences in the relative proportions of EBV and HHV-6 in cases compared to controls, we do not believe that these viruses are the primary cause of acute severe hepatitis,” the researchers wrote. The viral load of the two herpes viruses were very low, so the positive results could represent integrated proviral DNA rather than bona fide low-level herpesvirus. In addition, herpesvirus can be reactivated by an inflammatory condition.

“Nevertheless, it is striking that among the 16 cases (in the study group), dual, triple, or quadruple infections with AAV2, adenovirus, and one or both herpesviruses were detected in whole blood from at least 12 cases (75%),” the researchers wrote.
 

Management of suspected hepatitis

The study’s key messages for parents and health care providers “are awareness and reassurance,” Dr. Balistreri said in an interview.

Vigilance also is warranted if a child develops prodromal symptoms including respiratory and/or gastrointestinal signs such as nausea, vomiting, diarrhea, and abdomen pain, he said. If jaundice or scleral icterus is noted, then hepatitis should be suspected.

Some patients need hospitalization and quickly recover. In very rare instances, the inflammation may progress to liver failure and transplantation, Dr. Balistreri said.

“Reassurance is based on the good news that most children with acute hepatitis get better. If a case arises, it is good practice to keep the child well hydrated, offer a normal diet, and avoid medications that may be cleared by the liver,” Dr. Balistreri added.

“Of course, COVID-19 vaccination is strongly suggested,” he said.

Some existing treatments could help against unexplained acute hepatitis, Dr. Chiu said. “The findings suggest that antiviral therapy might be effective in these cases.”

Cidofovir can be effective against adenovirus, according to a report in The Lancet . Similarly, ganciclovir or valganciclovir may have activity against EBV/HHV-4 or HHV-6, Dr. Chiu said. “However, antiviral therapy is not available for AAV2.”

The three studies published in Nature “offer compelling evidence, from disparate centers, of a linkage of outbreak cases to infection by AAV2,” Dr. Balistreri said. The studies also suggest that liver injury was related to abnormal immune responses. This is an important clinical distinction, indicating a potential therapeutic approach to future cases – immunosuppression rather than anti-adenoviral agents, he said.

“We await further studies of this important concept,” Dr. Balistreri said.

Many unanswered questions remain about the condition’s etiology, he added. Is there a synergy or shared susceptibility related to SARS-CoV-2? Is the COVID-19 virus helping to trigger these infections, or does it increase the risk once infected? Also, are other epigenetic factors or viruses involved?
 

Moving forward

The next steps in the research could go beyond identifying presence of these different viruses and determining which one(s) are contributing the most to the acute pediatric hepatitis, Dr. Chiu said.

The researchers also would like to test early results from the United Kingdom that identified a potential association of acute severe hepatitis with the presence of human leukocyte antigen genotype DRB1*04:01, he added.

They also might investigate other unintended potential clinical consequences of the COVID-19 pandemic, including long COVID and resurgence of infections from other viruses, such as respiratory syncytial virus, influenza, and enterovirus D68.

The study was supported by the Centers for Disease Control and Prevention, the National Institutes of Health, the Department of Homeland Security, and other grants. Dr. Chiu is a founder of Delve Bio and on the scientific advisory board for Delve Bio, Mammoth Biosciences, BiomeSense, and Poppy Health. Dr. Balistreri had no relevant disclosures.
 

A version of this article first appeared on Medscape.com.

Contaminated, deadly, and blindness-causing eyedrops that were recalled earlier this year were made in India at a factory not inspected by the U.S. Food and Drug Administration, according to a new report. 

Scientists are concerned that the once-rare treatment-resistant bacteria found in the eyedrops can spread person-to-person, posing a risk of becoming a recurrent problem in the United States, The New York Times reported.

In January, EzriCare and Delsam Pharma artificial tears and ointment products were recalled after being linked to the bacterium P. aeruginosa. The bacteria have caused at least 68 infections, including three deaths and at least eight cases of blindness. The eyedrops were imported to the United States from India, and many of the cases occurred after the bacteria spread person-to-person at a long-term care facility in Connecticut, according to the Times, which cited FDA and Centers for Disease Control and Prevention lead investigator Maroya Walters, PhD.

Dr. Walters said the cases that caused death or blindness were traced to the EzriCare artificial tears product.

“It’s very hard to get rid of,” University of North Carolina at Chapel Hill infectious disease specialist David van Duin, MD, PhD, told the Times, noting that the bacteria cling to sink drains, water faucets, and other moist places. 

The FDA said it had halted the import of the recalled products and has since visited the plant in India where they were made, which is owned by Global Pharma Healthcare. In a citation to the company dated March 2, the FDA listed nearly a dozen problems, such as dirty equipment and the absence of safety procedures and tests. 

A version of this article originally appeared on WebMD.com.

Contaminated, deadly, and blindness-causing eyedrops that were recalled earlier this year were made in India at a factory not inspected by the U.S. Food and Drug Administration, according to a new report. 

Scientists are concerned that the once-rare treatment-resistant bacteria found in the eyedrops can spread person-to-person, posing a risk of becoming a recurrent problem in the United States, The New York Times reported.

In January, EzriCare and Delsam Pharma artificial tears and ointment products were recalled after being linked to the bacterium P. aeruginosa. The bacteria have caused at least 68 infections, including three deaths and at least eight cases of blindness. The eyedrops were imported to the United States from India, and many of the cases occurred after the bacteria spread person-to-person at a long-term care facility in Connecticut, according to the Times, which cited FDA and Centers for Disease Control and Prevention lead investigator Maroya Walters, PhD.

Dr. Walters said the cases that caused death or blindness were traced to the EzriCare artificial tears product.

“It’s very hard to get rid of,” University of North Carolina at Chapel Hill infectious disease specialist David van Duin, MD, PhD, told the Times, noting that the bacteria cling to sink drains, water faucets, and other moist places. 

The FDA said it had halted the import of the recalled products and has since visited the plant in India where they were made, which is owned by Global Pharma Healthcare. In a citation to the company dated March 2, the FDA listed nearly a dozen problems, such as dirty equipment and the absence of safety procedures and tests. 

A version of this article originally appeared on WebMD.com.

Contaminated, deadly, and blindness-causing eyedrops that were recalled earlier this year were made in India at a factory not inspected by the U.S. Food and Drug Administration, according to a new report. 

Scientists are concerned that the once-rare treatment-resistant bacteria found in the eyedrops can spread person-to-person, posing a risk of becoming a recurrent problem in the United States, The New York Times reported.

In January, EzriCare and Delsam Pharma artificial tears and ointment products were recalled after being linked to the bacterium P. aeruginosa. The bacteria have caused at least 68 infections, including three deaths and at least eight cases of blindness. The eyedrops were imported to the United States from India, and many of the cases occurred after the bacteria spread person-to-person at a long-term care facility in Connecticut, according to the Times, which cited FDA and Centers for Disease Control and Prevention lead investigator Maroya Walters, PhD.

Dr. Walters said the cases that caused death or blindness were traced to the EzriCare artificial tears product.

“It’s very hard to get rid of,” University of North Carolina at Chapel Hill infectious disease specialist David van Duin, MD, PhD, told the Times, noting that the bacteria cling to sink drains, water faucets, and other moist places. 

The FDA said it had halted the import of the recalled products and has since visited the plant in India where they were made, which is owned by Global Pharma Healthcare. In a citation to the company dated March 2, the FDA listed nearly a dozen problems, such as dirty equipment and the absence of safety procedures and tests. 

A version of this article originally appeared on WebMD.com.

The 2022 mpox (monkeypox) virus outbreak represents the latest example of how infectious diseases with previously limited reach can spread in a globalized society. More than 86,000 cases have been reported worldwide, with more than 30,000 cases in the United States as of March 15, 2023.¹ Herein, we summarize the key features of mpox infection for the dermatologist.

Mpox Transmission

The mpox virus is a double-stranded DNA virus of the Orthopoxvirus genus and Poxviridae family.^2,3 There are 2 types of the mpox virus: clade I (formerly the Congo Basin clade) and clade II (formerly the West African clade). Clade I causes more severe disease (10% mortality rate), while clade II is associated with lower mortality (1%–3%) and has been split into subclades of IIa (exhibits zoonotic transmission) and IIb (exhibits human-to-human spread).^3,4 The current outbreak is caused by clade IIb, and patients typically have no travel history to classic endemic regions.^5,6

In endemic countries, mpox transmission is zoonotic from small forest animals. In nonendemic countries, sporadic cases rarely have been reported, including a cluster in the United States in 2003 related to pet prairie dogs. In stark contrast, human-to-human transmission is occurring in the current epidemic mainly via intimate skin-to-skin contact and possibly via sexual fluids, meeting the criteria for a sexually transmitted infection. However, nonsexual transmission does still occur, though it is less common.⁷ Many of the reported cases so far are in young to middle-aged men who have sex with men (MSM).^2,8 However, it is crucial to understand that mpox is not exclusive to the MSM population; the virus has been transmitted to heterosexual males, females, children, and even household pets of infected individuals.^2,9,10 Labeling mpox as exclusive to the MSM community is both inaccurate and inappropriately stigmatizing.

Cutaneous Presentation and Diagnosis of Mpox

Mpox has an incubation time of approximately 9 days (range, 7–21 days), after which affected persons develop macular lesions that evolve over 2 to 4 weeks into papules, vesicles, and deep-seated pustules before crusting over and resolving with possible residual scarring.^{2,3,5,9,11,12} Palmoplantar involvement is a key feature.¹¹ Although in some cases there will be multiple lesions with centrifugal progression, the lesions also may be few in number, with some patients presenting with a single lesion in the anogenital region or on the face, hand, or foot (Figure).^6,9 Systemic symptoms such as prodromal fever, lymphadenopathy, and headache are common but not universal.^9,13 Potential complications include penile edema, proctitis, bacterial superinfection, tonsillitis, conjunctivitis, encephalitis, and pneumonia.^5,9,13

Images used with permission from Roneet Lev, MD (San Diego, California), and VisualDx.

A high index of suspicion is needed to diagnose mpox infection. The differential diagnosis includes smallpox; varicella-zoster virus (primary or reactivation); secondary syphilis; measles; herpes simplex virus; molluscum contagiosum; hand, foot, and mouth disease; and disseminated gonococcal infection.^2,3 For lesions confined to the genital area, sexually transmitted infections (eg, chancroid, lymphogranuloma venereum) as well as non–sexually related acute genital ulcers (Lipschütz ulcers) should be considered.²

Certain clinical features may help in distinguishing mpox from other diseases. Mpox exhibits synchronous progression and centrifugal distribution when multiple lesions are present; in contrast, the lesions of primary varicella (chickenpox) appear in multiple different stages, and those of localized herpes zoster (shingles) exhibit a dermatomal distribution. When these features are present, mpox causes a greater degree of lymphadenopathy and systemic symptoms than primary varicella.³Clinical diagnosis of mpox is more than 90% sensitive but only 9% to 26% specific.³ To confirm the diagnosis, a viral swab vigorously obtained from active skin lesions should be sent in viral transport media for mpox DNA-specific polymerase chain reaction testing, which is available from major laboratories.^2,3 Other supportive tests include serum studies for anti–mpox virus immunoglobulins and immunohistochemical staining for viral antigens on skin biopsy specimens.² When evaluating suspected and confirmed mpox cases, dermatologists should wear a gown, gloves, a fitted N95 mask, and eye protection to prevent infection.⁵

Treating Mpox

Symptomatic mpox infection can last for up to 2 to 5 weeks.³ The patient is no longer infectious once the lesions have crusted over.^3,11 The majority of cases require supportive care only.^2,3,5,14 However, mpox remains a potentially fatal disease, with 38 deaths to date in the current outbreak.¹ High-risk populations include children younger than 8 years, pregnant women, and individuals who are immunocompromised.¹⁵ Tecovirimat, an antiviral medication approved by the US Food and Drug Administration (FDA) for smallpox, is available via the expanded access Investigational New Drug (EA-IND) protocol to treat severe mpox cases but is not widely available in the United States.^6,16-18 Brincidofovir, a prodrug of the antiviral cidofovir, possesses single-patient emergency use Investigational New Drug (e-IND) status for treatment of mpox but also is not widely available in the United States.¹⁷ Intravenous vaccinia immune globulin is under consideration for high-risk individuals, but little is known regarding its efficacy against mpox.^5,16,17

Two smallpox vaccines—JYNNEOS (Bavarian Nordic) and ACAM2000 (Emergent Bio Solutions)—are available for both preexposure and postexposure prophylaxis against mpox virus.¹⁹ At this time, only JYNNEOS is FDA approved for the prevention of mpox; ACAM2000 can be used against mpox under the FDA’s EA-IND protocol, which involves additional requirements, including informed consent from the patient.²⁰ ACAM2000 is a live, replication-competent vaccine that carries a warning of increased risk for side effects in patients with cardiac disease, pregnancy, immunocompromise, and a history or presence of eczema and other skin conditions.^3,21,22 JYNNEOS is a live but replication-deficient virus and therefore does not carry these warnings.^3,21,22

Final Thoughts

Mpox is no longer an obscure illness occurring in limited geographic areas. Dermatologists must remain highly vigilant when evaluating any patient for new-onset vesicular or pustular eruptions to combat this ongoing public health threat. This issue of Cutis^® also features a thorough mpox update on the clinical presentation, vaccine guidance, and management.²³

The 2022 mpox (monkeypox) virus outbreak represents the latest example of how infectious diseases with previously limited reach can spread in a globalized society. More than 86,000 cases have been reported worldwide, with more than 30,000 cases in the United States as of March 15, 2023.¹ Herein, we summarize the key features of mpox infection for the dermatologist.

Mpox Transmission

The mpox virus is a double-stranded DNA virus of the Orthopoxvirus genus and Poxviridae family.^2,3 There are 2 types of the mpox virus: clade I (formerly the Congo Basin clade) and clade II (formerly the West African clade). Clade I causes more severe disease (10% mortality rate), while clade II is associated with lower mortality (1%–3%) and has been split into subclades of IIa (exhibits zoonotic transmission) and IIb (exhibits human-to-human spread).^3,4 The current outbreak is caused by clade IIb, and patients typically have no travel history to classic endemic regions.^5,6

In endemic countries, mpox transmission is zoonotic from small forest animals. In nonendemic countries, sporadic cases rarely have been reported, including a cluster in the United States in 2003 related to pet prairie dogs. In stark contrast, human-to-human transmission is occurring in the current epidemic mainly via intimate skin-to-skin contact and possibly via sexual fluids, meeting the criteria for a sexually transmitted infection. However, nonsexual transmission does still occur, though it is less common.⁷ Many of the reported cases so far are in young to middle-aged men who have sex with men (MSM).^2,8 However, it is crucial to understand that mpox is not exclusive to the MSM population; the virus has been transmitted to heterosexual males, females, children, and even household pets of infected individuals.^2,9,10 Labeling mpox as exclusive to the MSM community is both inaccurate and inappropriately stigmatizing.

Cutaneous Presentation and Diagnosis of Mpox

Mpox has an incubation time of approximately 9 days (range, 7–21 days), after which affected persons develop macular lesions that evolve over 2 to 4 weeks into papules, vesicles, and deep-seated pustules before crusting over and resolving with possible residual scarring.^{2,3,5,9,11,12} Palmoplantar involvement is a key feature.¹¹ Although in some cases there will be multiple lesions with centrifugal progression, the lesions also may be few in number, with some patients presenting with a single lesion in the anogenital region or on the face, hand, or foot (Figure).^6,9 Systemic symptoms such as prodromal fever, lymphadenopathy, and headache are common but not universal.^9,13 Potential complications include penile edema, proctitis, bacterial superinfection, tonsillitis, conjunctivitis, encephalitis, and pneumonia.^5,9,13

Images used with permission from Roneet Lev, MD (San Diego, California), and VisualDx.

A high index of suspicion is needed to diagnose mpox infection. The differential diagnosis includes smallpox; varicella-zoster virus (primary or reactivation); secondary syphilis; measles; herpes simplex virus; molluscum contagiosum; hand, foot, and mouth disease; and disseminated gonococcal infection.^2,3 For lesions confined to the genital area, sexually transmitted infections (eg, chancroid, lymphogranuloma venereum) as well as non–sexually related acute genital ulcers (Lipschütz ulcers) should be considered.²

Certain clinical features may help in distinguishing mpox from other diseases. Mpox exhibits synchronous progression and centrifugal distribution when multiple lesions are present; in contrast, the lesions of primary varicella (chickenpox) appear in multiple different stages, and those of localized herpes zoster (shingles) exhibit a dermatomal distribution. When these features are present, mpox causes a greater degree of lymphadenopathy and systemic symptoms than primary varicella.³Clinical diagnosis of mpox is more than 90% sensitive but only 9% to 26% specific.³ To confirm the diagnosis, a viral swab vigorously obtained from active skin lesions should be sent in viral transport media for mpox DNA-specific polymerase chain reaction testing, which is available from major laboratories.^2,3 Other supportive tests include serum studies for anti–mpox virus immunoglobulins and immunohistochemical staining for viral antigens on skin biopsy specimens.² When evaluating suspected and confirmed mpox cases, dermatologists should wear a gown, gloves, a fitted N95 mask, and eye protection to prevent infection.⁵

Treating Mpox

Symptomatic mpox infection can last for up to 2 to 5 weeks.³ The patient is no longer infectious once the lesions have crusted over.^3,11 The majority of cases require supportive care only.^2,3,5,14 However, mpox remains a potentially fatal disease, with 38 deaths to date in the current outbreak.¹ High-risk populations include children younger than 8 years, pregnant women, and individuals who are immunocompromised.¹⁵ Tecovirimat, an antiviral medication approved by the US Food and Drug Administration (FDA) for smallpox, is available via the expanded access Investigational New Drug (EA-IND) protocol to treat severe mpox cases but is not widely available in the United States.^6,16-18 Brincidofovir, a prodrug of the antiviral cidofovir, possesses single-patient emergency use Investigational New Drug (e-IND) status for treatment of mpox but also is not widely available in the United States.¹⁷ Intravenous vaccinia immune globulin is under consideration for high-risk individuals, but little is known regarding its efficacy against mpox.^5,16,17

Two smallpox vaccines—JYNNEOS (Bavarian Nordic) and ACAM2000 (Emergent Bio Solutions)—are available for both preexposure and postexposure prophylaxis against mpox virus.¹⁹ At this time, only JYNNEOS is FDA approved for the prevention of mpox; ACAM2000 can be used against mpox under the FDA’s EA-IND protocol, which involves additional requirements, including informed consent from the patient.²⁰ ACAM2000 is a live, replication-competent vaccine that carries a warning of increased risk for side effects in patients with cardiac disease, pregnancy, immunocompromise, and a history or presence of eczema and other skin conditions.^3,21,22 JYNNEOS is a live but replication-deficient virus and therefore does not carry these warnings.^3,21,22

Final Thoughts

Mpox is no longer an obscure illness occurring in limited geographic areas. Dermatologists must remain highly vigilant when evaluating any patient for new-onset vesicular or pustular eruptions to combat this ongoing public health threat. This issue of Cutis^® also features a thorough mpox update on the clinical presentation, vaccine guidance, and management.²³

The 2022 mpox (monkeypox) virus outbreak represents the latest example of how infectious diseases with previously limited reach can spread in a globalized society. More than 86,000 cases have been reported worldwide, with more than 30,000 cases in the United States as of March 15, 2023.¹ Herein, we summarize the key features of mpox infection for the dermatologist.

