Infectious Diseases

The Diagnosis: Erythema Nodosum Leprosum

Erythema nodosum leprosum (ENL) is a type 2 reaction sometimes seen in patients infected with Mycobacterium leprae—primarily those with lepromatous or borderline lepromatous subtypes. Clinically, ENL manifests with abrupt onset of tender erythematous papules with associated fevers and general malaise. Studies have demonstrated a complex immune system reaction in ENL, but the detailed pathophysiology is not fully understood.¹ Biopsies conducted within 24 hours of lesion formation are most elucidating. Foamy histiocytes admixed with neutrophils are seen in the subcutis, often causing a lobular panniculitis (quiz image).² Neutrophils rarely are seen in other types of leprosy and thus are a useful diagnostic clue for ENL. Vasculitis of small- to medium-sized vessels can be seen but is not a necessary diagnostic criterion. Fite staining will highlight many acid-fast bacilli within the histiocytes (Figure 1).

Erythema nodosum leprosum is treated with a combination of immunosuppressants such as prednisone and thalidomide. Our patient was taking triple-antibiotic therapy—dapsone, rifampin, and clofazimine—for lepromatous leprosy when the erythematous papules developed on the arms and legs. After a skin biopsy confirmed the diagnosis of ENL, he was started on prednisone 20 mg daily with plans for close follow-up. Unfortunately, the patient was subsequently lost to follow-up.

Acute febrile neutrophilic dermatosis (also known as Sweet syndrome) is an acute inflammatory disease characterized by abrupt onset of painful erythematous papules, plaques, or nodules on the skin. It often is seen in association with preceding infections (especially those in the upper respiratory or gastrointestinal tracts), hematologic malignancies, inflammatory bowel disease, or exposure to certain classes of medications (eg, granulocyte colony-stimulating factor, tyrosine kinase inhibitors, various antibiotics).³ Histologically, acute febrile neutrophilic dermatosis is characterized by dense neutrophilic infiltrates, often with notable dermal edema (Figure 2).⁴ Many cases also show leukocytoclastic vasculitis; however, foamy histiocytes are not a notable component of the inflammatory infiltrate, though a histiocytoid form of acute febrile neutrophilic dermatosis has been described.⁵ Infections must be rigorously ruled out prior to diagnosing a patient with acute febrile neutrophilic dermatosis, making it a diagnosis of exclusion.

Cutaneous coccidioidomycosis is an infection caused by the dimorphic fungi Coccidioides immitis or Coccidioides posadasii. Cutaneous disease is rare but can occur from direct inoculation or dissemination from pulmonary disease in immunocompetent or immunocompromised patients. Papules, pustules, or plaques are seen clinically. Histologically, cutaneous coccidioidomycosis shows spherules that vary from 10 to 100 μm and are filled with multiple smaller endospores (Figure 3).⁶ Pseudoepitheliomatous hyperplasia with dense suppurative and granulomatous infiltrates also is seen.

Erythema induratum is characterized by tender nodules on the lower extremities and has a substantial female predominance. Many cases are associated with Mycobacterium tuberculosis infection. The bacteria are not seen directly in the skin but are instead detectable through DNA polymerase chain reaction testing or investigation of other organ systems.^7,8 Histologically, lesions show a lobular panniculitis with a mixed infiltrate. Vasculitis is seen in approximately 90% of erythema induratum cases vs approximately 25% of classic ENL cases (Figure 4),^2,9 which has led some to use the term nodular vasculitis to describe this disease entity. Nodular vasculitis is considered by others to be a distinct disease entity in which there are clinical and histologic features similar to erythema induratum but no evidence of M tuberculosis infection.⁹

Polyarteritis nodosa is a vasculitis that affects medium- sized vessels of various organ systems. The presenting signs and symptoms vary based on the affected organ systems. Palpable to retiform purpura, livedo racemosa, subcutaneous nodules, or ulcers are seen when the skin is involved. The histologic hallmark is necrotizing vasculitis of medium-sized arterioles (Figure 5), although leukocytoclastic vasculitis of small-caliber vessels also can be seen in biopsies of affected skin.¹⁰ The vascular changes are said to be segmental, with uninvolved segments interspersed with involved segments. Antineutrophil cytoplasmic antibody (ANCA)– associated vasculitis also must be considered when one sees leukocytoclastic vasculitis of small-caliber vessels in the skin, as it can be distinguished most readily by detecting circulating antibodies specific for myeloperoxidase (MPO-ANCA) or proteinase 3 (PR3-ANCA).

The Diagnosis: Erythema Nodosum Leprosum

Erythema nodosum leprosum (ENL) is a type 2 reaction sometimes seen in patients infected with Mycobacterium leprae—primarily those with lepromatous or borderline lepromatous subtypes. Clinically, ENL manifests with abrupt onset of tender erythematous papules with associated fevers and general malaise. Studies have demonstrated a complex immune system reaction in ENL, but the detailed pathophysiology is not fully understood.¹ Biopsies conducted within 24 hours of lesion formation are most elucidating. Foamy histiocytes admixed with neutrophils are seen in the subcutis, often causing a lobular panniculitis (quiz image).² Neutrophils rarely are seen in other types of leprosy and thus are a useful diagnostic clue for ENL. Vasculitis of small- to medium-sized vessels can be seen but is not a necessary diagnostic criterion. Fite staining will highlight many acid-fast bacilli within the histiocytes (Figure 1).

Erythema nodosum leprosum is treated with a combination of immunosuppressants such as prednisone and thalidomide. Our patient was taking triple-antibiotic therapy—dapsone, rifampin, and clofazimine—for lepromatous leprosy when the erythematous papules developed on the arms and legs. After a skin biopsy confirmed the diagnosis of ENL, he was started on prednisone 20 mg daily with plans for close follow-up. Unfortunately, the patient was subsequently lost to follow-up.

Acute febrile neutrophilic dermatosis (also known as Sweet syndrome) is an acute inflammatory disease characterized by abrupt onset of painful erythematous papules, plaques, or nodules on the skin. It often is seen in association with preceding infections (especially those in the upper respiratory or gastrointestinal tracts), hematologic malignancies, inflammatory bowel disease, or exposure to certain classes of medications (eg, granulocyte colony-stimulating factor, tyrosine kinase inhibitors, various antibiotics).³ Histologically, acute febrile neutrophilic dermatosis is characterized by dense neutrophilic infiltrates, often with notable dermal edema (Figure 2).⁴ Many cases also show leukocytoclastic vasculitis; however, foamy histiocytes are not a notable component of the inflammatory infiltrate, though a histiocytoid form of acute febrile neutrophilic dermatosis has been described.⁵ Infections must be rigorously ruled out prior to diagnosing a patient with acute febrile neutrophilic dermatosis, making it a diagnosis of exclusion.

Cutaneous coccidioidomycosis is an infection caused by the dimorphic fungi Coccidioides immitis or Coccidioides posadasii. Cutaneous disease is rare but can occur from direct inoculation or dissemination from pulmonary disease in immunocompetent or immunocompromised patients. Papules, pustules, or plaques are seen clinically. Histologically, cutaneous coccidioidomycosis shows spherules that vary from 10 to 100 μm and are filled with multiple smaller endospores (Figure 3).⁶ Pseudoepitheliomatous hyperplasia with dense suppurative and granulomatous infiltrates also is seen.

Erythema induratum is characterized by tender nodules on the lower extremities and has a substantial female predominance. Many cases are associated with Mycobacterium tuberculosis infection. The bacteria are not seen directly in the skin but are instead detectable through DNA polymerase chain reaction testing or investigation of other organ systems.^7,8 Histologically, lesions show a lobular panniculitis with a mixed infiltrate. Vasculitis is seen in approximately 90% of erythema induratum cases vs approximately 25% of classic ENL cases (Figure 4),^2,9 which has led some to use the term nodular vasculitis to describe this disease entity. Nodular vasculitis is considered by others to be a distinct disease entity in which there are clinical and histologic features similar to erythema induratum but no evidence of M tuberculosis infection.⁹

Polyarteritis nodosa is a vasculitis that affects medium- sized vessels of various organ systems. The presenting signs and symptoms vary based on the affected organ systems. Palpable to retiform purpura, livedo racemosa, subcutaneous nodules, or ulcers are seen when the skin is involved. The histologic hallmark is necrotizing vasculitis of medium-sized arterioles (Figure 5), although leukocytoclastic vasculitis of small-caliber vessels also can be seen in biopsies of affected skin.¹⁰ The vascular changes are said to be segmental, with uninvolved segments interspersed with involved segments. Antineutrophil cytoplasmic antibody (ANCA)– associated vasculitis also must be considered when one sees leukocytoclastic vasculitis of small-caliber vessels in the skin, as it can be distinguished most readily by detecting circulating antibodies specific for myeloperoxidase (MPO-ANCA) or proteinase 3 (PR3-ANCA).

The Diagnosis: Erythema Nodosum Leprosum

Erythema nodosum leprosum (ENL) is a type 2 reaction sometimes seen in patients infected with Mycobacterium leprae—primarily those with lepromatous or borderline lepromatous subtypes. Clinically, ENL manifests with abrupt onset of tender erythematous papules with associated fevers and general malaise. Studies have demonstrated a complex immune system reaction in ENL, but the detailed pathophysiology is not fully understood.¹ Biopsies conducted within 24 hours of lesion formation are most elucidating. Foamy histiocytes admixed with neutrophils are seen in the subcutis, often causing a lobular panniculitis (quiz image).² Neutrophils rarely are seen in other types of leprosy and thus are a useful diagnostic clue for ENL. Vasculitis of small- to medium-sized vessels can be seen but is not a necessary diagnostic criterion. Fite staining will highlight many acid-fast bacilli within the histiocytes (Figure 1).