Mpox Transmission

The mpox virus is a double-stranded DNA virus of the Orthopoxvirus genus and Poxviridae family.^2,3 There are 2 types of the mpox virus: clade I (formerly the Congo Basin clade) and clade II (formerly the West African clade). Clade I causes more severe disease (10% mortality rate), while clade II is associated with lower mortality (1%–3%) and has been split into subclades of IIa (exhibits zoonotic transmission) and IIb (exhibits human-to-human spread).^3,4 The current outbreak is caused by clade IIb, and patients typically have no travel history to classic endemic regions.^5,6

In endemic countries, mpox transmission is zoonotic from small forest animals. In nonendemic countries, sporadic cases rarely have been reported, including a cluster in the United States in 2003 related to pet prairie dogs. In stark contrast, human-to-human transmission is occurring in the current epidemic mainly via intimate skin-to-skin contact and possibly via sexual fluids, meeting the criteria for a sexually transmitted infection. However, nonsexual transmission does still occur, though it is less common.⁷ Many of the reported cases so far are in young to middle-aged men who have sex with men (MSM).^2,8 However, it is crucial to understand that mpox is not exclusive to the MSM population; the virus has been transmitted to heterosexual males, females, children, and even household pets of infected individuals.^2,9,10 Labeling mpox as exclusive to the MSM community is both inaccurate and inappropriately stigmatizing.

Cutaneous Presentation and Diagnosis of Mpox

Mpox has an incubation time of approximately 9 days (range, 7–21 days), after which affected persons develop macular lesions that evolve over 2 to 4 weeks into papules, vesicles, and deep-seated pustules before crusting over and resolving with possible residual scarring.^{2,3,5,9,11,12} Palmoplantar involvement is a key feature.¹¹ Although in some cases there will be multiple lesions with centrifugal progression, the lesions also may be few in number, with some patients presenting with a single lesion in the anogenital region or on the face, hand, or foot (Figure).^6,9 Systemic symptoms such as prodromal fever, lymphadenopathy, and headache are common but not universal.^9,13 Potential complications include penile edema, proctitis, bacterial superinfection, tonsillitis, conjunctivitis, encephalitis, and pneumonia.^5,9,13

Images used with permission from Roneet Lev, MD (San Diego, California), and VisualDx.

A high index of suspicion is needed to diagnose mpox infection. The differential diagnosis includes smallpox; varicella-zoster virus (primary or reactivation); secondary syphilis; measles; herpes simplex virus; molluscum contagiosum; hand, foot, and mouth disease; and disseminated gonococcal infection.^2,3 For lesions confined to the genital area, sexually transmitted infections (eg, chancroid, lymphogranuloma venereum) as well as non–sexually related acute genital ulcers (Lipschütz ulcers) should be considered.²

Certain clinical features may help in distinguishing mpox from other diseases. Mpox exhibits synchronous progression and centrifugal distribution when multiple lesions are present; in contrast, the lesions of primary varicella (chickenpox) appear in multiple different stages, and those of localized herpes zoster (shingles) exhibit a dermatomal distribution. When these features are present, mpox causes a greater degree of lymphadenopathy and systemic symptoms than primary varicella.³Clinical diagnosis of mpox is more than 90% sensitive but only 9% to 26% specific.³ To confirm the diagnosis, a viral swab vigorously obtained from active skin lesions should be sent in viral transport media for mpox DNA-specific polymerase chain reaction testing, which is available from major laboratories.^2,3 Other supportive tests include serum studies for anti–mpox virus immunoglobulins and immunohistochemical staining for viral antigens on skin biopsy specimens.² When evaluating suspected and confirmed mpox cases, dermatologists should wear a gown, gloves, a fitted N95 mask, and eye protection to prevent infection.⁵

Treating Mpox

Symptomatic mpox infection can last for up to 2 to 5 weeks.³ The patient is no longer infectious once the lesions have crusted over.^3,11 The majority of cases require supportive care only.^2,3,5,14 However, mpox remains a potentially fatal disease, with 38 deaths to date in the current outbreak.¹ High-risk populations include children younger than 8 years, pregnant women, and individuals who are immunocompromised.¹⁵ Tecovirimat, an antiviral medication approved by the US Food and Drug Administration (FDA) for smallpox, is available via the expanded access Investigational New Drug (EA-IND) protocol to treat severe mpox cases but is not widely available in the United States.^6,16-18 Brincidofovir, a prodrug of the antiviral cidofovir, possesses single-patient emergency use Investigational New Drug (e-IND) status for treatment of mpox but also is not widely available in the United States.¹⁷ Intravenous vaccinia immune globulin is under consideration for high-risk individuals, but little is known regarding its efficacy against mpox.^5,16,17

Two smallpox vaccines—JYNNEOS (Bavarian Nordic) and ACAM2000 (Emergent Bio Solutions)—are available for both preexposure and postexposure prophylaxis against mpox virus.¹⁹ At this time, only JYNNEOS is FDA approved for the prevention of mpox; ACAM2000 can be used against mpox under the FDA’s EA-IND protocol, which involves additional requirements, including informed consent from the patient.²⁰ ACAM2000 is a live, replication-competent vaccine that carries a warning of increased risk for side effects in patients with cardiac disease, pregnancy, immunocompromise, and a history or presence of eczema and other skin conditions.^3,21,22 JYNNEOS is a live but replication-deficient virus and therefore does not carry these warnings.^3,21,22

Final Thoughts

Mpox is no longer an obscure illness occurring in limited geographic areas. Dermatologists must remain highly vigilant when evaluating any patient for new-onset vesicular or pustular eruptions to combat this ongoing public health threat. This issue of Cutis^® also features a thorough mpox update on the clinical presentation, vaccine guidance, and management.²³

The mpox (monkeypox) virus is a zoonotic orthopox DNA virus that results in a smallpoxlike illness.¹ Vaccination against smallpox protects against other orthopox infections, including mpox; however, unlike smallpox, mpox is notable for a variety of not-yet-confirmed animal reservoirs.² Mpox was first identified in Denmark in 1959 among nonhuman primates imported from Singapore, and the first case of human infection was diagnosed in 1970 in a 9-month-old child in the Democratic Republic of Congo.³ Endemic regions of Africa have had sporadic outbreaks with increasing frequency over time since the cessation of smallpox vaccination in 1980.^2,4 Infections in nonendemic countries have occurred intermittently, including in 2003 in the Midwest United States. This outbreak was traced back to prairie dogs infected by exotic animals imported from the Republic of Ghana.⁵

Two genetic clades of mpox that differ in mortality rates have been identified: clade II (formerly the West African clade) generally is self-limited with an estimated mortality of 1% to 6%, whereas clade I (formerly the Congo Basin clade) is more transmissible, with a mortality of approximately 10%.^2,6,7 Notably, as of May 2, 2022, all polymerase chain reaction–confirmed cases of mpox in nonendemic countries were identified as clade II.⁷ Following the continued international spread of mpox, the Director-General of the World Health Organization (WHO) declared the global outbreak a public health emergency of international concern on July 23, 2022.⁸ As of March 1, 2023, the Centers for Disease Control and Prevention (CDC) reports that there have been more than 86,000 cases of laboratory-confirmed mpox worldwide and 105 deaths, 89 of which occurred in nonendemic regions.⁹

Transmission of Mpox

In endemic countries, cases have been largely reported secondary to zoonotic spillover from contact with an infected animal.⁶ However, in nonendemic countries, mpox often results from human-to-human transmission, primarily via skin-to-skin contact with infected skin, but also may occur indirectly via contaminated fomites such as bedding or clothing, respiratory secretions, or vertical transmission.^6,10 The indirect transmission of mpox via contaminated fomites is controversial, though some studies have shown the virus can survive on surfaces for up to 15 days.¹¹ In the current outbreak, human-to-human transmission has been strongly associated with close contact during sexual activity, particularly among men who have sex with men (MSM), with notable physical concentration of initial lesions in the genital region.¹² Anyone can acquire mpox—infections are not exclusive to MSM populations, and cases have been reported in all demographic groups, including women and children. It is important to avoid stigmatization of MSM to prevent the propagation of homophobia as well as a false sense of complacency in non-MSM populations.¹³

Clinical Presentation of Mpox

The incubation period of mpox has been reported to last up to 21 days and is posited to depend on the mode of transmission, with complex invasive exposures having a shorter duration of approximately 9 days compared to noninvasive exposures, which have a duration of approximately 13 days.¹⁴ In a recent report from the Netherlands, the average incubation time was 8.5 days in 18 men with exposure attributed to sexual encounters with men.¹² Following the incubation period, mpox infection typically presents with nonspecific systemic symptoms such as fever, malaise, sore throat, cough, and headache for approximately 2 days, followed by painful generalized or localized lymphadenopathy 1 to 2 days prior to the onset of skin lesions.^1,15 In a recent report from Portugal of more than 20 confirmed cases of mpox, approximately half of patients denied symptoms or had mild systemic symptoms, suggesting that many patients in the current outbreak do not endorse systemic symptoms.¹⁶

Classic cutaneous lesions are the hallmark feature of mpox.¹⁷ Over a period of 1 to 2 weeks, each lesion progresses through morphologic stages of macule, papule (Figure), vesicle, and pustule, which then crusts over, forming a scab that falls off after another 1 to 2 weeks and can result in dyspigmented or pitted scars.^1,15 Lesions may be deep-seated or umbilicated; previously they were noted to typically start on the face and spread centrifugally, but recent cases have been notable for a predominance of anogenital lesions, often with the anogenital area as the sole or primary area of involvement.¹⁸ Given the high proportion of anogenital lesions in 2022, symptoms such as anogenital pain, tenesmus, and diarrhea are not uncommon.¹⁹ A recent study describing 528 international cases of mpox revealed that 95% of patients presented with a rash; nearly 75% had anogenital lesions; and 41%, 25%, and 10% had involvement of mucosae, the face, and palms/soles, respectively. More than half of patients had fewer than 10 lesions, and 10% presented with a single genital lesion.¹⁹

Given the recent predilection of lesions for the anogenital area, the differential diagnosis of mpox should include other common infections localized to these areas. Unlike herpes simplex and varicella-zoster infections, mpox does not exhibit the classic herpetiform clustering of vesicles, and unlike the painless chancre of syphilis, the lesions of mpox are exquisitely painful. Similar to chancroid, mpox presents with painful genital lesions and lymphadenopathy, and the umbilicated papules of molluscum could easily be confused with mpox lesions. Proctitis caused by many sexually transmitted infections (STIs), including chlamydia and gonorrhea, may be difficult to differentiate from proctitis symptoms of mpox. Co-infection with HIV and other STIs is common among patients developing mpox in 2022, which is not surprising given that the primary mechanism of transmission of mpox at this time is through sexual contact, and cases are more common in patients with multiple recent sexual partners.¹⁹ Considering these shared risk factors and similar presentation of multiple STIs, patients suspected of having an mpox infection should be tested for other STIs, including HIV.

Complications of Mpox

Although mpox generally is characterized by a mild disease course, there is concern for adverse outcomes, particularly in more vulnerable populations, including immunocompromised, pregnant, and pediatric populations. Complications of infection can include sepsis, encephalitis, bronchopneumonia, and ophthalmic complications that can result in loss of vision.^6,17 The most common complications requiring hospitalization in a recent international report of 528 mpox cases were pain management, which was primarily due to severe anogenital pain, followed by soft-tissue superinfection, with other complications including severe pharyngitis limiting oral intake and infection control practices.¹⁹ In addition to severe rectal pain, proctitis and even rectal perforation have been reported.^19,20

Vertical transmission has been described with devastating outcomes in a case series from the Democratic Republic of Congo, where 4 cases of mpox were identified in pregnant women; 3 of these pregnancies resulted in fetal demise.¹⁰ The only fetus to survive was born to a mother with mild infection. In comparison, 2 of 3 mothers with moderate to severe disease experienced spontaneous abortion in the first trimester, and 1 pregnancy ended due to intrauterine demise during the eighteenth week of gestation, likely a complication of mpox. These cases suggest that more severe disease may be linked to worse fetal outcomes.¹⁰ Further epidemiologic studies will be crucial, given the potential implications.

Diagnosis

When considering a diagnosis of mpox, clinicians should inquire about recent travel, living arrangements, sexual history, and recent sick contacts.⁶ A complete skin examination should include the oral and genital areas, given the high prevalence of lesions in these areas. A skin biopsy is not recommended for the diagnosis of mpox, as nonspecific viral changes cannot be differentiated from other viral exanthems, but it often is useful to rule out other differential diagnoses.²¹ Additionally, immunohistochemistry and electron microscopy can be utilized to aid in a histologic diagnosis of mpox.

Polymerase chain reaction detection of orthopox or mpox DNA is the gold standard for diagnosis.⁶ Two swabs should be collected from each lesion by swabbing vigorously using sterile swabs made of a synthetic material such as polyester, nylon, or Dacron and placed into a sterile container or viral transport medium.²² Some laboratories may have different instructions for collection of samples, so clinicians are advised to check for instructions from their local laboratory. Deroofing lesions prior to swabbing is not necessary, and specimens can include lesional material or crust. Collection of specimens from 2 to 3 lesions is recommended, preferably from different body areas or lesions with varying morphologies. Anal or rectal swabs can be considered in patients presenting with anal pain or proctitis with clinical suspicion for mpox based on history.¹⁹

Infection Prevention

Interim guidance from the WHO on November 16, 2022, reiterated the goal of outbreak control primarily via public health measures, which includes targeted use of vaccines for at-risk populations or postexposure prophylactic vaccination within 4 days, but heavily relies on surveillance and containment techniques, such as contact tracing with monitoring of contacts for onset of symptoms and isolation of cases through the complete infectious period.²³ Patients are considered infectious from symptom onset until all cutaneous lesions are re-epithelized and should remain in isolation, including from household contacts and domestic and wildlife animals, for the duration of illness.^24,25 Individuals exposed to humans or animals with confirmed mpox should be monitored for the development of symptoms for 21 days following last known exposure, regardless of vaccination status, and should be instructed to measure their temperature twice daily.²⁶ Pets exposed to mpox should be isolated from other animals and humans for 21 days following last known contact.²⁴ Vaccination strategies for preexposure and postexposure prophylaxis (PEP) are discussed below in further detail. Postinfection, the WHO suggests use of condoms for all oral, vaginal, and anal sexual activity for 12 weeks after recovery.⁷

Patients with suspected or confirmed mpox in a hospital should be in a single private room on special droplet and contact precautions.²⁷ No special air handling or negative pressure isolation is needed unless the patient is undergoing an aerosol-generating procedure (eg, intubation, endoscopy, bronchoscopy). When hospitalized, patients should have a dedicated bathroom, if possible, and at-home patients should be isolated from household members until contagion risk resolves; this includes the use of a separate bathroom, when possible. Health care personnel entering the room of a patient should don appropriate personal protective equipment (PPE), including a disposable gown, gloves, eye protection, and N95 respirator or equivalent. Recommendations include standard practices for cleaning, with wet cleaning methods preferred over dry methods, using a disinfectant that covers emerging viral pathogens, and avoidance of shaking linens to prevent the spread of infectious particles.²⁷ A variety of Environmental Protection Agency–registered wipes with virucidal activity against emerging viruses, including those with active ingredients such as quaternary ammonium, hydrogen peroxide, and hypochlorous acid, should be used for disinfecting surfaces.²⁸

Vaccination

ACAM2000 (Emergent Bio Solutions) and JYNNEOS (Bavarian Nordic)(also known as Imvamune or Imvanex) are available in the United States for the prevention of mpox infection.²⁹ ACAM2000, a second-generation, replication-competent, live smallpox vaccine administered as a single percutaneous injection, is contraindicated in immunocompromised populations, including patients with HIV or on immunosuppressive or biologic therapy, pregnant individuals, people with a history of atopic dermatitis or other exfoliative skin diseases with impaired barrier function, and patients with a history of cardiac disease due to the risk of myocarditis and pericarditis.³⁰

JYNNEOS is a nonreplicating live vaccine approved by the US Food and Drug Administration (FDA) for the prevention of mpox in individuals older than 18 years administered as 2 subcutaneous doses 4 weeks apart. Patients are considered fully vaccinated 2 weeks after the second dose, and JYNNEOS is available to pediatric patients with a single patient expanded access use authorization from the FDA.^29,30 More recently, the FDA issued an emergency use authorization (EUA) for administration of the vaccine to patients younger than 18 years who are at high risk of infection after exposure.³¹ More importantly, the FDA also issued an EUA for the intradermal administration of JYNNEOS at one-fifth of the subcutaneous dose to expand the current vaccine supply. This EUA is based on research by Frey et al,³² which showed that intradermal administration, even at a lower dose, elicited similar immune responses among study participants as the higher dose administered subcutaneously.

JYNNEOS is the preferred vaccine for the prevention of mpox because of its poor ability to replicate in human cells and resultant safety for use in populations that are immunocompromised, pregnant, or have skin barrier defects such as atopic dermatitis, without the risk of myocarditis or pericarditis. However, current supplies are limited. JYNNEOS was specifically studied in patients with atopic dermatitis and has been shown to be safe and effective in patients with a history of atopic dermatitis and active disease with a SCORAD (SCORing Atopic Dermatitis) score of 30 or lower.³³ Of note, JYNNEOS is contraindicated in patients allergic to components of the vaccine, including egg, gentamicin, and ciprofloxacin. Although JYNNEOS is safe to administer to persons with immunocompromising conditions, the CDC reports that such persons might be at increased risk for severe disease if an occupational infection occurs, and in the setting of immunocompromise, such persons may be less likely to mount an effective response to vaccination. Therefore, the risk-benefit ratio should be considered to determine if an immunocompromised person should be vaccinated with JYNNEOS.³⁰

The WHO and the CDC do not recommended mass vaccination of the general public for outbreaks of mpox in nonendemic countries, with immunization reserved for appropriate PEP and pre-exposure prophylaxis in intermediate- to high-risk individuals.^23,26 The CDC recommends PEP vaccination for individuals with a high degree of exposure that includes unprotected contact of the skin or mucous membranes of an individual to the skin, lesions, body fluids, or contaminated fomites from a patient with mpox, as well as being within 6 feet of a patient during an aerosolization procedure without proper PPE. Following an intermediate degree of exposure, which includes being within 6 feet for 3 or more hours wearing at minimum a surgical mask or contact with fomites while wearing incomplete PPE, the CDC recommends monitoring and shared decision-making regarding risks and benefits of PEP vaccination. Monitoring without PEP is indicated for low and uncertain degrees of exposure, including entering a room without full PPE such as eye protection, regardless of the duration of contact.^23,26

Postexposure prophylaxis vaccination should be administered within 4 days of a known high-level exposure to mpox to prevent infection.²⁹ If administered within 4 to 14 days postexposure, vaccination may reduce disease severity but will not prevent infection.³⁴

Pre-exposure prophylaxis is recommended for individuals at high risk for exposure to mpox, including health care workers such as laboratory personnel who handle mpox specimens and health care workers who administer ACAM2000 vaccinations or anticipate providing care for many patients with mpox.³⁴

Management

Most cases of mpox are characterized by mild to moderate disease with a self-limited course. Most commonly, medical management of mpox involves supportive care such as fluid resuscitation, supplemental oxygen, and pain management.⁶ Treatment of superinfected skin lesions may require antibiotics. In the event of ophthalmologic involvement, patients should be referred to an ophthalmologist for further management.

Currently, there are no FDA-approved therapies for mpox; however, tecovirimat, cidofovir, brincidofovir, and vaccinia immune globulin intravenous are available under expanded access Investigational New Drug protocols.^6,35 Human data for cidofovir, brincidofovir, and vaccinia immune globulin intravenous in the treatment of mpox are lacking, while cidofovir and brincidofovir have shown efficacy against orthopoxviruses in in vitro and animal studies, but are available therapeutic options.³⁵

Tecovirimat is an antiviral that is FDA approved for smallpox with efficacy data against mpox in animal studies. It is the first-line treatment for patients with severe disease requiring hospitalization or 1 or more complications, including dehydration or secondary skin infections, as well as for populations at risk for severe disease, which includes immunocompromised patients, pediatric patients younger than 8 years, pregnant or breastfeeding individuals, or patients with a history of atopic dermatitis or active exfoliative skin conditions.³⁶ In this current outbreak, both intravenous and oral tecovirimat are weight based in adult and pediatric patients for 14 days, with the intravenous form dosed every 12 hours by infusion over 6 hours, and the oral doses administered every 8 to 12 hours based on patient weight.³⁷ Tecovirimat generally is well tolerated with mild side effects but is notably contraindicated in patients with severe renal impairment with a creatinine clearance less than 30 mL/min, and renal monitoring is indicated in pediatric patients younger than 2 years and in all patients receiving intravenous treatment.

Conclusion

Given that cutaneous lesions are the most specific presenting sign of mpox infection, dermatologists will play an integral role in identifying future cases and managing future outbreaks. Mpox should be considered in the differential diagnosis for all patients presenting with umbilicated or papulovesicular lesions, particularly in an anogenital distribution. The classic presentation of mpox may be more common among patients who are not considered high risk and have not been exposed via sexual activity. All patients with suspicious lesions should be managed following appropriate infection control precautions and should undergo molecular diagnostic assay of swabbed lesions to confirm the diagnosis. JYNNEOS is the only vaccine that is currently being distributed in the United States and is safe to administer to immunocompromised populations. The risks and benefits of vaccination should be considered on an individual basis between a patient and their provider. Taking into consideration that patients with atopic dermatitis are at risk for severe disease if infected with mpox, vaccination should be strongly encouraged if indicated based on patient risk factors. For atopic dermatitis patients treated with dupilumab, shared decision-making is essential given the FDA label, which recommends avoiding the use of live vaccines.³⁸

The mpox epidemic occurring amidst the ongoing COVID-19 pandemic should serve as a wake-up call to the importance of pandemic preparedness and the global health response strategies in the modern era of globalization. Looking forward, widespread vaccination against mpox may be necessary to control the spread of the disease and to protect vulnerable populations, including pregnant individuals. In the current climate of hesitancy surrounding vaccines and the erosion of trust in public health agencies, it is incumbent upon health care providers to educate patients regarding the role of vaccines and public health measures to control this developing global health crisis.

The mpox (monkeypox) virus is a zoonotic orthopox DNA virus that results in a smallpoxlike illness.¹ Vaccination against smallpox protects against other orthopox infections, including mpox; however, unlike smallpox, mpox is notable for a variety of not-yet-confirmed animal reservoirs.² Mpox was first identified in Denmark in 1959 among nonhuman primates imported from Singapore, and the first case of human infection was diagnosed in 1970 in a 9-month-old child in the Democratic Republic of Congo.³ Endemic regions of Africa have had sporadic outbreaks with increasing frequency over time since the cessation of smallpox vaccination in 1980.^2,4 Infections in nonendemic countries have occurred intermittently, including in 2003 in the Midwest United States. This outbreak was traced back to prairie dogs infected by exotic animals imported from the Republic of Ghana.⁵

Two genetic clades of mpox that differ in mortality rates have been identified: clade II (formerly the West African clade) generally is self-limited with an estimated mortality of 1% to 6%, whereas clade I (formerly the Congo Basin clade) is more transmissible, with a mortality of approximately 10%.^2,6,7 Notably, as of May 2, 2022, all polymerase chain reaction–confirmed cases of mpox in nonendemic countries were identified as clade II.⁷ Following the continued international spread of mpox, the Director-General of the World Health Organization (WHO) declared the global outbreak a public health emergency of international concern on July 23, 2022.⁸ As of March 1, 2023, the Centers for Disease Control and Prevention (CDC) reports that there have been more than 86,000 cases of laboratory-confirmed mpox worldwide and 105 deaths, 89 of which occurred in nonendemic regions.⁹

Transmission of Mpox

In endemic countries, cases have been largely reported secondary to zoonotic spillover from contact with an infected animal.⁶ However, in nonendemic countries, mpox often results from human-to-human transmission, primarily via skin-to-skin contact with infected skin, but also may occur indirectly via contaminated fomites such as bedding or clothing, respiratory secretions, or vertical transmission.^6,10 The indirect transmission of mpox via contaminated fomites is controversial, though some studies have shown the virus can survive on surfaces for up to 15 days.¹¹ In the current outbreak, human-to-human transmission has been strongly associated with close contact during sexual activity, particularly among men who have sex with men (MSM), with notable physical concentration of initial lesions in the genital region.¹² Anyone can acquire mpox—infections are not exclusive to MSM populations, and cases have been reported in all demographic groups, including women and children. It is important to avoid stigmatization of MSM to prevent the propagation of homophobia as well as a false sense of complacency in non-MSM populations.¹³

Clinical Presentation of Mpox

The incubation period of mpox has been reported to last up to 21 days and is posited to depend on the mode of transmission, with complex invasive exposures having a shorter duration of approximately 9 days compared to noninvasive exposures, which have a duration of approximately 13 days.¹⁴ In a recent report from the Netherlands, the average incubation time was 8.5 days in 18 men with exposure attributed to sexual encounters with men.¹² Following the incubation period, mpox infection typically presents with nonspecific systemic symptoms such as fever, malaise, sore throat, cough, and headache for approximately 2 days, followed by painful generalized or localized lymphadenopathy 1 to 2 days prior to the onset of skin lesions.^1,15 In a recent report from Portugal of more than 20 confirmed cases of mpox, approximately half of patients denied symptoms or had mild systemic symptoms, suggesting that many patients in the current outbreak do not endorse systemic symptoms.¹⁶

Classic cutaneous lesions are the hallmark feature of mpox.¹⁷ Over a period of 1 to 2 weeks, each lesion progresses through morphologic stages of macule, papule (Figure), vesicle, and pustule, which then crusts over, forming a scab that falls off after another 1 to 2 weeks and can result in dyspigmented or pitted scars.^1,15 Lesions may be deep-seated or umbilicated; previously they were noted to typically start on the face and spread centrifugally, but recent cases have been notable for a predominance of anogenital lesions, often with the anogenital area as the sole or primary area of involvement.¹⁸ Given the high proportion of anogenital lesions in 2022, symptoms such as anogenital pain, tenesmus, and diarrhea are not uncommon.¹⁹ A recent study describing 528 international cases of mpox revealed that 95% of patients presented with a rash; nearly 75% had anogenital lesions; and 41%, 25%, and 10% had involvement of mucosae, the face, and palms/soles, respectively. More than half of patients had fewer than 10 lesions, and 10% presented with a single genital lesion.¹⁹

Given the recent predilection of lesions for the anogenital area, the differential diagnosis of mpox should include other common infections localized to these areas. Unlike herpes simplex and varicella-zoster infections, mpox does not exhibit the classic herpetiform clustering of vesicles, and unlike the painless chancre of syphilis, the lesions of mpox are exquisitely painful. Similar to chancroid, mpox presents with painful genital lesions and lymphadenopathy, and the umbilicated papules of molluscum could easily be confused with mpox lesions. Proctitis caused by many sexually transmitted infections (STIs), including chlamydia and gonorrhea, may be difficult to differentiate from proctitis symptoms of mpox. Co-infection with HIV and other STIs is common among patients developing mpox in 2022, which is not surprising given that the primary mechanism of transmission of mpox at this time is through sexual contact, and cases are more common in patients with multiple recent sexual partners.¹⁹ Considering these shared risk factors and similar presentation of multiple STIs, patients suspected of having an mpox infection should be tested for other STIs, including HIV.

Complications of Mpox

Although mpox generally is characterized by a mild disease course, there is concern for adverse outcomes, particularly in more vulnerable populations, including immunocompromised, pregnant, and pediatric populations. Complications of infection can include sepsis, encephalitis, bronchopneumonia, and ophthalmic complications that can result in loss of vision.^6,17 The most common complications requiring hospitalization in a recent international report of 528 mpox cases were pain management, which was primarily due to severe anogenital pain, followed by soft-tissue superinfection, with other complications including severe pharyngitis limiting oral intake and infection control practices.¹⁹ In addition to severe rectal pain, proctitis and even rectal perforation have been reported.^19,20

Vertical transmission has been described with devastating outcomes in a case series from the Democratic Republic of Congo, where 4 cases of mpox were identified in pregnant women; 3 of these pregnancies resulted in fetal demise.¹⁰ The only fetus to survive was born to a mother with mild infection. In comparison, 2 of 3 mothers with moderate to severe disease experienced spontaneous abortion in the first trimester, and 1 pregnancy ended due to intrauterine demise during the eighteenth week of gestation, likely a complication of mpox. These cases suggest that more severe disease may be linked to worse fetal outcomes.¹⁰ Further epidemiologic studies will be crucial, given the potential implications.

Diagnosis

When considering a diagnosis of mpox, clinicians should inquire about recent travel, living arrangements, sexual history, and recent sick contacts.⁶ A complete skin examination should include the oral and genital areas, given the high prevalence of lesions in these areas. A skin biopsy is not recommended for the diagnosis of mpox, as nonspecific viral changes cannot be differentiated from other viral exanthems, but it often is useful to rule out other differential diagnoses.²¹ Additionally, immunohistochemistry and electron microscopy can be utilized to aid in a histologic diagnosis of mpox.

Polymerase chain reaction detection of orthopox or mpox DNA is the gold standard for diagnosis.⁶ Two swabs should be collected from each lesion by swabbing vigorously using sterile swabs made of a synthetic material such as polyester, nylon, or Dacron and placed into a sterile container or viral transport medium.²² Some laboratories may have different instructions for collection of samples, so clinicians are advised to check for instructions from their local laboratory. Deroofing lesions prior to swabbing is not necessary, and specimens can include lesional material or crust. Collection of specimens from 2 to 3 lesions is recommended, preferably from different body areas or lesions with varying morphologies. Anal or rectal swabs can be considered in patients presenting with anal pain or proctitis with clinical suspicion for mpox based on history.¹⁹

Infection Prevention

Interim guidance from the WHO on November 16, 2022, reiterated the goal of outbreak control primarily via public health measures, which includes targeted use of vaccines for at-risk populations or postexposure prophylactic vaccination within 4 days, but heavily relies on surveillance and containment techniques, such as contact tracing with monitoring of contacts for onset of symptoms and isolation of cases through the complete infectious period.²³ Patients are considered infectious from symptom onset until all cutaneous lesions are re-epithelized and should remain in isolation, including from household contacts and domestic and wildlife animals, for the duration of illness.^24,25 Individuals exposed to humans or animals with confirmed mpox should be monitored for the development of symptoms for 21 days following last known exposure, regardless of vaccination status, and should be instructed to measure their temperature twice daily.²⁶ Pets exposed to mpox should be isolated from other animals and humans for 21 days following last known contact.²⁴ Vaccination strategies for preexposure and postexposure prophylaxis (PEP) are discussed below in further detail. Postinfection, the WHO suggests use of condoms for all oral, vaginal, and anal sexual activity for 12 weeks after recovery.⁷

Patients with suspected or confirmed mpox in a hospital should be in a single private room on special droplet and contact precautions.²⁷ No special air handling or negative pressure isolation is needed unless the patient is undergoing an aerosol-generating procedure (eg, intubation, endoscopy, bronchoscopy). When hospitalized, patients should have a dedicated bathroom, if possible, and at-home patients should be isolated from household members until contagion risk resolves; this includes the use of a separate bathroom, when possible. Health care personnel entering the room of a patient should don appropriate personal protective equipment (PPE), including a disposable gown, gloves, eye protection, and N95 respirator or equivalent. Recommendations include standard practices for cleaning, with wet cleaning methods preferred over dry methods, using a disinfectant that covers emerging viral pathogens, and avoidance of shaking linens to prevent the spread of infectious particles.²⁷ A variety of Environmental Protection Agency–registered wipes with virucidal activity against emerging viruses, including those with active ingredients such as quaternary ammonium, hydrogen peroxide, and hypochlorous acid, should be used for disinfecting surfaces.²⁸

Vaccination

ACAM2000 (Emergent Bio Solutions) and JYNNEOS (Bavarian Nordic)(also known as Imvamune or Imvanex) are available in the United States for the prevention of mpox infection.²⁹ ACAM2000, a second-generation, replication-competent, live smallpox vaccine administered as a single percutaneous injection, is contraindicated in immunocompromised populations, including patients with HIV or on immunosuppressive or biologic therapy, pregnant individuals, people with a history of atopic dermatitis or other exfoliative skin diseases with impaired barrier function, and patients with a history of cardiac disease due to the risk of myocarditis and pericarditis.³⁰

JYNNEOS is a nonreplicating live vaccine approved by the US Food and Drug Administration (FDA) for the prevention of mpox in individuals older than 18 years administered as 2 subcutaneous doses 4 weeks apart. Patients are considered fully vaccinated 2 weeks after the second dose, and JYNNEOS is available to pediatric patients with a single patient expanded access use authorization from the FDA.^29,30 More recently, the FDA issued an emergency use authorization (EUA) for administration of the vaccine to patients younger than 18 years who are at high risk of infection after exposure.³¹ More importantly, the FDA also issued an EUA for the intradermal administration of JYNNEOS at one-fifth of the subcutaneous dose to expand the current vaccine supply. This EUA is based on research by Frey et al,³² which showed that intradermal administration, even at a lower dose, elicited similar immune responses among study participants as the higher dose administered subcutaneously.