Erythema nodosum leprosum is treated with a combination of immunosuppressants such as prednisone and thalidomide. Our patient was taking triple-antibiotic therapy—dapsone, rifampin, and clofazimine—for lepromatous leprosy when the erythematous papules developed on the arms and legs. After a skin biopsy confirmed the diagnosis of ENL, he was started on prednisone 20 mg daily with plans for close follow-up. Unfortunately, the patient was subsequently lost to follow-up.

Acute febrile neutrophilic dermatosis (also known as Sweet syndrome) is an acute inflammatory disease characterized by abrupt onset of painful erythematous papules, plaques, or nodules on the skin. It often is seen in association with preceding infections (especially those in the upper respiratory or gastrointestinal tracts), hematologic malignancies, inflammatory bowel disease, or exposure to certain classes of medications (eg, granulocyte colony-stimulating factor, tyrosine kinase inhibitors, various antibiotics).³ Histologically, acute febrile neutrophilic dermatosis is characterized by dense neutrophilic infiltrates, often with notable dermal edema (Figure 2).⁴ Many cases also show leukocytoclastic vasculitis; however, foamy histiocytes are not a notable component of the inflammatory infiltrate, though a histiocytoid form of acute febrile neutrophilic dermatosis has been described.⁵ Infections must be rigorously ruled out prior to diagnosing a patient with acute febrile neutrophilic dermatosis, making it a diagnosis of exclusion.

Cutaneous coccidioidomycosis is an infection caused by the dimorphic fungi Coccidioides immitis or Coccidioides posadasii. Cutaneous disease is rare but can occur from direct inoculation or dissemination from pulmonary disease in immunocompetent or immunocompromised patients. Papules, pustules, or plaques are seen clinically. Histologically, cutaneous coccidioidomycosis shows spherules that vary from 10 to 100 μm and are filled with multiple smaller endospores (Figure 3).⁶ Pseudoepitheliomatous hyperplasia with dense suppurative and granulomatous infiltrates also is seen.

Erythema induratum is characterized by tender nodules on the lower extremities and has a substantial female predominance. Many cases are associated with Mycobacterium tuberculosis infection. The bacteria are not seen directly in the skin but are instead detectable through DNA polymerase chain reaction testing or investigation of other organ systems.^7,8 Histologically, lesions show a lobular panniculitis with a mixed infiltrate. Vasculitis is seen in approximately 90% of erythema induratum cases vs approximately 25% of classic ENL cases (Figure 4),^2,9 which has led some to use the term nodular vasculitis to describe this disease entity. Nodular vasculitis is considered by others to be a distinct disease entity in which there are clinical and histologic features similar to erythema induratum but no evidence of M tuberculosis infection.⁹

Polyarteritis nodosa is a vasculitis that affects medium- sized vessels of various organ systems. The presenting signs and symptoms vary based on the affected organ systems. Palpable to retiform purpura, livedo racemosa, subcutaneous nodules, or ulcers are seen when the skin is involved. The histologic hallmark is necrotizing vasculitis of medium-sized arterioles (Figure 5), although leukocytoclastic vasculitis of small-caliber vessels also can be seen in biopsies of affected skin.¹⁰ The vascular changes are said to be segmental, with uninvolved segments interspersed with involved segments. Antineutrophil cytoplasmic antibody (ANCA)– associated vasculitis also must be considered when one sees leukocytoclastic vasculitis of small-caliber vessels in the skin, as it can be distinguished most readily by detecting circulating antibodies specific for myeloperoxidase (MPO-ANCA) or proteinase 3 (PR3-ANCA).

This transcript has been edited for clarity.

In my job, I spend 99% of my time thinking about ethical issues that arise in the care of human beings. That is the focus of our medical school, and that’s what we do. 

However, there are behaviors that are emerging with respect to pets that bear on human health and require the attention of doctors and nurses who deal with people who are pet owners.

Recently, there has been a great increase in the number of pet owners who are saying, “I’m not going to vaccinate my pets.” As horrible as this sounds, what’s happening is vaccine hesitancy about vaccines used in humans is extending through some people to their pets. 

The number of people who say they don’t trust things like rabies vaccine to be effective or safe for their pet animals is 40%, at least in surveys, and the American Veterinary Medical Association reports that 15%-18% of pet owners are not, in fact, vaccinating their pets against rabies.

Rabies, as I hope everybody knows, is one horrible disease. Even the treatment of it, should you get bitten by a rabid animal, is no fun, expensive, and hopefully something that can be administered quickly. It’s not always the case. Worldwide, at least 70,000 people die from rabies every year.

Obviously, there are many countries that are so terrified of rabies, they won’t let you bring pets in without quarantining them, say, England, for at least 6 months to a year, I believe, because they don’t want rabies getting into their country. They’re very strict about the movement of pets.

It is inexcusable for people, first, not to give their pets vaccines that prevent them getting distemper, parvovirus, or many other diseases that harm the pet. It’s also inexcusable to shorten your pet’s life or ask your patients to care for pets who get sick from many of these diseases that are vaccine preventable.

Worst of all, it’s inexcusable for any pet owner not to give a rabies vaccine to their pets. Were it up to me, I’d say you have to license your pet, and as part of that, you must mandate rabies vaccines for your dogs, cats, and other pets. 

We know what happens when people encounter wild animals like raccoons and rabbits. It is not a good situation. Your pets can easily encounter a rabid animal and then put themselves in a position where they can harm their human owners. 

We have an efficacious, safe treatment. If you’re dealing with someone, it might make sense to ask them, “Do you own a pet? Are you vaccinating?” It may not be something you’d ever thought about, but what we don’t need is rabies back in a bigger way in the United States than it’s been in the past.

I think, as a matter of prudence and public health, maybe firing up that question, “Got a pet in the house and are you vaccinating,” could be part of taking a good history.

 

Dr. Caplan is director of the division of medical ethics at New York University Langone Medical Center, New York City. He disclosed conflicts of interest with Johnson & Johnson and Medscape.

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

This transcript has been edited for clarity.

In my job, I spend 99% of my time thinking about ethical issues that arise in the care of human beings. That is the focus of our medical school, and that’s what we do. 

However, there are behaviors that are emerging with respect to pets that bear on human health and require the attention of doctors and nurses who deal with people who are pet owners.

Recently, there has been a great increase in the number of pet owners who are saying, “I’m not going to vaccinate my pets.” As horrible as this sounds, what’s happening is vaccine hesitancy about vaccines used in humans is extending through some people to their pets. 

The number of people who say they don’t trust things like rabies vaccine to be effective or safe for their pet animals is 40%, at least in surveys, and the American Veterinary Medical Association reports that 15%-18% of pet owners are not, in fact, vaccinating their pets against rabies.

Rabies, as I hope everybody knows, is one horrible disease. Even the treatment of it, should you get bitten by a rabid animal, is no fun, expensive, and hopefully something that can be administered quickly. It’s not always the case. Worldwide, at least 70,000 people die from rabies every year.

Obviously, there are many countries that are so terrified of rabies, they won’t let you bring pets in without quarantining them, say, England, for at least 6 months to a year, I believe, because they don’t want rabies getting into their country. They’re very strict about the movement of pets.

It is inexcusable for people, first, not to give their pets vaccines that prevent them getting distemper, parvovirus, or many other diseases that harm the pet. It’s also inexcusable to shorten your pet’s life or ask your patients to care for pets who get sick from many of these diseases that are vaccine preventable.

Worst of all, it’s inexcusable for any pet owner not to give a rabies vaccine to their pets. Were it up to me, I’d say you have to license your pet, and as part of that, you must mandate rabies vaccines for your dogs, cats, and other pets. 

We know what happens when people encounter wild animals like raccoons and rabbits. It is not a good situation. Your pets can easily encounter a rabid animal and then put themselves in a position where they can harm their human owners. 

We have an efficacious, safe treatment. If you’re dealing with someone, it might make sense to ask them, “Do you own a pet? Are you vaccinating?” It may not be something you’d ever thought about, but what we don’t need is rabies back in a bigger way in the United States than it’s been in the past.

I think, as a matter of prudence and public health, maybe firing up that question, “Got a pet in the house and are you vaccinating,” could be part of taking a good history.

 

Dr. Caplan is director of the division of medical ethics at New York University Langone Medical Center, New York City. He disclosed conflicts of interest with Johnson & Johnson and Medscape.

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

This transcript has been edited for clarity.

In my job, I spend 99% of my time thinking about ethical issues that arise in the care of human beings. That is the focus of our medical school, and that’s what we do. 

However, there are behaviors that are emerging with respect to pets that bear on human health and require the attention of doctors and nurses who deal with people who are pet owners.

Recently, there has been a great increase in the number of pet owners who are saying, “I’m not going to vaccinate my pets.” As horrible as this sounds, what’s happening is vaccine hesitancy about vaccines used in humans is extending through some people to their pets. 

The number of people who say they don’t trust things like rabies vaccine to be effective or safe for their pet animals is 40%, at least in surveys, and the American Veterinary Medical Association reports that 15%-18% of pet owners are not, in fact, vaccinating their pets against rabies.

Rabies, as I hope everybody knows, is one horrible disease. Even the treatment of it, should you get bitten by a rabid animal, is no fun, expensive, and hopefully something that can be administered quickly. It’s not always the case. Worldwide, at least 70,000 people die from rabies every year.