JYNNEOS is the preferred vaccine for the prevention of mpox because of its poor ability to replicate in human cells and resultant safety for use in populations that are immunocompromised, pregnant, or have skin barrier defects such as atopic dermatitis, without the risk of myocarditis or pericarditis. However, current supplies are limited. JYNNEOS was specifically studied in patients with atopic dermatitis and has been shown to be safe and effective in patients with a history of atopic dermatitis and active disease with a SCORAD (SCORing Atopic Dermatitis) score of 30 or lower.³³ Of note, JYNNEOS is contraindicated in patients allergic to components of the vaccine, including egg, gentamicin, and ciprofloxacin. Although JYNNEOS is safe to administer to persons with immunocompromising conditions, the CDC reports that such persons might be at increased risk for severe disease if an occupational infection occurs, and in the setting of immunocompromise, such persons may be less likely to mount an effective response to vaccination. Therefore, the risk-benefit ratio should be considered to determine if an immunocompromised person should be vaccinated with JYNNEOS.³⁰

The WHO and the CDC do not recommended mass vaccination of the general public for outbreaks of mpox in nonendemic countries, with immunization reserved for appropriate PEP and pre-exposure prophylaxis in intermediate- to high-risk individuals.^23,26 The CDC recommends PEP vaccination for individuals with a high degree of exposure that includes unprotected contact of the skin or mucous membranes of an individual to the skin, lesions, body fluids, or contaminated fomites from a patient with mpox, as well as being within 6 feet of a patient during an aerosolization procedure without proper PPE. Following an intermediate degree of exposure, which includes being within 6 feet for 3 or more hours wearing at minimum a surgical mask or contact with fomites while wearing incomplete PPE, the CDC recommends monitoring and shared decision-making regarding risks and benefits of PEP vaccination. Monitoring without PEP is indicated for low and uncertain degrees of exposure, including entering a room without full PPE such as eye protection, regardless of the duration of contact.^23,26

Postexposure prophylaxis vaccination should be administered within 4 days of a known high-level exposure to mpox to prevent infection.²⁹ If administered within 4 to 14 days postexposure, vaccination may reduce disease severity but will not prevent infection.³⁴

Pre-exposure prophylaxis is recommended for individuals at high risk for exposure to mpox, including health care workers such as laboratory personnel who handle mpox specimens and health care workers who administer ACAM2000 vaccinations or anticipate providing care for many patients with mpox.³⁴

Management

Most cases of mpox are characterized by mild to moderate disease with a self-limited course. Most commonly, medical management of mpox involves supportive care such as fluid resuscitation, supplemental oxygen, and pain management.⁶ Treatment of superinfected skin lesions may require antibiotics. In the event of ophthalmologic involvement, patients should be referred to an ophthalmologist for further management.

Currently, there are no FDA-approved therapies for mpox; however, tecovirimat, cidofovir, brincidofovir, and vaccinia immune globulin intravenous are available under expanded access Investigational New Drug protocols.^6,35 Human data for cidofovir, brincidofovir, and vaccinia immune globulin intravenous in the treatment of mpox are lacking, while cidofovir and brincidofovir have shown efficacy against orthopoxviruses in in vitro and animal studies, but are available therapeutic options.³⁵

Tecovirimat is an antiviral that is FDA approved for smallpox with efficacy data against mpox in animal studies. It is the first-line treatment for patients with severe disease requiring hospitalization or 1 or more complications, including dehydration or secondary skin infections, as well as for populations at risk for severe disease, which includes immunocompromised patients, pediatric patients younger than 8 years, pregnant or breastfeeding individuals, or patients with a history of atopic dermatitis or active exfoliative skin conditions.³⁶ In this current outbreak, both intravenous and oral tecovirimat are weight based in adult and pediatric patients for 14 days, with the intravenous form dosed every 12 hours by infusion over 6 hours, and the oral doses administered every 8 to 12 hours based on patient weight.³⁷ Tecovirimat generally is well tolerated with mild side effects but is notably contraindicated in patients with severe renal impairment with a creatinine clearance less than 30 mL/min, and renal monitoring is indicated in pediatric patients younger than 2 years and in all patients receiving intravenous treatment.

Conclusion

Given that cutaneous lesions are the most specific presenting sign of mpox infection, dermatologists will play an integral role in identifying future cases and managing future outbreaks. Mpox should be considered in the differential diagnosis for all patients presenting with umbilicated or papulovesicular lesions, particularly in an anogenital distribution. The classic presentation of mpox may be more common among patients who are not considered high risk and have not been exposed via sexual activity. All patients with suspicious lesions should be managed following appropriate infection control precautions and should undergo molecular diagnostic assay of swabbed lesions to confirm the diagnosis. JYNNEOS is the only vaccine that is currently being distributed in the United States and is safe to administer to immunocompromised populations. The risks and benefits of vaccination should be considered on an individual basis between a patient and their provider. Taking into consideration that patients with atopic dermatitis are at risk for severe disease if infected with mpox, vaccination should be strongly encouraged if indicated based on patient risk factors. For atopic dermatitis patients treated with dupilumab, shared decision-making is essential given the FDA label, which recommends avoiding the use of live vaccines.³⁸

The mpox epidemic occurring amidst the ongoing COVID-19 pandemic should serve as a wake-up call to the importance of pandemic preparedness and the global health response strategies in the modern era of globalization. Looking forward, widespread vaccination against mpox may be necessary to control the spread of the disease and to protect vulnerable populations, including pregnant individuals. In the current climate of hesitancy surrounding vaccines and the erosion of trust in public health agencies, it is incumbent upon health care providers to educate patients regarding the role of vaccines and public health measures to control this developing global health crisis.

The mpox (monkeypox) virus is a zoonotic orthopox DNA virus that results in a smallpoxlike illness.¹ Vaccination against smallpox protects against other orthopox infections, including mpox; however, unlike smallpox, mpox is notable for a variety of not-yet-confirmed animal reservoirs.² Mpox was first identified in Denmark in 1959 among nonhuman primates imported from Singapore, and the first case of human infection was diagnosed in 1970 in a 9-month-old child in the Democratic Republic of Congo.³ Endemic regions of Africa have had sporadic outbreaks with increasing frequency over time since the cessation of smallpox vaccination in 1980.^2,4 Infections in nonendemic countries have occurred intermittently, including in 2003 in the Midwest United States. This outbreak was traced back to prairie dogs infected by exotic animals imported from the Republic of Ghana.⁵

Two genetic clades of mpox that differ in mortality rates have been identified: clade II (formerly the West African clade) generally is self-limited with an estimated mortality of 1% to 6%, whereas clade I (formerly the Congo Basin clade) is more transmissible, with a mortality of approximately 10%.^2,6,7 Notably, as of May 2, 2022, all polymerase chain reaction–confirmed cases of mpox in nonendemic countries were identified as clade II.⁷ Following the continued international spread of mpox, the Director-General of the World Health Organization (WHO) declared the global outbreak a public health emergency of international concern on July 23, 2022.⁸ As of March 1, 2023, the Centers for Disease Control and Prevention (CDC) reports that there have been more than 86,000 cases of laboratory-confirmed mpox worldwide and 105 deaths, 89 of which occurred in nonendemic regions.⁹

Transmission of Mpox

In endemic countries, cases have been largely reported secondary to zoonotic spillover from contact with an infected animal.⁶ However, in nonendemic countries, mpox often results from human-to-human transmission, primarily via skin-to-skin contact with infected skin, but also may occur indirectly via contaminated fomites such as bedding or clothing, respiratory secretions, or vertical transmission.^6,10 The indirect transmission of mpox via contaminated fomites is controversial, though some studies have shown the virus can survive on surfaces for up to 15 days.¹¹ In the current outbreak, human-to-human transmission has been strongly associated with close contact during sexual activity, particularly among men who have sex with men (MSM), with notable physical concentration of initial lesions in the genital region.¹² Anyone can acquire mpox—infections are not exclusive to MSM populations, and cases have been reported in all demographic groups, including women and children. It is important to avoid stigmatization of MSM to prevent the propagation of homophobia as well as a false sense of complacency in non-MSM populations.¹³

Clinical Presentation of Mpox

The incubation period of mpox has been reported to last up to 21 days and is posited to depend on the mode of transmission, with complex invasive exposures having a shorter duration of approximately 9 days compared to noninvasive exposures, which have a duration of approximately 13 days.¹⁴ In a recent report from the Netherlands, the average incubation time was 8.5 days in 18 men with exposure attributed to sexual encounters with men.¹² Following the incubation period, mpox infection typically presents with nonspecific systemic symptoms such as fever, malaise, sore throat, cough, and headache for approximately 2 days, followed by painful generalized or localized lymphadenopathy 1 to 2 days prior to the onset of skin lesions.^1,15 In a recent report from Portugal of more than 20 confirmed cases of mpox, approximately half of patients denied symptoms or had mild systemic symptoms, suggesting that many patients in the current outbreak do not endorse systemic symptoms.¹⁶

Classic cutaneous lesions are the hallmark feature of mpox.¹⁷ Over a period of 1 to 2 weeks, each lesion progresses through morphologic stages of macule, papule (Figure), vesicle, and pustule, which then crusts over, forming a scab that falls off after another 1 to 2 weeks and can result in dyspigmented or pitted scars.^1,15 Lesions may be deep-seated or umbilicated; previously they were noted to typically start on the face and spread centrifugally, but recent cases have been notable for a predominance of anogenital lesions, often with the anogenital area as the sole or primary area of involvement.¹⁸ Given the high proportion of anogenital lesions in 2022, symptoms such as anogenital pain, tenesmus, and diarrhea are not uncommon.¹⁹ A recent study describing 528 international cases of mpox revealed that 95% of patients presented with a rash; nearly 75% had anogenital lesions; and 41%, 25%, and 10% had involvement of mucosae, the face, and palms/soles, respectively. More than half of patients had fewer than 10 lesions, and 10% presented with a single genital lesion.¹⁹

Given the recent predilection of lesions for the anogenital area, the differential diagnosis of mpox should include other common infections localized to these areas. Unlike herpes simplex and varicella-zoster infections, mpox does not exhibit the classic herpetiform clustering of vesicles, and unlike the painless chancre of syphilis, the lesions of mpox are exquisitely painful. Similar to chancroid, mpox presents with painful genital lesions and lymphadenopathy, and the umbilicated papules of molluscum could easily be confused with mpox lesions. Proctitis caused by many sexually transmitted infections (STIs), including chlamydia and gonorrhea, may be difficult to differentiate from proctitis symptoms of mpox. Co-infection with HIV and other STIs is common among patients developing mpox in 2022, which is not surprising given that the primary mechanism of transmission of mpox at this time is through sexual contact, and cases are more common in patients with multiple recent sexual partners.¹⁹ Considering these shared risk factors and similar presentation of multiple STIs, patients suspected of having an mpox infection should be tested for other STIs, including HIV.

Complications of Mpox

Although mpox generally is characterized by a mild disease course, there is concern for adverse outcomes, particularly in more vulnerable populations, including immunocompromised, pregnant, and pediatric populations. Complications of infection can include sepsis, encephalitis, bronchopneumonia, and ophthalmic complications that can result in loss of vision.^6,17 The most common complications requiring hospitalization in a recent international report of 528 mpox cases were pain management, which was primarily due to severe anogenital pain, followed by soft-tissue superinfection, with other complications including severe pharyngitis limiting oral intake and infection control practices.¹⁹ In addition to severe rectal pain, proctitis and even rectal perforation have been reported.^19,20

Vertical transmission has been described with devastating outcomes in a case series from the Democratic Republic of Congo, where 4 cases of mpox were identified in pregnant women; 3 of these pregnancies resulted in fetal demise.¹⁰ The only fetus to survive was born to a mother with mild infection. In comparison, 2 of 3 mothers with moderate to severe disease experienced spontaneous abortion in the first trimester, and 1 pregnancy ended due to intrauterine demise during the eighteenth week of gestation, likely a complication of mpox. These cases suggest that more severe disease may be linked to worse fetal outcomes.¹⁰ Further epidemiologic studies will be crucial, given the potential implications.

Diagnosis

When considering a diagnosis of mpox, clinicians should inquire about recent travel, living arrangements, sexual history, and recent sick contacts.⁶ A complete skin examination should include the oral and genital areas, given the high prevalence of lesions in these areas. A skin biopsy is not recommended for the diagnosis of mpox, as nonspecific viral changes cannot be differentiated from other viral exanthems, but it often is useful to rule out other differential diagnoses.²¹ Additionally, immunohistochemistry and electron microscopy can be utilized to aid in a histologic diagnosis of mpox.

Polymerase chain reaction detection of orthopox or mpox DNA is the gold standard for diagnosis.⁶ Two swabs should be collected from each lesion by swabbing vigorously using sterile swabs made of a synthetic material such as polyester, nylon, or Dacron and placed into a sterile container or viral transport medium.²² Some laboratories may have different instructions for collection of samples, so clinicians are advised to check for instructions from their local laboratory. Deroofing lesions prior to swabbing is not necessary, and specimens can include lesional material or crust. Collection of specimens from 2 to 3 lesions is recommended, preferably from different body areas or lesions with varying morphologies. Anal or rectal swabs can be considered in patients presenting with anal pain or proctitis with clinical suspicion for mpox based on history.¹⁹

Infection Prevention

Interim guidance from the WHO on November 16, 2022, reiterated the goal of outbreak control primarily via public health measures, which includes targeted use of vaccines for at-risk populations or postexposure prophylactic vaccination within 4 days, but heavily relies on surveillance and containment techniques, such as contact tracing with monitoring of contacts for onset of symptoms and isolation of cases through the complete infectious period.²³ Patients are considered infectious from symptom onset until all cutaneous lesions are re-epithelized and should remain in isolation, including from household contacts and domestic and wildlife animals, for the duration of illness.^24,25 Individuals exposed to humans or animals with confirmed mpox should be monitored for the development of symptoms for 21 days following last known exposure, regardless of vaccination status, and should be instructed to measure their temperature twice daily.²⁶ Pets exposed to mpox should be isolated from other animals and humans for 21 days following last known contact.²⁴ Vaccination strategies for preexposure and postexposure prophylaxis (PEP) are discussed below in further detail. Postinfection, the WHO suggests use of condoms for all oral, vaginal, and anal sexual activity for 12 weeks after recovery.⁷

Patients with suspected or confirmed mpox in a hospital should be in a single private room on special droplet and contact precautions.²⁷ No special air handling or negative pressure isolation is needed unless the patient is undergoing an aerosol-generating procedure (eg, intubation, endoscopy, bronchoscopy). When hospitalized, patients should have a dedicated bathroom, if possible, and at-home patients should be isolated from household members until contagion risk resolves; this includes the use of a separate bathroom, when possible. Health care personnel entering the room of a patient should don appropriate personal protective equipment (PPE), including a disposable gown, gloves, eye protection, and N95 respirator or equivalent. Recommendations include standard practices for cleaning, with wet cleaning methods preferred over dry methods, using a disinfectant that covers emerging viral pathogens, and avoidance of shaking linens to prevent the spread of infectious particles.²⁷ A variety of Environmental Protection Agency–registered wipes with virucidal activity against emerging viruses, including those with active ingredients such as quaternary ammonium, hydrogen peroxide, and hypochlorous acid, should be used for disinfecting surfaces.²⁸

Vaccination

ACAM2000 (Emergent Bio Solutions) and JYNNEOS (Bavarian Nordic)(also known as Imvamune or Imvanex) are available in the United States for the prevention of mpox infection.²⁹ ACAM2000, a second-generation, replication-competent, live smallpox vaccine administered as a single percutaneous injection, is contraindicated in immunocompromised populations, including patients with HIV or on immunosuppressive or biologic therapy, pregnant individuals, people with a history of atopic dermatitis or other exfoliative skin diseases with impaired barrier function, and patients with a history of cardiac disease due to the risk of myocarditis and pericarditis.³⁰

JYNNEOS is a nonreplicating live vaccine approved by the US Food and Drug Administration (FDA) for the prevention of mpox in individuals older than 18 years administered as 2 subcutaneous doses 4 weeks apart. Patients are considered fully vaccinated 2 weeks after the second dose, and JYNNEOS is available to pediatric patients with a single patient expanded access use authorization from the FDA.^29,30 More recently, the FDA issued an emergency use authorization (EUA) for administration of the vaccine to patients younger than 18 years who are at high risk of infection after exposure.³¹ More importantly, the FDA also issued an EUA for the intradermal administration of JYNNEOS at one-fifth of the subcutaneous dose to expand the current vaccine supply. This EUA is based on research by Frey et al,³² which showed that intradermal administration, even at a lower dose, elicited similar immune responses among study participants as the higher dose administered subcutaneously.