Obviously, there are many countries that are so terrified of rabies, they won’t let you bring pets in without quarantining them, say, England, for at least 6 months to a year, I believe, because they don’t want rabies getting into their country. They’re very strict about the movement of pets.

It is inexcusable for people, first, not to give their pets vaccines that prevent them getting distemper, parvovirus, or many other diseases that harm the pet. It’s also inexcusable to shorten your pet’s life or ask your patients to care for pets who get sick from many of these diseases that are vaccine preventable.

Worst of all, it’s inexcusable for any pet owner not to give a rabies vaccine to their pets. Were it up to me, I’d say you have to license your pet, and as part of that, you must mandate rabies vaccines for your dogs, cats, and other pets. 

We know what happens when people encounter wild animals like raccoons and rabbits. It is not a good situation. Your pets can easily encounter a rabid animal and then put themselves in a position where they can harm their human owners. 

We have an efficacious, safe treatment. If you’re dealing with someone, it might make sense to ask them, “Do you own a pet? Are you vaccinating?” It may not be something you’d ever thought about, but what we don’t need is rabies back in a bigger way in the United States than it’s been in the past.

I think, as a matter of prudence and public health, maybe firing up that question, “Got a pet in the house and are you vaccinating,” could be part of taking a good history.

 

Dr. Caplan is director of the division of medical ethics at New York University Langone Medical Center, New York City. He disclosed conflicts of interest with Johnson & Johnson and Medscape.

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

TOPLINE:

The prevalence of recurrent urinary tract infections (rUTIs) and the use of antibiotics for prevention are substantial among women in Wales, particularly among those over the age of 57 years. A high level of resistance to two recommended antibiotics was observed, suggesting that more frequent urine cultures could better guide antibiotic selection for treatment and prophylaxis.

METHODOLOGY:

• The researchers conducted a retrospective cross-sectional study using a large databank of patients in Wales to describe the characteristics and urine profiles of women with rUTIs between 2010 and 2022.
• They created two cohorts: One with 92,213 women (median age, 60 years) who experienced rUTIs, defined as two or more acute episodes within 6 months or three or more acute episodes within 12 months.
• Another cohort comprised of 26,862 women (median age, 71 years) were prescribed prophylactic antibiotics, which was defined as receiving three or more consecutive prescriptions of the same UTI-specific antibiotic (trimethoprim, nitrofurantoin, or cefalexin), with intervals of 21-56 days between prescriptions.
• Urine culture results in the 12 months before a rUTI diagnosis and 18 months before prophylactic antibiotic initiation and all urine culture results within 7 days of an acute UTI were analyzed to assess antibiotic resistance patterns.

TAKEAWAY:

• Overall, 6% of women had rUTIs, 1.7% of which were prescribed prophylactic antibiotics with proportions increasing sharply after age 57.
• Nearly half of the women (49%) who were prescribed a prophylactic antibiotic qualified as having rUTIs in the 18 months before initiation.
• This study showed that 80.8% of women with rUTIs had a urine culture result documented in the 12 months preceding the diagnosis.
• More than half (64%) of the women taking prophylactic antibiotics had a urine culture result documented before starting treatment, and 18% of those prescribed trimethoprim had resistance to the antibiotic.

IN PRACTICE:

“More frequent urine cultures in the workup of rUTI diagnosis and prophylactic antibiotic initiation could better inform antibiotic choice,” the authors wrote.

SOURCE:

The study was led by Leigh Sanyaolu, BSc (Hons), MRCS, MRCGP, PGDip, a general practitioner from the Division of Population Medicine and PRIME Centre Wales at Cardiff University in Cardiff, and was published online in the British Journal of General Practice.

LIMITATIONS:

The study’s reliance on electronic health records may have led to coding errors and missing data. The diagnosis of UTIs may have been difficult in older women with increased frailty as they can have fewer specific symptoms and asymptomatic bacteriuria, which can be misdiagnosed as a UTI.

DISCLOSURES:

This work was supported by Health and Care Research Wales. The authors declared no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

The prevalence of recurrent urinary tract infections (rUTIs) and the use of antibiotics for prevention are substantial among women in Wales, particularly among those over the age of 57 years. A high level of resistance to two recommended antibiotics was observed, suggesting that more frequent urine cultures could better guide antibiotic selection for treatment and prophylaxis.

METHODOLOGY:

• The researchers conducted a retrospective cross-sectional study using a large databank of patients in Wales to describe the characteristics and urine profiles of women with rUTIs between 2010 and 2022.
• They created two cohorts: One with 92,213 women (median age, 60 years) who experienced rUTIs, defined as two or more acute episodes within 6 months or three or more acute episodes within 12 months.
• Another cohort comprised of 26,862 women (median age, 71 years) were prescribed prophylactic antibiotics, which was defined as receiving three or more consecutive prescriptions of the same UTI-specific antibiotic (trimethoprim, nitrofurantoin, or cefalexin), with intervals of 21-56 days between prescriptions.
• Urine culture results in the 12 months before a rUTI diagnosis and 18 months before prophylactic antibiotic initiation and all urine culture results within 7 days of an acute UTI were analyzed to assess antibiotic resistance patterns.

TAKEAWAY:

• Overall, 6% of women had rUTIs, 1.7% of which were prescribed prophylactic antibiotics with proportions increasing sharply after age 57.
• Nearly half of the women (49%) who were prescribed a prophylactic antibiotic qualified as having rUTIs in the 18 months before initiation.
• This study showed that 80.8% of women with rUTIs had a urine culture result documented in the 12 months preceding the diagnosis.
• More than half (64%) of the women taking prophylactic antibiotics had a urine culture result documented before starting treatment, and 18% of those prescribed trimethoprim had resistance to the antibiotic.

IN PRACTICE:

“More frequent urine cultures in the workup of rUTI diagnosis and prophylactic antibiotic initiation could better inform antibiotic choice,” the authors wrote.

SOURCE:

The study was led by Leigh Sanyaolu, BSc (Hons), MRCS, MRCGP, PGDip, a general practitioner from the Division of Population Medicine and PRIME Centre Wales at Cardiff University in Cardiff, and was published online in the British Journal of General Practice.

LIMITATIONS:

The study’s reliance on electronic health records may have led to coding errors and missing data. The diagnosis of UTIs may have been difficult in older women with increased frailty as they can have fewer specific symptoms and asymptomatic bacteriuria, which can be misdiagnosed as a UTI.

DISCLOSURES:

This work was supported by Health and Care Research Wales. The authors declared no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

The prevalence of recurrent urinary tract infections (rUTIs) and the use of antibiotics for prevention are substantial among women in Wales, particularly among those over the age of 57 years. A high level of resistance to two recommended antibiotics was observed, suggesting that more frequent urine cultures could better guide antibiotic selection for treatment and prophylaxis.

METHODOLOGY:

• The researchers conducted a retrospective cross-sectional study using a large databank of patients in Wales to describe the characteristics and urine profiles of women with rUTIs between 2010 and 2022.
• They created two cohorts: One with 92,213 women (median age, 60 years) who experienced rUTIs, defined as two or more acute episodes within 6 months or three or more acute episodes within 12 months.
• Another cohort comprised of 26,862 women (median age, 71 years) were prescribed prophylactic antibiotics, which was defined as receiving three or more consecutive prescriptions of the same UTI-specific antibiotic (trimethoprim, nitrofurantoin, or cefalexin), with intervals of 21-56 days between prescriptions.
• Urine culture results in the 12 months before a rUTI diagnosis and 18 months before prophylactic antibiotic initiation and all urine culture results within 7 days of an acute UTI were analyzed to assess antibiotic resistance patterns.

TAKEAWAY:

• Overall, 6% of women had rUTIs, 1.7% of which were prescribed prophylactic antibiotics with proportions increasing sharply after age 57.
• Nearly half of the women (49%) who were prescribed a prophylactic antibiotic qualified as having rUTIs in the 18 months before initiation.
• This study showed that 80.8% of women with rUTIs had a urine culture result documented in the 12 months preceding the diagnosis.
• More than half (64%) of the women taking prophylactic antibiotics had a urine culture result documented before starting treatment, and 18% of those prescribed trimethoprim had resistance to the antibiotic.

IN PRACTICE:

“More frequent urine cultures in the workup of rUTI diagnosis and prophylactic antibiotic initiation could better inform antibiotic choice,” the authors wrote.

SOURCE:

The study was led by Leigh Sanyaolu, BSc (Hons), MRCS, MRCGP, PGDip, a general practitioner from the Division of Population Medicine and PRIME Centre Wales at Cardiff University in Cardiff, and was published online in the British Journal of General Practice.

LIMITATIONS:

The study’s reliance on electronic health records may have led to coding errors and missing data. The diagnosis of UTIs may have been difficult in older women with increased frailty as they can have fewer specific symptoms and asymptomatic bacteriuria, which can be misdiagnosed as a UTI.

DISCLOSURES:

This work was supported by Health and Care Research Wales. The authors declared no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

Vaccines work pretty well. But with a little help, they could work better.

Stanford researchers have developed a new vaccine helper that combines two kinds of adjuvants, ingredients that improve a vaccine’s efficacy, in a novel, customizable system.

In lab tests, the experimental additive improved the effectiveness of COVID-19 and HIV vaccine candidates, though it could be adapted to stimulate immune responses to a variety of pathogens, the researchers said. It could also be used one day to fine-tune vaccines for vulnerable groups like young children, older adults, and those with compromised immune systems.