JYNNEOS is the preferred vaccine for the prevention of mpox because of its poor ability to replicate in human cells and resultant safety for use in populations that are immunocompromised, pregnant, or have skin barrier defects such as atopic dermatitis, without the risk of myocarditis or pericarditis. However, current supplies are limited. JYNNEOS was specifically studied in patients with atopic dermatitis and has been shown to be safe and effective in patients with a history of atopic dermatitis and active disease with a SCORAD (SCORing Atopic Dermatitis) score of 30 or lower.³³ Of note, JYNNEOS is contraindicated in patients allergic to components of the vaccine, including egg, gentamicin, and ciprofloxacin. Although JYNNEOS is safe to administer to persons with immunocompromising conditions, the CDC reports that such persons might be at increased risk for severe disease if an occupational infection occurs, and in the setting of immunocompromise, such persons may be less likely to mount an effective response to vaccination. Therefore, the risk-benefit ratio should be considered to determine if an immunocompromised person should be vaccinated with JYNNEOS.³⁰

The WHO and the CDC do not recommended mass vaccination of the general public for outbreaks of mpox in nonendemic countries, with immunization reserved for appropriate PEP and pre-exposure prophylaxis in intermediate- to high-risk individuals.^23,26 The CDC recommends PEP vaccination for individuals with a high degree of exposure that includes unprotected contact of the skin or mucous membranes of an individual to the skin, lesions, body fluids, or contaminated fomites from a patient with mpox, as well as being within 6 feet of a patient during an aerosolization procedure without proper PPE. Following an intermediate degree of exposure, which includes being within 6 feet for 3 or more hours wearing at minimum a surgical mask or contact with fomites while wearing incomplete PPE, the CDC recommends monitoring and shared decision-making regarding risks and benefits of PEP vaccination. Monitoring without PEP is indicated for low and uncertain degrees of exposure, including entering a room without full PPE such as eye protection, regardless of the duration of contact.^23,26

Postexposure prophylaxis vaccination should be administered within 4 days of a known high-level exposure to mpox to prevent infection.²⁹ If administered within 4 to 14 days postexposure, vaccination may reduce disease severity but will not prevent infection.³⁴

Pre-exposure prophylaxis is recommended for individuals at high risk for exposure to mpox, including health care workers such as laboratory personnel who handle mpox specimens and health care workers who administer ACAM2000 vaccinations or anticipate providing care for many patients with mpox.³⁴

Management

Most cases of mpox are characterized by mild to moderate disease with a self-limited course. Most commonly, medical management of mpox involves supportive care such as fluid resuscitation, supplemental oxygen, and pain management.⁶ Treatment of superinfected skin lesions may require antibiotics. In the event of ophthalmologic involvement, patients should be referred to an ophthalmologist for further management.

Currently, there are no FDA-approved therapies for mpox; however, tecovirimat, cidofovir, brincidofovir, and vaccinia immune globulin intravenous are available under expanded access Investigational New Drug protocols.^6,35 Human data for cidofovir, brincidofovir, and vaccinia immune globulin intravenous in the treatment of mpox are lacking, while cidofovir and brincidofovir have shown efficacy against orthopoxviruses in in vitro and animal studies, but are available therapeutic options.³⁵

Tecovirimat is an antiviral that is FDA approved for smallpox with efficacy data against mpox in animal studies. It is the first-line treatment for patients with severe disease requiring hospitalization or 1 or more complications, including dehydration or secondary skin infections, as well as for populations at risk for severe disease, which includes immunocompromised patients, pediatric patients younger than 8 years, pregnant or breastfeeding individuals, or patients with a history of atopic dermatitis or active exfoliative skin conditions.³⁶ In this current outbreak, both intravenous and oral tecovirimat are weight based in adult and pediatric patients for 14 days, with the intravenous form dosed every 12 hours by infusion over 6 hours, and the oral doses administered every 8 to 12 hours based on patient weight.³⁷ Tecovirimat generally is well tolerated with mild side effects but is notably contraindicated in patients with severe renal impairment with a creatinine clearance less than 30 mL/min, and renal monitoring is indicated in pediatric patients younger than 2 years and in all patients receiving intravenous treatment.

Conclusion

Given that cutaneous lesions are the most specific presenting sign of mpox infection, dermatologists will play an integral role in identifying future cases and managing future outbreaks. Mpox should be considered in the differential diagnosis for all patients presenting with umbilicated or papulovesicular lesions, particularly in an anogenital distribution. The classic presentation of mpox may be more common among patients who are not considered high risk and have not been exposed via sexual activity. All patients with suspicious lesions should be managed following appropriate infection control precautions and should undergo molecular diagnostic assay of swabbed lesions to confirm the diagnosis. JYNNEOS is the only vaccine that is currently being distributed in the United States and is safe to administer to immunocompromised populations. The risks and benefits of vaccination should be considered on an individual basis between a patient and their provider. Taking into consideration that patients with atopic dermatitis are at risk for severe disease if infected with mpox, vaccination should be strongly encouraged if indicated based on patient risk factors. For atopic dermatitis patients treated with dupilumab, shared decision-making is essential given the FDA label, which recommends avoiding the use of live vaccines.³⁸

The mpox epidemic occurring amidst the ongoing COVID-19 pandemic should serve as a wake-up call to the importance of pandemic preparedness and the global health response strategies in the modern era of globalization. Looking forward, widespread vaccination against mpox may be necessary to control the spread of the disease and to protect vulnerable populations, including pregnant individuals. In the current climate of hesitancy surrounding vaccines and the erosion of trust in public health agencies, it is incumbent upon health care providers to educate patients regarding the role of vaccines and public health measures to control this developing global health crisis.

High-dose prophylactic anticoagulation or therapeutic anticoagulation reduced de novo thrombosis in patients with hypoxemic COVID-19 pneumonia, based on data from 334 adults.

Patients with hypoxemic COVID-19 pneumonia are at increased risk of thrombosis and anticoagulation-related bleeding, therefore data to identify the lowest effective anticoagulant dose are needed, wrote Vincent Labbé, MD, of Sorbonne University, Paris, and colleagues.

Previous studies of different anticoagulation strategies for noncritically ill and critically ill patients with COVID-19 pneumonia have shown contrasting results, but some institutions recommend a high-dose regimen in the wake of data showing macrovascular thrombosis in patients with COVID-19 who were treated with standard anticoagulation, the authors wrote.

However, no previously published studies have compared the effectiveness of the three anticoagulation strategies: high-dose prophylactic anticoagulation (HD-PA), standard dose prophylactic anticoagulation (SD-PA), and therapeutic anticoagulation (TA), they said.

In the open-label Anticoagulation COVID-19 (ANTICOVID) trial, published in JAMA Internal Medicine, the researchers identified consecutively hospitalized adults aged 18 years and older being treated for hypoxemic COVID-19 pneumonia in 23 centers in France between April 2021 and December 2021.

The patients were randomly assigned to SD-PA (116 patients), HD-PA (111 patients), and TA (112 patients) using low-molecular-weight heparin for 14 days, or until either hospital discharge or weaning from supplemental oxygen for 48 consecutive hours, whichever outcome occurred first.  The HD-PA patients received two times the SD-PA dose. The mean age of the patients was 58.3 years, and approximately two-thirds were men; race and ethnicity data were not collected. Participants had no macrovascular thrombosis at the start of the study.

The primary outcomes were all-cause mortality and time to clinical improvement (defined as the time from randomization to a 2-point improvement on a 7-category respiratory function scale).

The secondary outcome was a combination of safety and efficacy at day 28 that included a composite of thrombosis (ischemic stroke, noncerebrovascular arterial thrombosis, deep venous thrombosis, pulmonary artery thrombosis, and central venous catheter–related deep venous thrombosis), major bleeding, or all-cause death.

For the primary outcome, results were similar among the groups; HD-PA had no significant benefit over SD-PA or TA. All-cause death rates for SD-PA, HD-PA, and TA patients were 14%, 12%, and 13%, respectively. The time to clinical improvement for the three groups was approximately 8 days, 9 days, and 8 days, respectively. Results for the primary outcome were consistent across all prespecified subgroups.

However, HD-PA was associated with a significant fourfold reduced risk of de novo thrombosis compared with SD-PA (5.5% vs. 20.2%) with no observed increase in major bleeding. TA was not associated with any significant improvement in primary or secondary outcomes compared with HD-PA or SD-PA.

The current study findings of no improvement in survival or disease resolution in patients with a higher anticoagulant dose reflects data from previous studies, the researchers wrote in their discussion. “Our study results together with those of previous RCTs support the premise that the role of microvascular thrombosis in worsening organ dysfunction may be narrower than estimated,” they said.

The findings were limited by several factors including the open-label design and the relatively small sample size, the lack of data on microvascular (vs. macrovascular) thrombosis at baseline, and the predominance of the Delta variant of COVID-19 among the study participants, which may have contributed to a lower mortality rate, the researchers noted.

However, given the significant reduction in de novo thrombosis, the results support the routine use of HD-PA in patients with severe hypoxemic COVID-19 pneumonia, they concluded.
 

Results inform current clinical practice

Over the course of the COVID-19 pandemic, “Patients hospitalized with COVID-19 manifested the highest risk for thromboembolic complications, especially patients in the intensive care setting,” and early reports suggested that standard prophylactic doses of anticoagulant therapy might be insufficient to prevent thrombotic events, Richard C. Becker, MD, of the University of Cincinnati, and Thomas L. Ortel, MD, of Duke University, Durham, N.C., wrote in an accompanying editorial.

“Although there have been several studies that have investigated the role of anticoagulant therapy in hospitalized patients with COVID-19, this is the first study that specifically compared a standard, prophylactic dose of low-molecular-weight heparin to a ‘high-dose’ prophylactic regimen and to a full therapeutic dose regimen,” Dr. Ortel said in an interview.

“Given the concerns about an increased thrombotic risk with prophylactic dose anticoagulation, and the potential bleeding risk associated with a full therapeutic dose of anticoagulation, this approach enabled the investigators to explore the efficacy and safety of an intermediate dose between these two extremes,” he said.

In the current study, “It was notable that the primary driver of the improved outcomes with the ‘high-dose’ prophylactic regimen reflected the fourfold reduction in macrovascular thrombosis, a finding that was not observed in other studies investigating anticoagulant therapy in hospitalized patients with severe COVID-19,” Dr. Ortel told this news organization. “Much initial concern about progression of disease in patients hospitalized with severe COVID-19 focused on the role of microvascular thrombosis, which appears to be less important in this process, or, alternatively, less responsive to anticoagulant therapy.”

The clinical takeaway from the study, Dr. Ortel said, is the decreased risk for venous thromboembolism with a high-dose prophylactic anticoagulation strategy compared with a standard-dose prophylactic regimen for patients hospitalized with hypoxemic COVID-19 pneumonia, “leading to an improved net clinical outcome.”

Looking ahead, “Additional research is needed to determine whether a higher dose of prophylactic anticoagulation would be beneficial for patients hospitalized with COVID-19 pneumonia who are not in an intensive care unit setting,” Dr. Ortel said. Studies are needed to determine whether therapeutic interventions are equally beneficial in patients with different coronavirus variants, since most patients in the current study were infected with the Delta variant, he added.

The study was supported by LEO Pharma. Dr. Labbé disclosed grants from LEO Pharma during the study and fees from AOP Health unrelated to the current study.

Dr. Becker disclosed personal fees from Novartis Data Safety Monitoring Board, Ionis Data Safety Monitoring Board, and Basking Biosciences Scientific Advisory Board unrelated to the current study. Dr. Ortel disclosed grants from the National Institutes of Health, Instrumentation Laboratory, Stago, and Siemens; contract fees from the Centers for Disease Control and Prevention; and honoraria from UpToDate unrelated to the current study.
 

A version of this article originally appeared on Medscape.com.

High-dose prophylactic anticoagulation or therapeutic anticoagulation reduced de novo thrombosis in patients with hypoxemic COVID-19 pneumonia, based on data from 334 adults.

Patients with hypoxemic COVID-19 pneumonia are at increased risk of thrombosis and anticoagulation-related bleeding, therefore data to identify the lowest effective anticoagulant dose are needed, wrote Vincent Labbé, MD, of Sorbonne University, Paris, and colleagues.

Previous studies of different anticoagulation strategies for noncritically ill and critically ill patients with COVID-19 pneumonia have shown contrasting results, but some institutions recommend a high-dose regimen in the wake of data showing macrovascular thrombosis in patients with COVID-19 who were treated with standard anticoagulation, the authors wrote.

However, no previously published studies have compared the effectiveness of the three anticoagulation strategies: high-dose prophylactic anticoagulation (HD-PA), standard dose prophylactic anticoagulation (SD-PA), and therapeutic anticoagulation (TA), they said.

In the open-label Anticoagulation COVID-19 (ANTICOVID) trial, published in JAMA Internal Medicine, the researchers identified consecutively hospitalized adults aged 18 years and older being treated for hypoxemic COVID-19 pneumonia in 23 centers in France between April 2021 and December 2021.

The patients were randomly assigned to SD-PA (116 patients), HD-PA (111 patients), and TA (112 patients) using low-molecular-weight heparin for 14 days, or until either hospital discharge or weaning from supplemental oxygen for 48 consecutive hours, whichever outcome occurred first.  The HD-PA patients received two times the SD-PA dose. The mean age of the patients was 58.3 years, and approximately two-thirds were men; race and ethnicity data were not collected. Participants had no macrovascular thrombosis at the start of the study.

The primary outcomes were all-cause mortality and time to clinical improvement (defined as the time from randomization to a 2-point improvement on a 7-category respiratory function scale).

The secondary outcome was a combination of safety and efficacy at day 28 that included a composite of thrombosis (ischemic stroke, noncerebrovascular arterial thrombosis, deep venous thrombosis, pulmonary artery thrombosis, and central venous catheter–related deep venous thrombosis), major bleeding, or all-cause death.

For the primary outcome, results were similar among the groups; HD-PA had no significant benefit over SD-PA or TA. All-cause death rates for SD-PA, HD-PA, and TA patients were 14%, 12%, and 13%, respectively. The time to clinical improvement for the three groups was approximately 8 days, 9 days, and 8 days, respectively. Results for the primary outcome were consistent across all prespecified subgroups.

However, HD-PA was associated with a significant fourfold reduced risk of de novo thrombosis compared with SD-PA (5.5% vs. 20.2%) with no observed increase in major bleeding. TA was not associated with any significant improvement in primary or secondary outcomes compared with HD-PA or SD-PA.

The current study findings of no improvement in survival or disease resolution in patients with a higher anticoagulant dose reflects data from previous studies, the researchers wrote in their discussion. “Our study results together with those of previous RCTs support the premise that the role of microvascular thrombosis in worsening organ dysfunction may be narrower than estimated,” they said.

The findings were limited by several factors including the open-label design and the relatively small sample size, the lack of data on microvascular (vs. macrovascular) thrombosis at baseline, and the predominance of the Delta variant of COVID-19 among the study participants, which may have contributed to a lower mortality rate, the researchers noted.

However, given the significant reduction in de novo thrombosis, the results support the routine use of HD-PA in patients with severe hypoxemic COVID-19 pneumonia, they concluded.
 

Results inform current clinical practice

Over the course of the COVID-19 pandemic, “Patients hospitalized with COVID-19 manifested the highest risk for thromboembolic complications, especially patients in the intensive care setting,” and early reports suggested that standard prophylactic doses of anticoagulant therapy might be insufficient to prevent thrombotic events, Richard C. Becker, MD, of the University of Cincinnati, and Thomas L. Ortel, MD, of Duke University, Durham, N.C., wrote in an accompanying editorial.

“Although there have been several studies that have investigated the role of anticoagulant therapy in hospitalized patients with COVID-19, this is the first study that specifically compared a standard, prophylactic dose of low-molecular-weight heparin to a ‘high-dose’ prophylactic regimen and to a full therapeutic dose regimen,” Dr. Ortel said in an interview.

“Given the concerns about an increased thrombotic risk with prophylactic dose anticoagulation, and the potential bleeding risk associated with a full therapeutic dose of anticoagulation, this approach enabled the investigators to explore the efficacy and safety of an intermediate dose between these two extremes,” he said.

In the current study, “It was notable that the primary driver of the improved outcomes with the ‘high-dose’ prophylactic regimen reflected the fourfold reduction in macrovascular thrombosis, a finding that was not observed in other studies investigating anticoagulant therapy in hospitalized patients with severe COVID-19,” Dr. Ortel told this news organization. “Much initial concern about progression of disease in patients hospitalized with severe COVID-19 focused on the role of microvascular thrombosis, which appears to be less important in this process, or, alternatively, less responsive to anticoagulant therapy.”

The clinical takeaway from the study, Dr. Ortel said, is the decreased risk for venous thromboembolism with a high-dose prophylactic anticoagulation strategy compared with a standard-dose prophylactic regimen for patients hospitalized with hypoxemic COVID-19 pneumonia, “leading to an improved net clinical outcome.”

Looking ahead, “Additional research is needed to determine whether a higher dose of prophylactic anticoagulation would be beneficial for patients hospitalized with COVID-19 pneumonia who are not in an intensive care unit setting,” Dr. Ortel said. Studies are needed to determine whether therapeutic interventions are equally beneficial in patients with different coronavirus variants, since most patients in the current study were infected with the Delta variant, he added.

The study was supported by LEO Pharma. Dr. Labbé disclosed grants from LEO Pharma during the study and fees from AOP Health unrelated to the current study.

Dr. Becker disclosed personal fees from Novartis Data Safety Monitoring Board, Ionis Data Safety Monitoring Board, and Basking Biosciences Scientific Advisory Board unrelated to the current study. Dr. Ortel disclosed grants from the National Institutes of Health, Instrumentation Laboratory, Stago, and Siemens; contract fees from the Centers for Disease Control and Prevention; and honoraria from UpToDate unrelated to the current study.
 

A version of this article originally appeared on Medscape.com.

High-dose prophylactic anticoagulation or therapeutic anticoagulation reduced de novo thrombosis in patients with hypoxemic COVID-19 pneumonia, based on data from 334 adults.

Patients with hypoxemic COVID-19 pneumonia are at increased risk of thrombosis and anticoagulation-related bleeding, therefore data to identify the lowest effective anticoagulant dose are needed, wrote Vincent Labbé, MD, of Sorbonne University, Paris, and colleagues.

Previous studies of different anticoagulation strategies for noncritically ill and critically ill patients with COVID-19 pneumonia have shown contrasting results, but some institutions recommend a high-dose regimen in the wake of data showing macrovascular thrombosis in patients with COVID-19 who were treated with standard anticoagulation, the authors wrote.

However, no previously published studies have compared the effectiveness of the three anticoagulation strategies: high-dose prophylactic anticoagulation (HD-PA), standard dose prophylactic anticoagulation (SD-PA), and therapeutic anticoagulation (TA), they said.

In the open-label Anticoagulation COVID-19 (ANTICOVID) trial, published in JAMA Internal Medicine, the researchers identified consecutively hospitalized adults aged 18 years and older being treated for hypoxemic COVID-19 pneumonia in 23 centers in France between April 2021 and December 2021.

The patients were randomly assigned to SD-PA (116 patients), HD-PA (111 patients), and TA (112 patients) using low-molecular-weight heparin for 14 days, or until either hospital discharge or weaning from supplemental oxygen for 48 consecutive hours, whichever outcome occurred first.  The HD-PA patients received two times the SD-PA dose. The mean age of the patients was 58.3 years, and approximately two-thirds were men; race and ethnicity data were not collected. Participants had no macrovascular thrombosis at the start of the study.

The primary outcomes were all-cause mortality and time to clinical improvement (defined as the time from randomization to a 2-point improvement on a 7-category respiratory function scale).

The secondary outcome was a combination of safety and efficacy at day 28 that included a composite of thrombosis (ischemic stroke, noncerebrovascular arterial thrombosis, deep venous thrombosis, pulmonary artery thrombosis, and central venous catheter–related deep venous thrombosis), major bleeding, or all-cause death.

For the primary outcome, results were similar among the groups; HD-PA had no significant benefit over SD-PA or TA. All-cause death rates for SD-PA, HD-PA, and TA patients were 14%, 12%, and 13%, respectively. The time to clinical improvement for the three groups was approximately 8 days, 9 days, and 8 days, respectively. Results for the primary outcome were consistent across all prespecified subgroups.

However, HD-PA was associated with a significant fourfold reduced risk of de novo thrombosis compared with SD-PA (5.5% vs. 20.2%) with no observed increase in major bleeding. TA was not associated with any significant improvement in primary or secondary outcomes compared with HD-PA or SD-PA.

The current study findings of no improvement in survival or disease resolution in patients with a higher anticoagulant dose reflects data from previous studies, the researchers wrote in their discussion. “Our study results together with those of previous RCTs support the premise that the role of microvascular thrombosis in worsening organ dysfunction may be narrower than estimated,” they said.

The findings were limited by several factors including the open-label design and the relatively small sample size, the lack of data on microvascular (vs. macrovascular) thrombosis at baseline, and the predominance of the Delta variant of COVID-19 among the study participants, which may have contributed to a lower mortality rate, the researchers noted.

However, given the significant reduction in de novo thrombosis, the results support the routine use of HD-PA in patients with severe hypoxemic COVID-19 pneumonia, they concluded.
 

Results inform current clinical practice

Over the course of the COVID-19 pandemic, “Patients hospitalized with COVID-19 manifested the highest risk for thromboembolic complications, especially patients in the intensive care setting,” and early reports suggested that standard prophylactic doses of anticoagulant therapy might be insufficient to prevent thrombotic events, Richard C. Becker, MD, of the University of Cincinnati, and Thomas L. Ortel, MD, of Duke University, Durham, N.C., wrote in an accompanying editorial.

“Although there have been several studies that have investigated the role of anticoagulant therapy in hospitalized patients with COVID-19, this is the first study that specifically compared a standard, prophylactic dose of low-molecular-weight heparin to a ‘high-dose’ prophylactic regimen and to a full therapeutic dose regimen,” Dr. Ortel said in an interview.

“Given the concerns about an increased thrombotic risk with prophylactic dose anticoagulation, and the potential bleeding risk associated with a full therapeutic dose of anticoagulation, this approach enabled the investigators to explore the efficacy and safety of an intermediate dose between these two extremes,” he said.

In the current study, “It was notable that the primary driver of the improved outcomes with the ‘high-dose’ prophylactic regimen reflected the fourfold reduction in macrovascular thrombosis, a finding that was not observed in other studies investigating anticoagulant therapy in hospitalized patients with severe COVID-19,” Dr. Ortel told this news organization. “Much initial concern about progression of disease in patients hospitalized with severe COVID-19 focused on the role of microvascular thrombosis, which appears to be less important in this process, or, alternatively, less responsive to anticoagulant therapy.”

The clinical takeaway from the study, Dr. Ortel said, is the decreased risk for venous thromboembolism with a high-dose prophylactic anticoagulation strategy compared with a standard-dose prophylactic regimen for patients hospitalized with hypoxemic COVID-19 pneumonia, “leading to an improved net clinical outcome.”

Looking ahead, “Additional research is needed to determine whether a higher dose of prophylactic anticoagulation would be beneficial for patients hospitalized with COVID-19 pneumonia who are not in an intensive care unit setting,” Dr. Ortel said. Studies are needed to determine whether therapeutic interventions are equally beneficial in patients with different coronavirus variants, since most patients in the current study were infected with the Delta variant, he added.

The study was supported by LEO Pharma. Dr. Labbé disclosed grants from LEO Pharma during the study and fees from AOP Health unrelated to the current study.

Dr. Becker disclosed personal fees from Novartis Data Safety Monitoring Board, Ionis Data Safety Monitoring Board, and Basking Biosciences Scientific Advisory Board unrelated to the current study. Dr. Ortel disclosed grants from the National Institutes of Health, Instrumentation Laboratory, Stago, and Siemens; contract fees from the Centers for Disease Control and Prevention; and honoraria from UpToDate unrelated to the current study.
 

A version of this article originally appeared on Medscape.com.

To the Editor:

The organisms of the genus Nocardia are gram-positive, ubiquitous, aerobic actinomycetes found worldwide in soil, decaying organic material, and water.¹ The genus Nocardia includes more than 50 species; some species, such as Nocardia asteroides, Nocardia farcinica, Nocardia nova, and Nocardia brasiliensis, are the cause of nocardiosis in humans and animals.^2,3 Nocardiosis is a rare and opportunistic infection that predominantly affects immunocompromised individuals; however, up to 30% of infections can occur in immunocompetent hosts.⁴ Nocardiosis can manifest in 3 disease forms: cutaneous, pulmonary, or disseminated. Cutaneous nocardiosis commonly develops in immunocompetent individuals who have experienced a predisposing traumatic injury to the skin,⁵ and it can exhibit a diverse variety of clinical manifestations, making diagnosis difficult. We describe a case of serious progressive primary cutaneous nocardiosis with an unusual presentation in an immunocompetent patient.

A 26-year-old immunocompetent man presented with pain, swelling, nodules, abscesses, ulcers, and sinus drainage of the left arm. The left elbow lesion initially developed at the site of a trauma 6 years prior that was painless but was contaminated with mossy soil. The condition slowly progressed over the next 2 years, and the patient experienced increased swelling and eventually developed multiple draining sinus tracts. Over the next 4 years, the lesions multiplied, spreading to the forearm and upper arm; associated severe pain and swelling at the elbow and wrist joint developed. The patient sought medical care at a local hospital and subsequently was diagnosed with suspected cutaneous tuberculosis. The patient was empirically treated with a 6-month course of isoniazid, rifampicin, pyrazinamide, and ethambutol; however, the lesions continued to progress and worsen. The patient had to stop antibiotic treatment because of substantially elevated alanine aminotransferase and aspartate aminotransferase levels.

He subsequently was evaluated at our hospital. He had no notable medical history and was afebrile. Physical examination revealed multiple erythematous nodules, abscesses, and ulcers on the left arm. There were several nodules with open sinus tracts and seropurulent crusts along with numerous atrophic, ovoid, stellate scars. Other nodules and ulcers with purulent drainage were located along the lymphatic nodes extending up the patient’s left forearm (Figure 1A). The yellowish-white pus discharge from several active sinuses contained no apparent granules. The lesions were densely distributed along the elbow, wrist, and shoulder, which resulted in associated skin swelling and restricted joint movement. The left axillary lymph nodes were enlarged.

Laboratory analyses revealed a hemoglobin level of 9.6 g/dL (reference range, 13–17.5 g/dL), platelet count of 621×10⁹/L (reference range, 125–350×10⁹/L), and leukocyte count of 14.3×10⁹/L (reference range, 3.5–9.5 ×10⁹/L). C-reactive protein level was 88.4 mg/L (reference range, 0–10 mg/L). Blood, renal, and liver tests, as well as tumor marker, peripheral blood lymphocyte subset, immunoglobulin, and complement results were within reference ranges. Results for Treponema pallidum and HIV antibody tests were negative. Hepatitis B virus markers were positive for hepatitis B surface antigen, hepatitis B e antigen, and hepatitis B core antibody, and the serum concentration of hepatitis B virus DNA was 3.12×10⁷ IU/mL (reference range, <5×10² IU/mL). Computed tomography of the chest and cranium were unremarkable. Ultrasonography of the left arm revealed multiple vertical sinus tracts and several horizontal communicating branches that were accompanied by worm-eaten bone destruction (Figure 2).

Additional testing included histopathologic staining of a skin tissue specimen—hematoxylin and eosin, periodic acid–Schiff, and acid-fast staining—showed nonspecific, diffuse, inflammatory cell infiltration suggestive of chronic suppurative granuloma (Figure 3) but failed to reveal any special strains or organisms. Gram stain examination of the purulent fluid collected from the subcutaneous tissue showed no apparent positive bacillus or filamentous granules. The specimen was then inoculated on Sabouraud dextrose agar and Lowenstein-Jensen medium for fungus and mycobacteria culture, respectively. After 5 days, chalky, yellow, adherent colonies were observed on the Löwenstein-Jensen medium, and after 26 days, yellow crinkled colonies were observed on Sabouraud dextrose agar. The colonies were then inoculated on Columbia blood agar and incubated for 1 week to aid in the identification of organisms. Growth of yellow colonies that were adherent to the agar, moist, and smooth with a velvety surface, as well as a characteristic moldy odor resulted. Gram staining revealed gram-positive, thin, and beaded branching filaments (Figure 4). Based on colony characteristics, physiological properties, and biochemical tests, the isolate was identified as Nocardia. Results of further investigations employing polymerase chain reaction analysis of the skin specimen and bacterial colonies using a Nocardia genus 596-bp fragment of 16S ribosomal RNA primer (forward primer NG1: 5’-ACCGACCACAAGGGG-3’, reverse primer NG2: 5’-GGTTGTAACCTCTTCGA-3’)⁶ were completely consistent with the reference for identification of N brasiliensis. Evaluation of these results led to a diagnosis of cutaneous nocardiosis after traumatic inoculation.

Because there was a high suspicion of actinophytosis or nocardiosis at admission, the patient received a combination antibiotic treatment with intravenous aqueous penicillin (4 million U every 4 hours) and oral trimethoprim-sulfamethoxazole (160/800 mg twice daily). Subsequently, treatment was changed to a combination of oral trimethoprim-sulfamethoxazole (160/800 mg twice daily) and moxifloxacin (400 mg once daily) based on pathogen identification and antibiotic sensitivity testing. After 1 month of treatment, the cutaneous lesions and left limb swelling dramatically improved and purulent drainage ceased, though some scarring occurred during the healing process. In addition, the mobility of the affected shoulder, elbow, and wrist joints slightly improved. Notable improvement in the mobility and swelling of the joints was observed at 6-month follow-up (Figure 1B). The patient continues to be monitored on an outpatient basis.

Cutaneous nocardiosis is a disfiguring granulomatous infection involving cutaneous and subcutaneous tissue that can progress to cause injury to viscera and bone.⁷ It has been called one of the great imitators because cutaneous nocardiosis can present in multiple forms,^8,9 including mycetoma, sporotrichoid infection, superficial skin infection, and disseminated infection with cutaneous involvement. The differential diagnoses of cutaneous nocardiosis are broad and include tuberculosis; actinomycosis; deep fungal infections such as sporotrichosis, blastomycosis, phaeohyphomycosis, histoplasmosis, and coccidioidomycosis; other bacterial causes of cellulitis, abscess, or ecthyma; and malignancies.¹⁰ The principle method of diagnosis is the identification of Nocardia from the infection site.

Our patient ultimately was diagnosed with primary cutaneous nocardiosis resulting from a traumatic injury to the skin that was contaminated with soil. The clinical manifestation pattern was a compound type, including both mycetoma and sporotrichoid infections. Initially, Nocardia mycetoma occurred with subcutaneous infection by direct extension^10,11 and appeared as dense, predominantly painless, swollen lesions. After 4 years, the skin lesions continued to spread linearly to the patient’s upper arm and forearm and manifested as the sporotrichoid infection type with painful swollen lesions at the site of inoculation and painful enlargement of the ipsilateral axillary lymph node.

Although nocardiosis is found worldwide, it is endemic to tropical and subtropical regions such as India, Africa, Southeast Asia, and Latin America.¹² Nocardiosis most often is observed in individuals aged 20 to 40 years. It affects men more than women, and it commonly occurs in field laborers and cultivators whose occupations involve direct contact with the soil.¹³ Most lesions are found on the lower extremities, though localized nocardiosis infections can occur in other areas such as the neck, breasts, back, buttocks, and elbows.

Our patient initially was misdiagnosed, and treatment was delayed for several reasons. First, nocardiosis is not common in China, and most clinicians are unfamiliar with the disease. Second, the related lesions do not have specific features, and our patient had a complex clinical presentation that included mycetoma and sporotrichoid infection. Third, the characteristic grain of Nocardia species is small but that of N brasiliensis is even smaller (approximately 0.1–0.2 mm in diameter), which makes visualization difficult in both histopathologic and microbiologic examinations.¹⁴ The histopathologic examination results of our patient in the local hospital were nonspecific. Fourth, our patient did not initially go to the hospital but instead purchased some over-the-counter antibiotic ointments for external application because the lesions were painless. Moreover, microbiologic smear and culture examinations were not conducted in the local hospital before administering antituberculosis treatment to the patient. Instead, a polymerase chain reaction examination of skin lesion tissue for tubercle bacilli and atypical mycobacteria was negative. These findings imply that the traditional microbial smear and culture evaluations cannot be omitted. Furthermore, culture examinations should be conducted on multiple skin tissue and purulent fluid specimens to increase the likelihood of detection. These cultures should be monitored for at least 2 to 4 weeks because Nocardia is a slow-growing organism.¹⁰

The optimal antimicrobial treatment regimens for nocardiosis have not been firmly established.¹⁵ Trimethoprim-sulfamethoxazole is regarded as the first-line antimicrobial agent for treatment of nocardial infections. The optimal duration of antimicrobial therapy for nocardiosis also has not been determined, and the treatment regimen depends on the severity and extent of the infection as well as on the presence of infection-related complications. The main complication is bone involvement. Notable bony changes include periosteal thickening, osteoporosis, and osteolysis.

We considered the severity of skin lesions and bone marrow invasion in our patient and planned to treat him continually with oral trimethoprim-sulfamethoxazole according to the in vitro drug susceptibility test. The patient showed clinical improvement after 1 month of treatment, and he continued to improve after 6 months of treatment. To prevent recurrence, we found it necessary to treat the patient with a long-term antibiotic course over 6 to 12 months.¹⁶

Cutaneous nocardiosis remains a diagnostic challenge because of its nonspecific and diverse clinical and histopathological presentations. Diagnosis is further complicated by the inherent difficulty of cultivating and identifying the clinical isolate in the laboratory. A high degree of clinical suspicion followed by successful identification of the organism by a laboratory technologist will aid in the early diagnosis and treatment of the infection, ultimately reducing the risk for complications and morbidity.

To the Editor:

The organisms of the genus Nocardia are gram-positive, ubiquitous, aerobic actinomycetes found worldwide in soil, decaying organic material, and water.¹ The genus Nocardia includes more than 50 species; some species, such as Nocardia asteroides, Nocardia farcinica, Nocardia nova, and Nocardia brasiliensis, are the cause of nocardiosis in humans and animals.^2,3 Nocardiosis is a rare and opportunistic infection that predominantly affects immunocompromised individuals; however, up to 30% of infections can occur in immunocompetent hosts.⁴ Nocardiosis can manifest in 3 disease forms: cutaneous, pulmonary, or disseminated. Cutaneous nocardiosis commonly develops in immunocompetent individuals who have experienced a predisposing traumatic injury to the skin,⁵ and it can exhibit a diverse variety of clinical manifestations, making diagnosis difficult. We describe a case of serious progressive primary cutaneous nocardiosis with an unusual presentation in an immunocompetent patient.

A 26-year-old immunocompetent man presented with pain, swelling, nodules, abscesses, ulcers, and sinus drainage of the left arm. The left elbow lesion initially developed at the site of a trauma 6 years prior that was painless but was contaminated with mossy soil. The condition slowly progressed over the next 2 years, and the patient experienced increased swelling and eventually developed multiple draining sinus tracts. Over the next 4 years, the lesions multiplied, spreading to the forearm and upper arm; associated severe pain and swelling at the elbow and wrist joint developed. The patient sought medical care at a local hospital and subsequently was diagnosed with suspected cutaneous tuberculosis. The patient was empirically treated with a 6-month course of isoniazid, rifampicin, pyrazinamide, and ethambutol; however, the lesions continued to progress and worsen. The patient had to stop antibiotic treatment because of substantially elevated alanine aminotransferase and aspartate aminotransferase levels.

He subsequently was evaluated at our hospital. He had no notable medical history and was afebrile. Physical examination revealed multiple erythematous nodules, abscesses, and ulcers on the left arm. There were several nodules with open sinus tracts and seropurulent crusts along with numerous atrophic, ovoid, stellate scars. Other nodules and ulcers with purulent drainage were located along the lymphatic nodes extending up the patient’s left forearm (Figure 1A). The yellowish-white pus discharge from several active sinuses contained no apparent granules. The lesions were densely distributed along the elbow, wrist, and shoulder, which resulted in associated skin swelling and restricted joint movement. The left axillary lymph nodes were enlarged.