“Current vaccines are not perfect,” said lead study author Ben Ou, a PhD candidate and researcher in the lab of Eric Appel, PhD, an associate professor of materials science and engineering, at Stanford University in California. “Many fail to generate long-lasting immunity or immunity against closely related strains [such as] flu or COVID vaccines. One way to improve them is to design more potent vaccine adjuvants.”

The study marks an advance in an area of growing scientific interest: Combining different adjuvants to enhance the immune-stimulating effect.

The Stanford scientists developed sphere-shaped nanoparticles, like tiny round cages, made of saponins, immune-stimulating molecules common in adjuvant development. To these nanoparticles, they attached Toll-like receptor (TLR) agonists, molecules that have become a focus in vaccine research because they stimulate a variety of immune responses.

Dr. Ou and the team tested the new adjuvant platform in COVID and HIV vaccines, comparing it to vaccines containing alum, a widely used adjuvant. (Alum is not used in COVID vaccines available in the United States.)

The nanoparticle-adjuvanted vaccines triggered stronger, longer-lasting effects. 

Notably, the combination of the new adjuvant system with a SARS-CoV-2 virus vaccine was effective in mice against the original SARS-CoV-2 virus and against Delta, Omicron, and other variants that emerged in the months and years after the initial outbreak. 

“Since our nanoparticle adjuvant platform is more potent than traditional/clinical vaccine adjuvants,” Dr. Ou said, “we expected mice to produce broadly neutralizing antibodies and better breadth responses.”
 

100 Years of Adjuvants

The first vaccine adjuvants were aluminum salts mixed into shots against pertussis, diphtheria, and tetanus in the 1920s. Today, alum is still used in many vaccines, including shots for diphtheria, tetanus, and pertussis; hepatitis A and B; human papillomavirus; and pneumococcal disease.

But since the 1990s, new adjuvants have come on the scene. Saponin-based compounds, harvested from the soapbark tree, are used in the Novavax COVID-19 Vaccine, Adjuvanted; a synthetic DNA adjuvant in the Heplisav-B vaccine against hepatitis B; and oil in water adjuvants using squalene in the Fluad and Fluad Quadrivalent influenza vaccines. Other vaccines, including those for chickenpox, cholera, measles, mumps, rubella, and mRNA-based COVID vaccines from Pfizer-BioNTech and Moderna, don’t contain adjuvants. 

TLR agonists have recently become research hotspots in vaccine science. 

“TLR agonists activate the innate immune system, putting it on a heightened alert state that can result in a higher antibody production and longer-lasting protection,” said David Burkhart, PhD, a research professor in biomedical and pharmaceutical sciences at the University of Montana in Missoula. He is also the chief operating officer of Inimmune, a biotech company developing vaccines and immunotherapies.

Dr. Burkhart studies TLR agonists in vaccines and other applications. “Different combinations activate different parts of the immune system,” he said. “TLR4 might activate the army, while TLR7 might activate the air force. You might need both in one vaccine.”

TLR agonists have also shown promise against Alzheimer’s disease, allergies, cancer, and even addiction. In immune’s experimental immunotherapy using TLR agonists for advanced solid tumors has just entered human trials, and the company is looking at a TLR agonist therapy for allergic rhinitis. 
 

Combining Forces

In the new study, researchers tested five different combinations of TLR agonists hooked to the saponin nanoparticle framework. Each elicited a slightly different response from the immune cells. 

“Our immune systems generate different downstream immune responses based on which TLRs are activated,” Dr. Ou said.

Ultimately, the advance could spur the development of vaccines tuned for stronger immune protection.

“We need different immune responses to fight different types of pathogens,” Dr. Ou said. “Depending on what specific virus/disease the vaccine is formulated for, activation of one specific TLR may confer better protection than another TLR.”

According to Dr. Burkhart, combining a saponin with a TLR agonist has found success before.

Biopharma company GSK (formerly GlaxoSmithKline) used the combination in its AS01 adjuvant, in the vaccine Shingrix against herpes zoster. The live-attenuated yellow fever vaccine, given to more than 600 million people around the world and considered one of the most powerful vaccines ever developed, uses several TLR agonists. 

The Stanford paper, Dr. Burkhart said, “is a nice demonstration of the enhanced efficacy [that] adjuvants can provide to vaccines by exploiting the synergy different adjuvants and TLR agonists can provide when used in combination.”
 

Tailoring Vaccines

The customizable aspect of TLR agonists is important too, Dr. Burkhart said. 

“The human immune system changes dramatically from birth to childhood into adulthood into older maturity,” he said. “It’s not a one-size-fits-all. Vaccines need to be tailored to these populations for maximum effectiveness and safety. TLRAs [TLR agonists] are a highly valuable tool in the vaccine toolbox. I think it’s inevitable we’ll have more in the future.”

That’s what the Stanford researchers hope for.

They noted in the study that the nanoparticle platform could easily be used to test different TLR agonist adjuvant combinations in vaccines.

But human studies are still a ways off. Tests in larger animals would likely come next, Dr. Ou said. 

“We now have a single nanoparticle adjuvant platform with formulations containing different TLRs,” Dr. Ou said. “Scientists can pick which specific formulation is the most suitable for their needs.”

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

Vaccines work pretty well. But with a little help, they could work better.

Stanford researchers have developed a new vaccine helper that combines two kinds of adjuvants, ingredients that improve a vaccine’s efficacy, in a novel, customizable system.

In lab tests, the experimental additive improved the effectiveness of COVID-19 and HIV vaccine candidates, though it could be adapted to stimulate immune responses to a variety of pathogens, the researchers said. It could also be used one day to fine-tune vaccines for vulnerable groups like young children, older adults, and those with compromised immune systems.

“Current vaccines are not perfect,” said lead study author Ben Ou, a PhD candidate and researcher in the lab of Eric Appel, PhD, an associate professor of materials science and engineering, at Stanford University in California. “Many fail to generate long-lasting immunity or immunity against closely related strains [such as] flu or COVID vaccines. One way to improve them is to design more potent vaccine adjuvants.”

The study marks an advance in an area of growing scientific interest: Combining different adjuvants to enhance the immune-stimulating effect.

The Stanford scientists developed sphere-shaped nanoparticles, like tiny round cages, made of saponins, immune-stimulating molecules common in adjuvant development. To these nanoparticles, they attached Toll-like receptor (TLR) agonists, molecules that have become a focus in vaccine research because they stimulate a variety of immune responses.

Dr. Ou and the team tested the new adjuvant platform in COVID and HIV vaccines, comparing it to vaccines containing alum, a widely used adjuvant. (Alum is not used in COVID vaccines available in the United States.)

The nanoparticle-adjuvanted vaccines triggered stronger, longer-lasting effects. 

Notably, the combination of the new adjuvant system with a SARS-CoV-2 virus vaccine was effective in mice against the original SARS-CoV-2 virus and against Delta, Omicron, and other variants that emerged in the months and years after the initial outbreak. 

“Since our nanoparticle adjuvant platform is more potent than traditional/clinical vaccine adjuvants,” Dr. Ou said, “we expected mice to produce broadly neutralizing antibodies and better breadth responses.”
 

100 Years of Adjuvants

The first vaccine adjuvants were aluminum salts mixed into shots against pertussis, diphtheria, and tetanus in the 1920s. Today, alum is still used in many vaccines, including shots for diphtheria, tetanus, and pertussis; hepatitis A and B; human papillomavirus; and pneumococcal disease.

But since the 1990s, new adjuvants have come on the scene. Saponin-based compounds, harvested from the soapbark tree, are used in the Novavax COVID-19 Vaccine, Adjuvanted; a synthetic DNA adjuvant in the Heplisav-B vaccine against hepatitis B; and oil in water adjuvants using squalene in the Fluad and Fluad Quadrivalent influenza vaccines. Other vaccines, including those for chickenpox, cholera, measles, mumps, rubella, and mRNA-based COVID vaccines from Pfizer-BioNTech and Moderna, don’t contain adjuvants. 

TLR agonists have recently become research hotspots in vaccine science. 

“TLR agonists activate the innate immune system, putting it on a heightened alert state that can result in a higher antibody production and longer-lasting protection,” said David Burkhart, PhD, a research professor in biomedical and pharmaceutical sciences at the University of Montana in Missoula. He is also the chief operating officer of Inimmune, a biotech company developing vaccines and immunotherapies.

Dr. Burkhart studies TLR agonists in vaccines and other applications. “Different combinations activate different parts of the immune system,” he said. “TLR4 might activate the army, while TLR7 might activate the air force. You might need both in one vaccine.”

TLR agonists have also shown promise against Alzheimer’s disease, allergies, cancer, and even addiction. In immune’s experimental immunotherapy using TLR agonists for advanced solid tumors has just entered human trials, and the company is looking at a TLR agonist therapy for allergic rhinitis. 
 

Combining Forces

In the new study, researchers tested five different combinations of TLR agonists hooked to the saponin nanoparticle framework. Each elicited a slightly different response from the immune cells. 

“Our immune systems generate different downstream immune responses based on which TLRs are activated,” Dr. Ou said.

Ultimately, the advance could spur the development of vaccines tuned for stronger immune protection.

“We need different immune responses to fight different types of pathogens,” Dr. Ou said. “Depending on what specific virus/disease the vaccine is formulated for, activation of one specific TLR may confer better protection than another TLR.”

According to Dr. Burkhart, combining a saponin with a TLR agonist has found success before.