Laboratory analyses revealed a hemoglobin level of 9.6 g/dL (reference range, 13–17.5 g/dL), platelet count of 621×10⁹/L (reference range, 125–350×10⁹/L), and leukocyte count of 14.3×10⁹/L (reference range, 3.5–9.5 ×10⁹/L). C-reactive protein level was 88.4 mg/L (reference range, 0–10 mg/L). Blood, renal, and liver tests, as well as tumor marker, peripheral blood lymphocyte subset, immunoglobulin, and complement results were within reference ranges. Results for Treponema pallidum and HIV antibody tests were negative. Hepatitis B virus markers were positive for hepatitis B surface antigen, hepatitis B e antigen, and hepatitis B core antibody, and the serum concentration of hepatitis B virus DNA was 3.12×10⁷ IU/mL (reference range, <5×10² IU/mL). Computed tomography of the chest and cranium were unremarkable. Ultrasonography of the left arm revealed multiple vertical sinus tracts and several horizontal communicating branches that were accompanied by worm-eaten bone destruction (Figure 2).

Additional testing included histopathologic staining of a skin tissue specimen—hematoxylin and eosin, periodic acid–Schiff, and acid-fast staining—showed nonspecific, diffuse, inflammatory cell infiltration suggestive of chronic suppurative granuloma (Figure 3) but failed to reveal any special strains or organisms. Gram stain examination of the purulent fluid collected from the subcutaneous tissue showed no apparent positive bacillus or filamentous granules. The specimen was then inoculated on Sabouraud dextrose agar and Lowenstein-Jensen medium for fungus and mycobacteria culture, respectively. After 5 days, chalky, yellow, adherent colonies were observed on the Löwenstein-Jensen medium, and after 26 days, yellow crinkled colonies were observed on Sabouraud dextrose agar. The colonies were then inoculated on Columbia blood agar and incubated for 1 week to aid in the identification of organisms. Growth of yellow colonies that were adherent to the agar, moist, and smooth with a velvety surface, as well as a characteristic moldy odor resulted. Gram staining revealed gram-positive, thin, and beaded branching filaments (Figure 4). Based on colony characteristics, physiological properties, and biochemical tests, the isolate was identified as Nocardia. Results of further investigations employing polymerase chain reaction analysis of the skin specimen and bacterial colonies using a Nocardia genus 596-bp fragment of 16S ribosomal RNA primer (forward primer NG1: 5’-ACCGACCACAAGGGG-3’, reverse primer NG2: 5’-GGTTGTAACCTCTTCGA-3’)⁶ were completely consistent with the reference for identification of N brasiliensis. Evaluation of these results led to a diagnosis of cutaneous nocardiosis after traumatic inoculation.

Because there was a high suspicion of actinophytosis or nocardiosis at admission, the patient received a combination antibiotic treatment with intravenous aqueous penicillin (4 million U every 4 hours) and oral trimethoprim-sulfamethoxazole (160/800 mg twice daily). Subsequently, treatment was changed to a combination of oral trimethoprim-sulfamethoxazole (160/800 mg twice daily) and moxifloxacin (400 mg once daily) based on pathogen identification and antibiotic sensitivity testing. After 1 month of treatment, the cutaneous lesions and left limb swelling dramatically improved and purulent drainage ceased, though some scarring occurred during the healing process. In addition, the mobility of the affected shoulder, elbow, and wrist joints slightly improved. Notable improvement in the mobility and swelling of the joints was observed at 6-month follow-up (Figure 1B). The patient continues to be monitored on an outpatient basis.

Cutaneous nocardiosis is a disfiguring granulomatous infection involving cutaneous and subcutaneous tissue that can progress to cause injury to viscera and bone.⁷ It has been called one of the great imitators because cutaneous nocardiosis can present in multiple forms,^8,9 including mycetoma, sporotrichoid infection, superficial skin infection, and disseminated infection with cutaneous involvement. The differential diagnoses of cutaneous nocardiosis are broad and include tuberculosis; actinomycosis; deep fungal infections such as sporotrichosis, blastomycosis, phaeohyphomycosis, histoplasmosis, and coccidioidomycosis; other bacterial causes of cellulitis, abscess, or ecthyma; and malignancies.¹⁰ The principle method of diagnosis is the identification of Nocardia from the infection site.

Our patient ultimately was diagnosed with primary cutaneous nocardiosis resulting from a traumatic injury to the skin that was contaminated with soil. The clinical manifestation pattern was a compound type, including both mycetoma and sporotrichoid infections. Initially, Nocardia mycetoma occurred with subcutaneous infection by direct extension^10,11 and appeared as dense, predominantly painless, swollen lesions. After 4 years, the skin lesions continued to spread linearly to the patient’s upper arm and forearm and manifested as the sporotrichoid infection type with painful swollen lesions at the site of inoculation and painful enlargement of the ipsilateral axillary lymph node.

Although nocardiosis is found worldwide, it is endemic to tropical and subtropical regions such as India, Africa, Southeast Asia, and Latin America.¹² Nocardiosis most often is observed in individuals aged 20 to 40 years. It affects men more than women, and it commonly occurs in field laborers and cultivators whose occupations involve direct contact with the soil.¹³ Most lesions are found on the lower extremities, though localized nocardiosis infections can occur in other areas such as the neck, breasts, back, buttocks, and elbows.

Our patient initially was misdiagnosed, and treatment was delayed for several reasons. First, nocardiosis is not common in China, and most clinicians are unfamiliar with the disease. Second, the related lesions do not have specific features, and our patient had a complex clinical presentation that included mycetoma and sporotrichoid infection. Third, the characteristic grain of Nocardia species is small but that of N brasiliensis is even smaller (approximately 0.1–0.2 mm in diameter), which makes visualization difficult in both histopathologic and microbiologic examinations.¹⁴ The histopathologic examination results of our patient in the local hospital were nonspecific. Fourth, our patient did not initially go to the hospital but instead purchased some over-the-counter antibiotic ointments for external application because the lesions were painless. Moreover, microbiologic smear and culture examinations were not conducted in the local hospital before administering antituberculosis treatment to the patient. Instead, a polymerase chain reaction examination of skin lesion tissue for tubercle bacilli and atypical mycobacteria was negative. These findings imply that the traditional microbial smear and culture evaluations cannot be omitted. Furthermore, culture examinations should be conducted on multiple skin tissue and purulent fluid specimens to increase the likelihood of detection. These cultures should be monitored for at least 2 to 4 weeks because Nocardia is a slow-growing organism.¹⁰

The optimal antimicrobial treatment regimens for nocardiosis have not been firmly established.¹⁵ Trimethoprim-sulfamethoxazole is regarded as the first-line antimicrobial agent for treatment of nocardial infections. The optimal duration of antimicrobial therapy for nocardiosis also has not been determined, and the treatment regimen depends on the severity and extent of the infection as well as on the presence of infection-related complications. The main complication is bone involvement. Notable bony changes include periosteal thickening, osteoporosis, and osteolysis.

We considered the severity of skin lesions and bone marrow invasion in our patient and planned to treat him continually with oral trimethoprim-sulfamethoxazole according to the in vitro drug susceptibility test. The patient showed clinical improvement after 1 month of treatment, and he continued to improve after 6 months of treatment. To prevent recurrence, we found it necessary to treat the patient with a long-term antibiotic course over 6 to 12 months.¹⁶

Cutaneous nocardiosis remains a diagnostic challenge because of its nonspecific and diverse clinical and histopathological presentations. Diagnosis is further complicated by the inherent difficulty of cultivating and identifying the clinical isolate in the laboratory. A high degree of clinical suspicion followed by successful identification of the organism by a laboratory technologist will aid in the early diagnosis and treatment of the infection, ultimately reducing the risk for complications and morbidity.

To the Editor:

The organisms of the genus Nocardia are gram-positive, ubiquitous, aerobic actinomycetes found worldwide in soil, decaying organic material, and water.¹ The genus Nocardia includes more than 50 species; some species, such as Nocardia asteroides, Nocardia farcinica, Nocardia nova, and Nocardia brasiliensis, are the cause of nocardiosis in humans and animals.^2,3 Nocardiosis is a rare and opportunistic infection that predominantly affects immunocompromised individuals; however, up to 30% of infections can occur in immunocompetent hosts.⁴ Nocardiosis can manifest in 3 disease forms: cutaneous, pulmonary, or disseminated. Cutaneous nocardiosis commonly develops in immunocompetent individuals who have experienced a predisposing traumatic injury to the skin,⁵ and it can exhibit a diverse variety of clinical manifestations, making diagnosis difficult. We describe a case of serious progressive primary cutaneous nocardiosis with an unusual presentation in an immunocompetent patient.

A 26-year-old immunocompetent man presented with pain, swelling, nodules, abscesses, ulcers, and sinus drainage of the left arm. The left elbow lesion initially developed at the site of a trauma 6 years prior that was painless but was contaminated with mossy soil. The condition slowly progressed over the next 2 years, and the patient experienced increased swelling and eventually developed multiple draining sinus tracts. Over the next 4 years, the lesions multiplied, spreading to the forearm and upper arm; associated severe pain and swelling at the elbow and wrist joint developed. The patient sought medical care at a local hospital and subsequently was diagnosed with suspected cutaneous tuberculosis. The patient was empirically treated with a 6-month course of isoniazid, rifampicin, pyrazinamide, and ethambutol; however, the lesions continued to progress and worsen. The patient had to stop antibiotic treatment because of substantially elevated alanine aminotransferase and aspartate aminotransferase levels.

He subsequently was evaluated at our hospital. He had no notable medical history and was afebrile. Physical examination revealed multiple erythematous nodules, abscesses, and ulcers on the left arm. There were several nodules with open sinus tracts and seropurulent crusts along with numerous atrophic, ovoid, stellate scars. Other nodules and ulcers with purulent drainage were located along the lymphatic nodes extending up the patient’s left forearm (Figure 1A). The yellowish-white pus discharge from several active sinuses contained no apparent granules. The lesions were densely distributed along the elbow, wrist, and shoulder, which resulted in associated skin swelling and restricted joint movement. The left axillary lymph nodes were enlarged.

Laboratory analyses revealed a hemoglobin level of 9.6 g/dL (reference range, 13–17.5 g/dL), platelet count of 621×10⁹/L (reference range, 125–350×10⁹/L), and leukocyte count of 14.3×10⁹/L (reference range, 3.5–9.5 ×10⁹/L). C-reactive protein level was 88.4 mg/L (reference range, 0–10 mg/L). Blood, renal, and liver tests, as well as tumor marker, peripheral blood lymphocyte subset, immunoglobulin, and complement results were within reference ranges. Results for Treponema pallidum and HIV antibody tests were negative. Hepatitis B virus markers were positive for hepatitis B surface antigen, hepatitis B e antigen, and hepatitis B core antibody, and the serum concentration of hepatitis B virus DNA was 3.12×10⁷ IU/mL (reference range, <5×10² IU/mL). Computed tomography of the chest and cranium were unremarkable. Ultrasonography of the left arm revealed multiple vertical sinus tracts and several horizontal communicating branches that were accompanied by worm-eaten bone destruction (Figure 2).

Additional testing included histopathologic staining of a skin tissue specimen—hematoxylin and eosin, periodic acid–Schiff, and acid-fast staining—showed nonspecific, diffuse, inflammatory cell infiltration suggestive of chronic suppurative granuloma (Figure 3) but failed to reveal any special strains or organisms. Gram stain examination of the purulent fluid collected from the subcutaneous tissue showed no apparent positive bacillus or filamentous granules. The specimen was then inoculated on Sabouraud dextrose agar and Lowenstein-Jensen medium for fungus and mycobacteria culture, respectively. After 5 days, chalky, yellow, adherent colonies were observed on the Löwenstein-Jensen medium, and after 26 days, yellow crinkled colonies were observed on Sabouraud dextrose agar. The colonies were then inoculated on Columbia blood agar and incubated for 1 week to aid in the identification of organisms. Growth of yellow colonies that were adherent to the agar, moist, and smooth with a velvety surface, as well as a characteristic moldy odor resulted. Gram staining revealed gram-positive, thin, and beaded branching filaments (Figure 4). Based on colony characteristics, physiological properties, and biochemical tests, the isolate was identified as Nocardia. Results of further investigations employing polymerase chain reaction analysis of the skin specimen and bacterial colonies using a Nocardia genus 596-bp fragment of 16S ribosomal RNA primer (forward primer NG1: 5’-ACCGACCACAAGGGG-3’, reverse primer NG2: 5’-GGTTGTAACCTCTTCGA-3’)⁶ were completely consistent with the reference for identification of N brasiliensis. Evaluation of these results led to a diagnosis of cutaneous nocardiosis after traumatic inoculation.

Because there was a high suspicion of actinophytosis or nocardiosis at admission, the patient received a combination antibiotic treatment with intravenous aqueous penicillin (4 million U every 4 hours) and oral trimethoprim-sulfamethoxazole (160/800 mg twice daily). Subsequently, treatment was changed to a combination of oral trimethoprim-sulfamethoxazole (160/800 mg twice daily) and moxifloxacin (400 mg once daily) based on pathogen identification and antibiotic sensitivity testing. After 1 month of treatment, the cutaneous lesions and left limb swelling dramatically improved and purulent drainage ceased, though some scarring occurred during the healing process. In addition, the mobility of the affected shoulder, elbow, and wrist joints slightly improved. Notable improvement in the mobility and swelling of the joints was observed at 6-month follow-up (Figure 1B). The patient continues to be monitored on an outpatient basis.

Cutaneous nocardiosis is a disfiguring granulomatous infection involving cutaneous and subcutaneous tissue that can progress to cause injury to viscera and bone.⁷ It has been called one of the great imitators because cutaneous nocardiosis can present in multiple forms,^8,9 including mycetoma, sporotrichoid infection, superficial skin infection, and disseminated infection with cutaneous involvement. The differential diagnoses of cutaneous nocardiosis are broad and include tuberculosis; actinomycosis; deep fungal infections such as sporotrichosis, blastomycosis, phaeohyphomycosis, histoplasmosis, and coccidioidomycosis; other bacterial causes of cellulitis, abscess, or ecthyma; and malignancies.¹⁰ The principle method of diagnosis is the identification of Nocardia from the infection site.

Our patient ultimately was diagnosed with primary cutaneous nocardiosis resulting from a traumatic injury to the skin that was contaminated with soil. The clinical manifestation pattern was a compound type, including both mycetoma and sporotrichoid infections. Initially, Nocardia mycetoma occurred with subcutaneous infection by direct extension^10,11 and appeared as dense, predominantly painless, swollen lesions. After 4 years, the skin lesions continued to spread linearly to the patient’s upper arm and forearm and manifested as the sporotrichoid infection type with painful swollen lesions at the site of inoculation and painful enlargement of the ipsilateral axillary lymph node.

Although nocardiosis is found worldwide, it is endemic to tropical and subtropical regions such as India, Africa, Southeast Asia, and Latin America.¹² Nocardiosis most often is observed in individuals aged 20 to 40 years. It affects men more than women, and it commonly occurs in field laborers and cultivators whose occupations involve direct contact with the soil.¹³ Most lesions are found on the lower extremities, though localized nocardiosis infections can occur in other areas such as the neck, breasts, back, buttocks, and elbows.

Our patient initially was misdiagnosed, and treatment was delayed for several reasons. First, nocardiosis is not common in China, and most clinicians are unfamiliar with the disease. Second, the related lesions do not have specific features, and our patient had a complex clinical presentation that included mycetoma and sporotrichoid infection. Third, the characteristic grain of Nocardia species is small but that of N brasiliensis is even smaller (approximately 0.1–0.2 mm in diameter), which makes visualization difficult in both histopathologic and microbiologic examinations.¹⁴ The histopathologic examination results of our patient in the local hospital were nonspecific. Fourth, our patient did not initially go to the hospital but instead purchased some over-the-counter antibiotic ointments for external application because the lesions were painless. Moreover, microbiologic smear and culture examinations were not conducted in the local hospital before administering antituberculosis treatment to the patient. Instead, a polymerase chain reaction examination of skin lesion tissue for tubercle bacilli and atypical mycobacteria was negative. These findings imply that the traditional microbial smear and culture evaluations cannot be omitted. Furthermore, culture examinations should be conducted on multiple skin tissue and purulent fluid specimens to increase the likelihood of detection. These cultures should be monitored for at least 2 to 4 weeks because Nocardia is a slow-growing organism.¹⁰

The optimal antimicrobial treatment regimens for nocardiosis have not been firmly established.¹⁵ Trimethoprim-sulfamethoxazole is regarded as the first-line antimicrobial agent for treatment of nocardial infections. The optimal duration of antimicrobial therapy for nocardiosis also has not been determined, and the treatment regimen depends on the severity and extent of the infection as well as on the presence of infection-related complications. The main complication is bone involvement. Notable bony changes include periosteal thickening, osteoporosis, and osteolysis.

We considered the severity of skin lesions and bone marrow invasion in our patient and planned to treat him continually with oral trimethoprim-sulfamethoxazole according to the in vitro drug susceptibility test. The patient showed clinical improvement after 1 month of treatment, and he continued to improve after 6 months of treatment. To prevent recurrence, we found it necessary to treat the patient with a long-term antibiotic course over 6 to 12 months.¹⁶

Cutaneous nocardiosis remains a diagnostic challenge because of its nonspecific and diverse clinical and histopathological presentations. Diagnosis is further complicated by the inherent difficulty of cultivating and identifying the clinical isolate in the laboratory. A high degree of clinical suspicion followed by successful identification of the organism by a laboratory technologist will aid in the early diagnosis and treatment of the infection, ultimately reducing the risk for complications and morbidity.