Biopharma company GSK (formerly GlaxoSmithKline) used the combination in its AS01 adjuvant, in the vaccine Shingrix against herpes zoster. The live-attenuated yellow fever vaccine, given to more than 600 million people around the world and considered one of the most powerful vaccines ever developed, uses several TLR agonists. 

The Stanford paper, Dr. Burkhart said, “is a nice demonstration of the enhanced efficacy [that] adjuvants can provide to vaccines by exploiting the synergy different adjuvants and TLR agonists can provide when used in combination.”
 

Tailoring Vaccines

The customizable aspect of TLR agonists is important too, Dr. Burkhart said. 

“The human immune system changes dramatically from birth to childhood into adulthood into older maturity,” he said. “It’s not a one-size-fits-all. Vaccines need to be tailored to these populations for maximum effectiveness and safety. TLRAs [TLR agonists] are a highly valuable tool in the vaccine toolbox. I think it’s inevitable we’ll have more in the future.”

That’s what the Stanford researchers hope for.

They noted in the study that the nanoparticle platform could easily be used to test different TLR agonist adjuvant combinations in vaccines.

But human studies are still a ways off. Tests in larger animals would likely come next, Dr. Ou said. 

“We now have a single nanoparticle adjuvant platform with formulations containing different TLRs,” Dr. Ou said. “Scientists can pick which specific formulation is the most suitable for their needs.”

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

Vaccines work pretty well. But with a little help, they could work better.

Stanford researchers have developed a new vaccine helper that combines two kinds of adjuvants, ingredients that improve a vaccine’s efficacy, in a novel, customizable system.

In lab tests, the experimental additive improved the effectiveness of COVID-19 and HIV vaccine candidates, though it could be adapted to stimulate immune responses to a variety of pathogens, the researchers said. It could also be used one day to fine-tune vaccines for vulnerable groups like young children, older adults, and those with compromised immune systems.

“Current vaccines are not perfect,” said lead study author Ben Ou, a PhD candidate and researcher in the lab of Eric Appel, PhD, an associate professor of materials science and engineering, at Stanford University in California. “Many fail to generate long-lasting immunity or immunity against closely related strains [such as] flu or COVID vaccines. One way to improve them is to design more potent vaccine adjuvants.”

The study marks an advance in an area of growing scientific interest: Combining different adjuvants to enhance the immune-stimulating effect.

The Stanford scientists developed sphere-shaped nanoparticles, like tiny round cages, made of saponins, immune-stimulating molecules common in adjuvant development. To these nanoparticles, they attached Toll-like receptor (TLR) agonists, molecules that have become a focus in vaccine research because they stimulate a variety of immune responses.

Dr. Ou and the team tested the new adjuvant platform in COVID and HIV vaccines, comparing it to vaccines containing alum, a widely used adjuvant. (Alum is not used in COVID vaccines available in the United States.)

The nanoparticle-adjuvanted vaccines triggered stronger, longer-lasting effects. 

Notably, the combination of the new adjuvant system with a SARS-CoV-2 virus vaccine was effective in mice against the original SARS-CoV-2 virus and against Delta, Omicron, and other variants that emerged in the months and years after the initial outbreak. 

“Since our nanoparticle adjuvant platform is more potent than traditional/clinical vaccine adjuvants,” Dr. Ou said, “we expected mice to produce broadly neutralizing antibodies and better breadth responses.”
 

100 Years of Adjuvants

The first vaccine adjuvants were aluminum salts mixed into shots against pertussis, diphtheria, and tetanus in the 1920s. Today, alum is still used in many vaccines, including shots for diphtheria, tetanus, and pertussis; hepatitis A and B; human papillomavirus; and pneumococcal disease.

But since the 1990s, new adjuvants have come on the scene. Saponin-based compounds, harvested from the soapbark tree, are used in the Novavax COVID-19 Vaccine, Adjuvanted; a synthetic DNA adjuvant in the Heplisav-B vaccine against hepatitis B; and oil in water adjuvants using squalene in the Fluad and Fluad Quadrivalent influenza vaccines. Other vaccines, including those for chickenpox, cholera, measles, mumps, rubella, and mRNA-based COVID vaccines from Pfizer-BioNTech and Moderna, don’t contain adjuvants. 

TLR agonists have recently become research hotspots in vaccine science. 

“TLR agonists activate the innate immune system, putting it on a heightened alert state that can result in a higher antibody production and longer-lasting protection,” said David Burkhart, PhD, a research professor in biomedical and pharmaceutical sciences at the University of Montana in Missoula. He is also the chief operating officer of Inimmune, a biotech company developing vaccines and immunotherapies.

Dr. Burkhart studies TLR agonists in vaccines and other applications. “Different combinations activate different parts of the immune system,” he said. “TLR4 might activate the army, while TLR7 might activate the air force. You might need both in one vaccine.”

TLR agonists have also shown promise against Alzheimer’s disease, allergies, cancer, and even addiction. In immune’s experimental immunotherapy using TLR agonists for advanced solid tumors has just entered human trials, and the company is looking at a TLR agonist therapy for allergic rhinitis. 
 

Combining Forces

In the new study, researchers tested five different combinations of TLR agonists hooked to the saponin nanoparticle framework. Each elicited a slightly different response from the immune cells. 

“Our immune systems generate different downstream immune responses based on which TLRs are activated,” Dr. Ou said.

Ultimately, the advance could spur the development of vaccines tuned for stronger immune protection.

“We need different immune responses to fight different types of pathogens,” Dr. Ou said. “Depending on what specific virus/disease the vaccine is formulated for, activation of one specific TLR may confer better protection than another TLR.”

According to Dr. Burkhart, combining a saponin with a TLR agonist has found success before.

Biopharma company GSK (formerly GlaxoSmithKline) used the combination in its AS01 adjuvant, in the vaccine Shingrix against herpes zoster. The live-attenuated yellow fever vaccine, given to more than 600 million people around the world and considered one of the most powerful vaccines ever developed, uses several TLR agonists. 

The Stanford paper, Dr. Burkhart said, “is a nice demonstration of the enhanced efficacy [that] adjuvants can provide to vaccines by exploiting the synergy different adjuvants and TLR agonists can provide when used in combination.”
 

Tailoring Vaccines

The customizable aspect of TLR agonists is important too, Dr. Burkhart said. 

“The human immune system changes dramatically from birth to childhood into adulthood into older maturity,” he said. “It’s not a one-size-fits-all. Vaccines need to be tailored to these populations for maximum effectiveness and safety. TLRAs [TLR agonists] are a highly valuable tool in the vaccine toolbox. I think it’s inevitable we’ll have more in the future.”

That’s what the Stanford researchers hope for.

They noted in the study that the nanoparticle platform could easily be used to test different TLR agonist adjuvant combinations in vaccines.

But human studies are still a ways off. Tests in larger animals would likely come next, Dr. Ou said. 

“We now have a single nanoparticle adjuvant platform with formulations containing different TLRs,” Dr. Ou said. “Scientists can pick which specific formulation is the most suitable for their needs.”

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

Scientists at Stanford University and the University of Pennsylvania have discovered a new antibiotic candidate in a surprising place: the human gut. 

In mice, the antibiotic — a peptide known as prevotellin-2 — showed antimicrobial potency on par with polymyxin B, an antibiotic medication used to treat multidrug-resistant infections. Meanwhile, the peptide mainly left commensal, or beneficial, bacteria alone. The study, published in Cell, also identified several other potent antibiotic peptides with the potential to combat antimicrobial-resistant infections.

The research is part of a larger quest to find new antibiotics that can fight drug-resistant infections, a critical public health threat with more than 2.8 million cases and 35,000 deaths annually in the United States. That quest is urgent, said study author César de la Fuente, PhD, professor of bioengineering at the University of Pennsylvania, Philadelphia. 

“The main pillars that have enabled us to almost double our lifespan in the last 100 years or so have been antibiotics, vaccines, and clean water,” said Dr. de la Fuente. “Imagine taking out one of those. I think it would be pretty dramatic.” (Dr. De la Fuente’s lab has become known for finding antibiotic candidates in unusual places, like ancient genetic information of Neanderthals and woolly mammoths.)  

The first widely used antibiotic, penicillin, was discovered in 1928, when a physician studying Staphylococcus bacteria returned to his lab after summer break to find mold growing in one of his petri dishes. But many other antibiotics — like streptomycin, tetracycline, and erythromycin — were discovered from soil bacteria, which produce variations of these substances to compete with other microorganisms. 

By looking in the gut microbiome, the researchers hoped to identify peptides that the trillions of microbes use against each other in the fight for limited resources — ideally, peptides that wouldn’t broadly kill off the entire microbiome. 
 

Kill the Bad, Spare the Good

Many traditional antibiotics are small molecules. This means they can wipe out the good bacteria in your body, and because each targets a specific bacterial function, bad bacteria can become resistant to them.

Peptide antibiotics, on the other hand, don’t diffuse into the whole body. If taken orally, they stay in the gut; if taken intravenously, they generally stay in the blood. And because of how they kill bacteria, targeting the membrane, they’re also less prone to bacterial resistance.

The microbiome is like a big reservoir of pathogens, said Ami Bhatt, MD, PhD, hematologist at Stanford University in California and one of the study’s authors. Because many antibiotics kill healthy gut bacteria, “what you have left over,” Dr. Bhatt said, “is this big open niche that gets filled up with multidrug-resistant organisms like E coli [Escherichia coli] or vancomycin-resistant Enterococcus.”

Dr. Bhatt has seen cancer patients undergo successful treatment only to die of a multidrug-resistant infection, because current antibiotics fail against those pathogens. “That’s like winning the battle to lose the war.”

By investigating the microbiome, “we wanted to see if we could identify antimicrobial peptides that might spare key members of our regular microbiome, so that we wouldn’t totally disrupt the microbiome the way we do when we use broad-spectrum, small molecule–based antibiotics,” Dr. Bhatt said.

The researchers used artificial intelligence to sift through 400,000 proteins to predict, based on known antibiotics, which peptide sequences might have antimicrobial properties. From the results, they chose 78 peptides to synthesize and test.

“The application of computational approaches combined with experimental validation is very powerful and exciting,” said Jennifer Geddes-McAlister, PhD, professor of cell biology at the University of Guelph in Ontario, Canada, who was not involved in the study. “The study is robust in its approach to microbiome sampling.” 
 

The Long Journey from Lab to Clinic

More than half of the peptides the team tested effectively inhibited the growth of harmful bacteria, and prevotellin-2 (derived from the bacteria Prevotella copri)stood out as the most powerful.

“The study validates experimental data from the lab using animal models, which moves discoveries closer to the clinic,” said Dr. Geddes-McAlister. “Further testing with clinical trials is needed, but the potential for clinical application is promising.” 

Unfortunately, that’s not likely to happen anytime soon, said Dr. de la Fuente. “There is not enough economic incentive” for companies to develop new antibiotics. Ten years is his most hopeful guess for when we might see prevotellin-2, or a similar antibiotic, complete clinical trials.

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

Scientists at Stanford University and the University of Pennsylvania have discovered a new antibiotic candidate in a surprising place: the human gut. 

In mice, the antibiotic — a peptide known as prevotellin-2 — showed antimicrobial potency on par with polymyxin B, an antibiotic medication used to treat multidrug-resistant infections. Meanwhile, the peptide mainly left commensal, or beneficial, bacteria alone. The study, published in Cell, also identified several other potent antibiotic peptides with the potential to combat antimicrobial-resistant infections.

The research is part of a larger quest to find new antibiotics that can fight drug-resistant infections, a critical public health threat with more than 2.8 million cases and 35,000 deaths annually in the United States. That quest is urgent, said study author César de la Fuente, PhD, professor of bioengineering at the University of Pennsylvania, Philadelphia. 

“The main pillars that have enabled us to almost double our lifespan in the last 100 years or so have been antibiotics, vaccines, and clean water,” said Dr. de la Fuente. “Imagine taking out one of those. I think it would be pretty dramatic.” (Dr. De la Fuente’s lab has become known for finding antibiotic candidates in unusual places, like ancient genetic information of Neanderthals and woolly mammoths.)  

The first widely used antibiotic, penicillin, was discovered in 1928, when a physician studying Staphylococcus bacteria returned to his lab after summer break to find mold growing in one of his petri dishes. But many other antibiotics — like streptomycin, tetracycline, and erythromycin — were discovered from soil bacteria, which produce variations of these substances to compete with other microorganisms. 

By looking in the gut microbiome, the researchers hoped to identify peptides that the trillions of microbes use against each other in the fight for limited resources — ideally, peptides that wouldn’t broadly kill off the entire microbiome. 
 

Kill the Bad, Spare the Good

Many traditional antibiotics are small molecules. This means they can wipe out the good bacteria in your body, and because each targets a specific bacterial function, bad bacteria can become resistant to them.

Peptide antibiotics, on the other hand, don’t diffuse into the whole body. If taken orally, they stay in the gut; if taken intravenously, they generally stay in the blood. And because of how they kill bacteria, targeting the membrane, they’re also less prone to bacterial resistance.

The microbiome is like a big reservoir of pathogens, said Ami Bhatt, MD, PhD, hematologist at Stanford University in California and one of the study’s authors. Because many antibiotics kill healthy gut bacteria, “what you have left over,” Dr. Bhatt said, “is this big open niche that gets filled up with multidrug-resistant organisms like E coli [Escherichia coli] or vancomycin-resistant Enterococcus.”

Dr. Bhatt has seen cancer patients undergo successful treatment only to die of a multidrug-resistant infection, because current antibiotics fail against those pathogens. “That’s like winning the battle to lose the war.”

By investigating the microbiome, “we wanted to see if we could identify antimicrobial peptides that might spare key members of our regular microbiome, so that we wouldn’t totally disrupt the microbiome the way we do when we use broad-spectrum, small molecule–based antibiotics,” Dr. Bhatt said.

The researchers used artificial intelligence to sift through 400,000 proteins to predict, based on known antibiotics, which peptide sequences might have antimicrobial properties. From the results, they chose 78 peptides to synthesize and test.

“The application of computational approaches combined with experimental validation is very powerful and exciting,” said Jennifer Geddes-McAlister, PhD, professor of cell biology at the University of Guelph in Ontario, Canada, who was not involved in the study. “The study is robust in its approach to microbiome sampling.” 
 

The Long Journey from Lab to Clinic

More than half of the peptides the team tested effectively inhibited the growth of harmful bacteria, and prevotellin-2 (derived from the bacteria Prevotella copri)stood out as the most powerful.

“The study validates experimental data from the lab using animal models, which moves discoveries closer to the clinic,” said Dr. Geddes-McAlister. “Further testing with clinical trials is needed, but the potential for clinical application is promising.” 

Unfortunately, that’s not likely to happen anytime soon, said Dr. de la Fuente. “There is not enough economic incentive” for companies to develop new antibiotics. Ten years is his most hopeful guess for when we might see prevotellin-2, or a similar antibiotic, complete clinical trials.

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

Scientists at Stanford University and the University of Pennsylvania have discovered a new antibiotic candidate in a surprising place: the human gut. 

In mice, the antibiotic — a peptide known as prevotellin-2 — showed antimicrobial potency on par with polymyxin B, an antibiotic medication used to treat multidrug-resistant infections. Meanwhile, the peptide mainly left commensal, or beneficial, bacteria alone. The study, published in Cell, also identified several other potent antibiotic peptides with the potential to combat antimicrobial-resistant infections.

The research is part of a larger quest to find new antibiotics that can fight drug-resistant infections, a critical public health threat with more than 2.8 million cases and 35,000 deaths annually in the United States. That quest is urgent, said study author César de la Fuente, PhD, professor of bioengineering at the University of Pennsylvania, Philadelphia. 

“The main pillars that have enabled us to almost double our lifespan in the last 100 years or so have been antibiotics, vaccines, and clean water,” said Dr. de la Fuente. “Imagine taking out one of those. I think it would be pretty dramatic.” (Dr. De la Fuente’s lab has become known for finding antibiotic candidates in unusual places, like ancient genetic information of Neanderthals and woolly mammoths.)  

The first widely used antibiotic, penicillin, was discovered in 1928, when a physician studying Staphylococcus bacteria returned to his lab after summer break to find mold growing in one of his petri dishes. But many other antibiotics — like streptomycin, tetracycline, and erythromycin — were discovered from soil bacteria, which produce variations of these substances to compete with other microorganisms. 

By looking in the gut microbiome, the researchers hoped to identify peptides that the trillions of microbes use against each other in the fight for limited resources — ideally, peptides that wouldn’t broadly kill off the entire microbiome. 
 

Kill the Bad, Spare the Good

Many traditional antibiotics are small molecules. This means they can wipe out the good bacteria in your body, and because each targets a specific bacterial function, bad bacteria can become resistant to them.

Peptide antibiotics, on the other hand, don’t diffuse into the whole body. If taken orally, they stay in the gut; if taken intravenously, they generally stay in the blood. And because of how they kill bacteria, targeting the membrane, they’re also less prone to bacterial resistance.

The microbiome is like a big reservoir of pathogens, said Ami Bhatt, MD, PhD, hematologist at Stanford University in California and one of the study’s authors. Because many antibiotics kill healthy gut bacteria, “what you have left over,” Dr. Bhatt said, “is this big open niche that gets filled up with multidrug-resistant organisms like E coli [Escherichia coli] or vancomycin-resistant Enterococcus.”

Dr. Bhatt has seen cancer patients undergo successful treatment only to die of a multidrug-resistant infection, because current antibiotics fail against those pathogens. “That’s like winning the battle to lose the war.”

By investigating the microbiome, “we wanted to see if we could identify antimicrobial peptides that might spare key members of our regular microbiome, so that we wouldn’t totally disrupt the microbiome the way we do when we use broad-spectrum, small molecule–based antibiotics,” Dr. Bhatt said.

The researchers used artificial intelligence to sift through 400,000 proteins to predict, based on known antibiotics, which peptide sequences might have antimicrobial properties. From the results, they chose 78 peptides to synthesize and test.

“The application of computational approaches combined with experimental validation is very powerful and exciting,” said Jennifer Geddes-McAlister, PhD, professor of cell biology at the University of Guelph in Ontario, Canada, who was not involved in the study. “The study is robust in its approach to microbiome sampling.” 
 

The Long Journey from Lab to Clinic

More than half of the peptides the team tested effectively inhibited the growth of harmful bacteria, and prevotellin-2 (derived from the bacteria Prevotella copri)stood out as the most powerful.

“The study validates experimental data from the lab using animal models, which moves discoveries closer to the clinic,” said Dr. Geddes-McAlister. “Further testing with clinical trials is needed, but the potential for clinical application is promising.” 

Unfortunately, that’s not likely to happen anytime soon, said Dr. de la Fuente. “There is not enough economic incentive” for companies to develop new antibiotics. Ten years is his most hopeful guess for when we might see prevotellin-2, or a similar antibiotic, complete clinical trials.