Vaginal swabs are more effective than urine analysis in detecting certain types of sexually transmitted infections, researchers have found.

In the study, which was published online in the Annals of Family Medicine, investigators found that the diagnostic sensitivity of commercially available vaginal swabs was significantly greater than that of urine tests in detecting certain infections, including those caused by Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.

Researchers studied chlamydia and gonorrhea, which are two of the most frequently reported STIs in the United States. Trichomoniasis is the most curable nonviral STI globally, with 156 million cases worldwide in 2016.

The Centers for Disease Control and Prevention has long recommended that vaginal swabs be used to produce optimal samples.

But despite the CDC’s recommendation, urine analysis for these STIs is more commonly used than vaginal swabs among U.S. health care providers.

“We’re using a poor sample type, and we can do better,” said Barbara Van Der Pol, PhD, a professor of medicine and public health at the University of Alabama at Birmingham and an author of the new study, a meta-analysis of 97 studies published between 1995 and 2021.

Vaginal swabs for chlamydia trachomatis had a diagnostic sensitivity of 94.1% (95% confidence interval, 93.2%-94.9%; P < .001), higher than urine testing (86.9%; 95% CI, 85.6%-88.0%; P < .001). The pooled sensitivity estimates for Neisseria gonorrhoeae were 96.5% (95% CI, 94.8%-97.7%; P < .001) for vaginal swabs and 90.7% (95% CI, 88.4%-92.5%; P < .001) for urine specimens.

The difference in pooled sensitivity estimates between vaginal swabs and urine analyses for Trichomonas vaginalis was 98% (95% CI, 97.0%-98.7%; P < .001) for vaginal swabs and 95.1% (95% CI, 93.6%-96.3%) for urine specimens.

STIs included in the study are not typically found in the urethra and appear in urine analyses only if cervical or vaginal cells have dripped into a urine sample. Dr. Van Der Pol and her colleagues estimated that the use of urine samples rather than vaginal swabs may result in more than 400,000 undiagnosed infections annually.

Undiagnosed and untreated STIs can lead to transmissions of the infection as well as infertility and can have negative effects on romantic relationships, according to Dr. Van Der Pol.

Sarah Wood, MD, an attending physician at Children’s Hospital of Philadelphia, said some health care providers may use urine analysis because patients may be more comfortable with this method. The approach also can be more convenient for medical offices: All they must do is hand a specimen container to the patient.

Conversations between clinicians and patients about vaginal swabbing may be considered “sensitive” and the swabbing more invasive, Dr. Wood, an author of an editorial accompanying the journal article, said. Clinicians may also lack awareness that the swab is a more sensitive method of detecting these STIs.

“We all want to do what’s right for our patient, but we often don’t know what’s right for the patient,” Dr. Wood said. “I don’t think people are really aware of a potential real difference in outcomes with one method over the other.”

Dr. Wood advised making STI screening using vaginal swabs more common by “offering universal opt-out screening, so not waiting until you find out if someone’s having sex but just sort of saying, ‘Hey, across our practice, we screen everybody for chlamydia. Is that something that you want to do today?’ That approach sort of takes out the piece of talking about sex, talking about sexual activity.”

Dr. Van Der Pol, who said she has worked in STI diagnostics for 40 years, said she was not surprised by the results and hopes the study changes how samples are collected and used.

“I really hope that it influences practice so that we really start using vaginal swabs, because it gives us better diagnostics for chlamydia and gonorrhea,” Dr. Van Der Pol said.

“Also, then starting to think about comprehensive women’s care in such a way that they actually order other tests on that same sample if a woman is presenting with complaints.”

A version of this article originally appeared on Medscape.com.

Vaginal swabs are more effective than urine analysis in detecting certain types of sexually transmitted infections, researchers have found.

In the study, which was published online in the Annals of Family Medicine, investigators found that the diagnostic sensitivity of commercially available vaginal swabs was significantly greater than that of urine tests in detecting certain infections, including those caused by Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.

Researchers studied chlamydia and gonorrhea, which are two of the most frequently reported STIs in the United States. Trichomoniasis is the most curable nonviral STI globally, with 156 million cases worldwide in 2016.

The Centers for Disease Control and Prevention has long recommended that vaginal swabs be used to produce optimal samples.

But despite the CDC’s recommendation, urine analysis for these STIs is more commonly used than vaginal swabs among U.S. health care providers.

“We’re using a poor sample type, and we can do better,” said Barbara Van Der Pol, PhD, a professor of medicine and public health at the University of Alabama at Birmingham and an author of the new study, a meta-analysis of 97 studies published between 1995 and 2021.

Vaginal swabs for chlamydia trachomatis had a diagnostic sensitivity of 94.1% (95% confidence interval, 93.2%-94.9%; P < .001), higher than urine testing (86.9%; 95% CI, 85.6%-88.0%; P < .001). The pooled sensitivity estimates for Neisseria gonorrhoeae were 96.5% (95% CI, 94.8%-97.7%; P < .001) for vaginal swabs and 90.7% (95% CI, 88.4%-92.5%; P < .001) for urine specimens.

The difference in pooled sensitivity estimates between vaginal swabs and urine analyses for Trichomonas vaginalis was 98% (95% CI, 97.0%-98.7%; P < .001) for vaginal swabs and 95.1% (95% CI, 93.6%-96.3%) for urine specimens.

STIs included in the study are not typically found in the urethra and appear in urine analyses only if cervical or vaginal cells have dripped into a urine sample. Dr. Van Der Pol and her colleagues estimated that the use of urine samples rather than vaginal swabs may result in more than 400,000 undiagnosed infections annually.

Undiagnosed and untreated STIs can lead to transmissions of the infection as well as infertility and can have negative effects on romantic relationships, according to Dr. Van Der Pol.

Sarah Wood, MD, an attending physician at Children’s Hospital of Philadelphia, said some health care providers may use urine analysis because patients may be more comfortable with this method. The approach also can be more convenient for medical offices: All they must do is hand a specimen container to the patient.

Conversations between clinicians and patients about vaginal swabbing may be considered “sensitive” and the swabbing more invasive, Dr. Wood, an author of an editorial accompanying the journal article, said. Clinicians may also lack awareness that the swab is a more sensitive method of detecting these STIs.

“We all want to do what’s right for our patient, but we often don’t know what’s right for the patient,” Dr. Wood said. “I don’t think people are really aware of a potential real difference in outcomes with one method over the other.”

Dr. Wood advised making STI screening using vaginal swabs more common by “offering universal opt-out screening, so not waiting until you find out if someone’s having sex but just sort of saying, ‘Hey, across our practice, we screen everybody for chlamydia. Is that something that you want to do today?’ That approach sort of takes out the piece of talking about sex, talking about sexual activity.”

Dr. Van Der Pol, who said she has worked in STI diagnostics for 40 years, said she was not surprised by the results and hopes the study changes how samples are collected and used.

“I really hope that it influences practice so that we really start using vaginal swabs, because it gives us better diagnostics for chlamydia and gonorrhea,” Dr. Van Der Pol said.

“Also, then starting to think about comprehensive women’s care in such a way that they actually order other tests on that same sample if a woman is presenting with complaints.”

A version of this article originally appeared on Medscape.com.

Vaginal swabs are more effective than urine analysis in detecting certain types of sexually transmitted infections, researchers have found.

In the study, which was published online in the Annals of Family Medicine, investigators found that the diagnostic sensitivity of commercially available vaginal swabs was significantly greater than that of urine tests in detecting certain infections, including those caused by Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.

Researchers studied chlamydia and gonorrhea, which are two of the most frequently reported STIs in the United States. Trichomoniasis is the most curable nonviral STI globally, with 156 million cases worldwide in 2016.

The Centers for Disease Control and Prevention has long recommended that vaginal swabs be used to produce optimal samples.

But despite the CDC’s recommendation, urine analysis for these STIs is more commonly used than vaginal swabs among U.S. health care providers.

“We’re using a poor sample type, and we can do better,” said Barbara Van Der Pol, PhD, a professor of medicine and public health at the University of Alabama at Birmingham and an author of the new study, a meta-analysis of 97 studies published between 1995 and 2021.

Vaginal swabs for chlamydia trachomatis had a diagnostic sensitivity of 94.1% (95% confidence interval, 93.2%-94.9%; P < .001), higher than urine testing (86.9%; 95% CI, 85.6%-88.0%; P < .001). The pooled sensitivity estimates for Neisseria gonorrhoeae were 96.5% (95% CI, 94.8%-97.7%; P < .001) for vaginal swabs and 90.7% (95% CI, 88.4%-92.5%; P < .001) for urine specimens.

The difference in pooled sensitivity estimates between vaginal swabs and urine analyses for Trichomonas vaginalis was 98% (95% CI, 97.0%-98.7%; P < .001) for vaginal swabs and 95.1% (95% CI, 93.6%-96.3%) for urine specimens.

STIs included in the study are not typically found in the urethra and appear in urine analyses only if cervical or vaginal cells have dripped into a urine sample. Dr. Van Der Pol and her colleagues estimated that the use of urine samples rather than vaginal swabs may result in more than 400,000 undiagnosed infections annually.

Undiagnosed and untreated STIs can lead to transmissions of the infection as well as infertility and can have negative effects on romantic relationships, according to Dr. Van Der Pol.

Sarah Wood, MD, an attending physician at Children’s Hospital of Philadelphia, said some health care providers may use urine analysis because patients may be more comfortable with this method. The approach also can be more convenient for medical offices: All they must do is hand a specimen container to the patient.

Conversations between clinicians and patients about vaginal swabbing may be considered “sensitive” and the swabbing more invasive, Dr. Wood, an author of an editorial accompanying the journal article, said. Clinicians may also lack awareness that the swab is a more sensitive method of detecting these STIs.

“We all want to do what’s right for our patient, but we often don’t know what’s right for the patient,” Dr. Wood said. “I don’t think people are really aware of a potential real difference in outcomes with one method over the other.”

Dr. Wood advised making STI screening using vaginal swabs more common by “offering universal opt-out screening, so not waiting until you find out if someone’s having sex but just sort of saying, ‘Hey, across our practice, we screen everybody for chlamydia. Is that something that you want to do today?’ That approach sort of takes out the piece of talking about sex, talking about sexual activity.”

Dr. Van Der Pol, who said she has worked in STI diagnostics for 40 years, said she was not surprised by the results and hopes the study changes how samples are collected and used.

“I really hope that it influences practice so that we really start using vaginal swabs, because it gives us better diagnostics for chlamydia and gonorrhea,” Dr. Van Der Pol said.

“Also, then starting to think about comprehensive women’s care in such a way that they actually order other tests on that same sample if a woman is presenting with complaints.”

A version of this article originally appeared on Medscape.com.

An electronic nose effectively detected Staphylococcus aureus in children with cystic fibrosis, based on data from 100 individuals.

Staphylococcus aureus is the most common pathogen found in children with cystic fibrosis (CF), but current detection strategies are based on microbiology cultures, wrote Johann-Christoph Licht, a medical student at the University of Toronto, and colleagues.

Noninvasive tools are needed to screen children with CF early for respiratory infections, the researchers said.

The electronic Nose (eNose) is a technology that detects volatile organic compounds (VOCs). Although exhaled breath can be used to create distinct profiles, the ability of eNose to identify S. aureus (SA) in the breath of children with CF remains unclear, they wrote.

In a study published in the Journal of Cystic Fibrosis, the researchers analyzed breath profiles data from 100 children with CF. The study population included children aged 5-18 years with clinically stable CF who were recruited from CF clinics during routine visits. Patients with a CF pulmonary exacerbation were excluded.

The children’s median predicted FEV₁ was 91%. The researchers collected sputum from 67 patients and throat cultures for 33 patients. A group of 25 age-matched healthy controls served for comparison.

Eighty patients were positive for CF pathogens. Of these, 67 were positive for SA (44 with SA only and 23 with SA and at least one other pathogen).

Overall, patients with any CF pathogen on airway cultures were identified compared to airway cultures with no CF pathogens with an area under the curve accuracy of 79.0%.

Previous studies have shown a high rate of accuracy using eNose to detect Pseudomonas aeruginosa (PA). In the current study, the area under the curve accuracy for PA infection compared to no CF pathogens was 78%. Both SA-specific and PA-specific signatures were driven by different sensors in the eNose, which suggests pathogen-specific breath signatures, the researchers wrote.

The study findings were limited by several factors including the small number of patients with positive airway cultures for PA and the lack of data on variability of measures over time or treatment-induced changes, the researchers noted.

However, the results confirm the value of the eNose in real-time point-of-care detection of airway infection in children with CF, and this is the first study known to suggest the potential of an eNose to detect SA infection in particular in a routine clinical setting, the researchers wrote in their discussion.

Other points in favor of eNose compared to current practice include “low cost, ease of use and portability to the point-of-care,” they said. The eNose provides an opportunity for early detection of pathogens that challenges conventional microbiology testing, they concluded.

The study received no outside funding. Two coauthors disclosed fees and/or an interest in the company Breathomix BV.

An electronic nose effectively detected Staphylococcus aureus in children with cystic fibrosis, based on data from 100 individuals.

Staphylococcus aureus is the most common pathogen found in children with cystic fibrosis (CF), but current detection strategies are based on microbiology cultures, wrote Johann-Christoph Licht, a medical student at the University of Toronto, and colleagues.

Noninvasive tools are needed to screen children with CF early for respiratory infections, the researchers said.

The electronic Nose (eNose) is a technology that detects volatile organic compounds (VOCs). Although exhaled breath can be used to create distinct profiles, the ability of eNose to identify S. aureus (SA) in the breath of children with CF remains unclear, they wrote.

In a study published in the Journal of Cystic Fibrosis, the researchers analyzed breath profiles data from 100 children with CF. The study population included children aged 5-18 years with clinically stable CF who were recruited from CF clinics during routine visits. Patients with a CF pulmonary exacerbation were excluded.

The children’s median predicted FEV₁ was 91%. The researchers collected sputum from 67 patients and throat cultures for 33 patients. A group of 25 age-matched healthy controls served for comparison.

Eighty patients were positive for CF pathogens. Of these, 67 were positive for SA (44 with SA only and 23 with SA and at least one other pathogen).

Overall, patients with any CF pathogen on airway cultures were identified compared to airway cultures with no CF pathogens with an area under the curve accuracy of 79.0%.

Previous studies have shown a high rate of accuracy using eNose to detect Pseudomonas aeruginosa (PA). In the current study, the area under the curve accuracy for PA infection compared to no CF pathogens was 78%. Both SA-specific and PA-specific signatures were driven by different sensors in the eNose, which suggests pathogen-specific breath signatures, the researchers wrote.

The study findings were limited by several factors including the small number of patients with positive airway cultures for PA and the lack of data on variability of measures over time or treatment-induced changes, the researchers noted.

However, the results confirm the value of the eNose in real-time point-of-care detection of airway infection in children with CF, and this is the first study known to suggest the potential of an eNose to detect SA infection in particular in a routine clinical setting, the researchers wrote in their discussion.

Other points in favor of eNose compared to current practice include “low cost, ease of use and portability to the point-of-care,” they said. The eNose provides an opportunity for early detection of pathogens that challenges conventional microbiology testing, they concluded.

The study received no outside funding. Two coauthors disclosed fees and/or an interest in the company Breathomix BV.

An electronic nose effectively detected Staphylococcus aureus in children with cystic fibrosis, based on data from 100 individuals.

Staphylococcus aureus is the most common pathogen found in children with cystic fibrosis (CF), but current detection strategies are based on microbiology cultures, wrote Johann-Christoph Licht, a medical student at the University of Toronto, and colleagues.

Noninvasive tools are needed to screen children with CF early for respiratory infections, the researchers said.

The electronic Nose (eNose) is a technology that detects volatile organic compounds (VOCs). Although exhaled breath can be used to create distinct profiles, the ability of eNose to identify S. aureus (SA) in the breath of children with CF remains unclear, they wrote.

In a study published in the Journal of Cystic Fibrosis, the researchers analyzed breath profiles data from 100 children with CF. The study population included children aged 5-18 years with clinically stable CF who were recruited from CF clinics during routine visits. Patients with a CF pulmonary exacerbation were excluded.

The children’s median predicted FEV₁ was 91%. The researchers collected sputum from 67 patients and throat cultures for 33 patients. A group of 25 age-matched healthy controls served for comparison.

Eighty patients were positive for CF pathogens. Of these, 67 were positive for SA (44 with SA only and 23 with SA and at least one other pathogen).

Overall, patients with any CF pathogen on airway cultures were identified compared to airway cultures with no CF pathogens with an area under the curve accuracy of 79.0%.

Previous studies have shown a high rate of accuracy using eNose to detect Pseudomonas aeruginosa (PA). In the current study, the area under the curve accuracy for PA infection compared to no CF pathogens was 78%. Both SA-specific and PA-specific signatures were driven by different sensors in the eNose, which suggests pathogen-specific breath signatures, the researchers wrote.

The study findings were limited by several factors including the small number of patients with positive airway cultures for PA and the lack of data on variability of measures over time or treatment-induced changes, the researchers noted.

However, the results confirm the value of the eNose in real-time point-of-care detection of airway infection in children with CF, and this is the first study known to suggest the potential of an eNose to detect SA infection in particular in a routine clinical setting, the researchers wrote in their discussion.

Other points in favor of eNose compared to current practice include “low cost, ease of use and portability to the point-of-care,” they said. The eNose provides an opportunity for early detection of pathogens that challenges conventional microbiology testing, they concluded.

The study received no outside funding. Two coauthors disclosed fees and/or an interest in the company Breathomix BV.