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

Preexposure prophylaxis prescription reversals and abandonments were lower for patients seen by primary care clinicians than by other non–infectious disease clinicians, based on data from approximately 37,000 individuals.

Although preexposure prophylaxis (PrEP) has been associated with a reduced risk of HIV (human immunodeficiency virus) infection when used as prescribed, the association between PrEP prescription pickup and specialty of the prescribing clinician has not been examined, wrote Lorraine T. Dean, ScD, an epidemiologist at Johns Hopkins University, Baltimore, Maryland, and colleagues.

“HIV PrEP is highly effective at preventing new HIV cases, and while use is on the rise, is still used much less than it should be by people who are at risk of HIV,” Dr. Dean said in an interview. “This study is helpful in pinpointing who is at risk for not picking up PrEP and in helping us think through how to reach them so that they can be better positioned to get PrEP,” she said.

In a study published in JAMA Internal Medicine, the researchers reviewed data for PrEP care. The study population included 37,003 patients aged 18 years and older who received new insurer-approved PrEP prescriptions between 2015 and 2019. Most of the patients (77%) ranged in age from 25 to 64 years; 88% were male.

Pharmacy claims data were matched with clinician data from the US National Plan and Provider Enumeration System.

Clinicians were divided into three groups: primary care providers (PCPs), infectious disease specialists (IDs), and other specialists (defined as any clinician prescribing PrEP but not classified as a PCP or an ID specialist). The main binary outcomes were prescription reversal (defined as when a patient failed to retrieve a prescription) and abandonment (defined as when a patient neglected to pick up a prescription for 1 year).

Overall, of 24,604 patients 67% received prescriptions from PCPs, 3,571 (10%) received prescriptions from ID specialists, and 8828 (24%) received prescriptions from other specialty clinicians.

The prevalence of reversals for patients seen by PCPs, ID specialists, and other specialty clinicians was 18%, 18%, and 25%, respectively. The prevalence of abandonments by clinician group was 12%, 12%, and 20%, respectively.

In a regression analysis, patients prescribed PrEP by ID specialists had 10% lower odds of reversals and 12% lower odds of abandonments compared to those seen by PCPs (odds ratio 0.90 and 0.88, respectively). However, patients seen by other clinicians (not primary care or ID) were 33% and 54% more likely to have reversals and abandonments, respectively, compared with those seen by PCPs.

Many patients at risk for HIV first see a PCP and then are referred to a specialist, such as an ID physician, Dr. Dean said. “The patients who take the time to then follow up with a specialist may be most motivated and able to follow through with the specialist’s request, in this case, accessing their PrEP prescription,” she said. In the current study, the researchers were most surprised by how many other specialty providers are involved in PrEP care, which is very positive given the effectiveness of the medication, she noted.

“Our results suggest that a wide range of prescribers, regardless of specialty, should be equipped to prescribe PrEP as well as offer PrEP counseling,” Dr. Dean said. A key takeaway for clinicians is that PrEP should have no cost for the majority of patients in the United States, she emphasized. The absence of cost expands the population who should be interested and able to access PrEP, she said. Therefore, providers should be prepared to recommend PrEP to eligible patients, and seek training or continuing medical education for themselves so they feel equipped to prescribe and counsel patients on PrEP, she said.

“One limitation of this work is that, while it can point to what is happening, it cannot tell us why the reversals are happening; what is the reason patients prescribed by certain providers are more or less likely to get their PrEP,” Dr. Dean explained. “We have tried to do interviews with patients to understand why this might be happening, but it’s hard to find people who aren’t showing up to do something, compared to finding people who are showing up to do something,” she said. Alternatively, researchers could interview providers to understand their perspective on why differences in prescription pickups occur across specialties, she said.

Looking ahead, “a national PrEP program that includes elements of required clinician training could be beneficial, and research on how a national PrEP program could be implemented and impact HIV rates would be helpful in considering this strategy of prevention,” said Dr. Dean. 
 

Support All Prescribers to Increase PrEP Adherence

Differences in uptake of PrEP prescriptions may be explained by the different populations seen by various specialties, Meredith Green, MD, of Indiana University School of Medicine, Indianapolis, and Lona Mody, MD, of the University of Michigan, Ann Arbor, wrote in an accompanying editorial. However, the key question is how to support all prescribers and promote initiation and adherence to PrEP, they said.

Considerations include whether people at risk for HIV prefer to discuss PrEP with a clinician they already know, vs. a new specialist, but many PCPs are not familiar with the latest PrEP guidelines, they said.

“Interventions that support PrEP provision by PCPs, especially since they prescribed the largest proportion of PrEP prescriptions, can accelerate the uptake of PrEP,” the editorialists wrote.

“Supporting a diverse clinician workforce reflective of communities most impacted by HIV will remain critical, as will acknowledging and addressing HIV stigma,” they said. Educational interventions, including online programs and specialist access for complex cases, would help as well, they said. The approval of additional PrEP agents since the current study was conducted make it even more important to support PrEP prescribers and promote treatment adherence for those at risk for HIV, Dr. Green and Dr. Mody emphasized.

The study was funded by the National Institutes of Health. Dr. Dean had no financial conflicts to disclose. Dr. Green disclosed grants from Gilead and royalties from Wolters Kluwer unrelated to the current study; she also disclosed serving on the Centers for Disease Control and Prevention/Health Resources and Services Administration advisory committee on HIV, viral hepatitis, and sexually transmitted infection prevention and treatment. Dr. Mody disclosed grants from the US National Institute on Aging, Veterans Affairs, Centers for Disease Control and Prevention, NanoVibronix, and UpToDate unrelated to the current study.

Preexposure prophylaxis prescription reversals and abandonments were lower for patients seen by primary care clinicians than by other non–infectious disease clinicians, based on data from approximately 37,000 individuals.

Although preexposure prophylaxis (PrEP) has been associated with a reduced risk of HIV (human immunodeficiency virus) infection when used as prescribed, the association between PrEP prescription pickup and specialty of the prescribing clinician has not been examined, wrote Lorraine T. Dean, ScD, an epidemiologist at Johns Hopkins University, Baltimore, Maryland, and colleagues.

“HIV PrEP is highly effective at preventing new HIV cases, and while use is on the rise, is still used much less than it should be by people who are at risk of HIV,” Dr. Dean said in an interview. “This study is helpful in pinpointing who is at risk for not picking up PrEP and in helping us think through how to reach them so that they can be better positioned to get PrEP,” she said.

In a study published in JAMA Internal Medicine, the researchers reviewed data for PrEP care. The study population included 37,003 patients aged 18 years and older who received new insurer-approved PrEP prescriptions between 2015 and 2019. Most of the patients (77%) ranged in age from 25 to 64 years; 88% were male.

Pharmacy claims data were matched with clinician data from the US National Plan and Provider Enumeration System.

Clinicians were divided into three groups: primary care providers (PCPs), infectious disease specialists (IDs), and other specialists (defined as any clinician prescribing PrEP but not classified as a PCP or an ID specialist). The main binary outcomes were prescription reversal (defined as when a patient failed to retrieve a prescription) and abandonment (defined as when a patient neglected to pick up a prescription for 1 year).

Overall, of 24,604 patients 67% received prescriptions from PCPs, 3,571 (10%) received prescriptions from ID specialists, and 8828 (24%) received prescriptions from other specialty clinicians.

The prevalence of reversals for patients seen by PCPs, ID specialists, and other specialty clinicians was 18%, 18%, and 25%, respectively. The prevalence of abandonments by clinician group was 12%, 12%, and 20%, respectively.

In a regression analysis, patients prescribed PrEP by ID specialists had 10% lower odds of reversals and 12% lower odds of abandonments compared to those seen by PCPs (odds ratio 0.90 and 0.88, respectively). However, patients seen by other clinicians (not primary care or ID) were 33% and 54% more likely to have reversals and abandonments, respectively, compared with those seen by PCPs.

Many patients at risk for HIV first see a PCP and then are referred to a specialist, such as an ID physician, Dr. Dean said. “The patients who take the time to then follow up with a specialist may be most motivated and able to follow through with the specialist’s request, in this case, accessing their PrEP prescription,” she said. In the current study, the researchers were most surprised by how many other specialty providers are involved in PrEP care, which is very positive given the effectiveness of the medication, she noted.

“Our results suggest that a wide range of prescribers, regardless of specialty, should be equipped to prescribe PrEP as well as offer PrEP counseling,” Dr. Dean said. A key takeaway for clinicians is that PrEP should have no cost for the majority of patients in the United States, she emphasized. The absence of cost expands the population who should be interested and able to access PrEP, she said. Therefore, providers should be prepared to recommend PrEP to eligible patients, and seek training or continuing medical education for themselves so they feel equipped to prescribe and counsel patients on PrEP, she said.

“One limitation of this work is that, while it can point to what is happening, it cannot tell us why the reversals are happening; what is the reason patients prescribed by certain providers are more or less likely to get their PrEP,” Dr. Dean explained. “We have tried to do interviews with patients to understand why this might be happening, but it’s hard to find people who aren’t showing up to do something, compared to finding people who are showing up to do something,” she said. Alternatively, researchers could interview providers to understand their perspective on why differences in prescription pickups occur across specialties, she said.

Looking ahead, “a national PrEP program that includes elements of required clinician training could be beneficial, and research on how a national PrEP program could be implemented and impact HIV rates would be helpful in considering this strategy of prevention,” said Dr. Dean. 
 

Support All Prescribers to Increase PrEP Adherence

Differences in uptake of PrEP prescriptions may be explained by the different populations seen by various specialties, Meredith Green, MD, of Indiana University School of Medicine, Indianapolis, and Lona Mody, MD, of the University of Michigan, Ann Arbor, wrote in an accompanying editorial. However, the key question is how to support all prescribers and promote initiation and adherence to PrEP, they said.

Considerations include whether people at risk for HIV prefer to discuss PrEP with a clinician they already know, vs. a new specialist, but many PCPs are not familiar with the latest PrEP guidelines, they said.

“Interventions that support PrEP provision by PCPs, especially since they prescribed the largest proportion of PrEP prescriptions, can accelerate the uptake of PrEP,” the editorialists wrote.

“Supporting a diverse clinician workforce reflective of communities most impacted by HIV will remain critical, as will acknowledging and addressing HIV stigma,” they said. Educational interventions, including online programs and specialist access for complex cases, would help as well, they said. The approval of additional PrEP agents since the current study was conducted make it even more important to support PrEP prescribers and promote treatment adherence for those at risk for HIV, Dr. Green and Dr. Mody emphasized.

The study was funded by the National Institutes of Health. Dr. Dean had no financial conflicts to disclose. Dr. Green disclosed grants from Gilead and royalties from Wolters Kluwer unrelated to the current study; she also disclosed serving on the Centers for Disease Control and Prevention/Health Resources and Services Administration advisory committee on HIV, viral hepatitis, and sexually transmitted infection prevention and treatment. Dr. Mody disclosed grants from the US National Institute on Aging, Veterans Affairs, Centers for Disease Control and Prevention, NanoVibronix, and UpToDate unrelated to the current study.

Preexposure prophylaxis prescription reversals and abandonments were lower for patients seen by primary care clinicians than by other non–infectious disease clinicians, based on data from approximately 37,000 individuals.

Although preexposure prophylaxis (PrEP) has been associated with a reduced risk of HIV (human immunodeficiency virus) infection when used as prescribed, the association between PrEP prescription pickup and specialty of the prescribing clinician has not been examined, wrote Lorraine T. Dean, ScD, an epidemiologist at Johns Hopkins University, Baltimore, Maryland, and colleagues.

“HIV PrEP is highly effective at preventing new HIV cases, and while use is on the rise, is still used much less than it should be by people who are at risk of HIV,” Dr. Dean said in an interview. “This study is helpful in pinpointing who is at risk for not picking up PrEP and in helping us think through how to reach them so that they can be better positioned to get PrEP,” she said.

In a study published in JAMA Internal Medicine, the researchers reviewed data for PrEP care. The study population included 37,003 patients aged 18 years and older who received new insurer-approved PrEP prescriptions between 2015 and 2019. Most of the patients (77%) ranged in age from 25 to 64 years; 88% were male.

Pharmacy claims data were matched with clinician data from the US National Plan and Provider Enumeration System.

Clinicians were divided into three groups: primary care providers (PCPs), infectious disease specialists (IDs), and other specialists (defined as any clinician prescribing PrEP but not classified as a PCP or an ID specialist). The main binary outcomes were prescription reversal (defined as when a patient failed to retrieve a prescription) and abandonment (defined as when a patient neglected to pick up a prescription for 1 year).

Overall, of 24,604 patients 67% received prescriptions from PCPs, 3,571 (10%) received prescriptions from ID specialists, and 8828 (24%) received prescriptions from other specialty clinicians.

The prevalence of reversals for patients seen by PCPs, ID specialists, and other specialty clinicians was 18%, 18%, and 25%, respectively. The prevalence of abandonments by clinician group was 12%, 12%, and 20%, respectively.

In a regression analysis, patients prescribed PrEP by ID specialists had 10% lower odds of reversals and 12% lower odds of abandonments compared to those seen by PCPs (odds ratio 0.90 and 0.88, respectively). However, patients seen by other clinicians (not primary care or ID) were 33% and 54% more likely to have reversals and abandonments, respectively, compared with those seen by PCPs.

Many patients at risk for HIV first see a PCP and then are referred to a specialist, such as an ID physician, Dr. Dean said. “The patients who take the time to then follow up with a specialist may be most motivated and able to follow through with the specialist’s request, in this case, accessing their PrEP prescription,” she said. In the current study, the researchers were most surprised by how many other specialty providers are involved in PrEP care, which is very positive given the effectiveness of the medication, she noted.

“Our results suggest that a wide range of prescribers, regardless of specialty, should be equipped to prescribe PrEP as well as offer PrEP counseling,” Dr. Dean said. A key takeaway for clinicians is that PrEP should have no cost for the majority of patients in the United States, she emphasized. The absence of cost expands the population who should be interested and able to access PrEP, she said. Therefore, providers should be prepared to recommend PrEP to eligible patients, and seek training or continuing medical education for themselves so they feel equipped to prescribe and counsel patients on PrEP, she said.

“One limitation of this work is that, while it can point to what is happening, it cannot tell us why the reversals are happening; what is the reason patients prescribed by certain providers are more or less likely to get their PrEP,” Dr. Dean explained. “We have tried to do interviews with patients to understand why this might be happening, but it’s hard to find people who aren’t showing up to do something, compared to finding people who are showing up to do something,” she said. Alternatively, researchers could interview providers to understand their perspective on why differences in prescription pickups occur across specialties, she said.

Looking ahead, “a national PrEP program that includes elements of required clinician training could be beneficial, and research on how a national PrEP program could be implemented and impact HIV rates would be helpful in considering this strategy of prevention,” said Dr. Dean. 
 

Support All Prescribers to Increase PrEP Adherence

Differences in uptake of PrEP prescriptions may be explained by the different populations seen by various specialties, Meredith Green, MD, of Indiana University School of Medicine, Indianapolis, and Lona Mody, MD, of the University of Michigan, Ann Arbor, wrote in an accompanying editorial. However, the key question is how to support all prescribers and promote initiation and adherence to PrEP, they said.

Considerations include whether people at risk for HIV prefer to discuss PrEP with a clinician they already know, vs. a new specialist, but many PCPs are not familiar with the latest PrEP guidelines, they said.

“Interventions that support PrEP provision by PCPs, especially since they prescribed the largest proportion of PrEP prescriptions, can accelerate the uptake of PrEP,” the editorialists wrote.

“Supporting a diverse clinician workforce reflective of communities most impacted by HIV will remain critical, as will acknowledging and addressing HIV stigma,” they said. Educational interventions, including online programs and specialist access for complex cases, would help as well, they said. The approval of additional PrEP agents since the current study was conducted make it even more important to support PrEP prescribers and promote treatment adherence for those at risk for HIV, Dr. Green and Dr. Mody emphasized.

The study was funded by the National Institutes of Health. Dr. Dean had no financial conflicts to disclose. Dr. Green disclosed grants from Gilead and royalties from Wolters Kluwer unrelated to the current study; she also disclosed serving on the Centers for Disease Control and Prevention/Health Resources and Services Administration advisory committee on HIV, viral hepatitis, and sexually transmitted infection prevention and treatment. Dr. Mody disclosed grants from the US National Institute on Aging, Veterans Affairs, Centers for Disease Control and Prevention, NanoVibronix, and UpToDate unrelated to the current study.

This transcript has been edited for clarity.

I would like to briefly discuss what I consider to be a very discouraging report and one that I believe we as an oncology society and, quite frankly, as a medical community need to deal with. 

The manuscript I’m referring to is from the United States Department of Health and Human Services, titled, “Human Papillomavirus Vaccination Coverage in Children Ages 9-17 Years: United States, 2022.” This particular analysis looked at the coverage of both men and women — young boys and young girls, I would say — receiving at least one dose of the recommended human papillomavirus (HPV) vaccination. 

Since 2006, girls have been recommended to receive HPV vaccination; for boys, it’s been since 2011. Certainly, the time period that we’re considering falls within the recommendations based on overwhelmingly positive data. Now, today, still, the recommendation is for more than one vaccine. Obviously, there may be evidence in the future that a single vaccination may be acceptable or appropriate. But today, it’s more than one. 

In this particular analysis, they were looking at just a single vaccination. The vaccines have targeted young individuals, both male and female children aged 11-12 years, but it’s certainly acceptable to look starting at age 9. 

What is the bottom line? At least one dose of the HPV vaccination was given to 38.6% of children aged 9-17 years in 2022. We are talking about a cancer-preventive vaccine, which on the basis of population-based data in the United States, but also in other countries, is incredibly effective in preventing HPV-associated cancers. This not only includes cervical cancer, but also a large percentage of head and neck cancers.

For this vaccine, which is incredibly safe and incredibly effective, in this country, only 38.6% have received even a single dose. It is noted that the individuals with private insurance had a higher rate, at 41.5%, than individuals with no insurance, at only 20.7%. 

In my opinion, this is clearly a failure of our public health establishment at all levels. My own focus has been in gynecologic cancers. I’ve seen young women with advanced cervical cancer, and this is a disease we can prevent. Yet, this is where we are. 

For those of you who are interested in cancer prevention or public health, I think this is a very sobering statistic. It’s my plea and my hope that we can, as a society, somehow do something about it. 

I thank you for listening. I would encourage you to think about this question if you’re in this area.
 

Dr. Markman, professor, Department of Medical Oncology and Therapeutics Research, City of Hope, Duarte, California, and president of Medicine & Science, City of Hope Atlanta, Chicago, and Phoenix, disclosed ties with GlaxoSmithKline and AstraZeneca.

A version of this article appeared on Medscape.com.

This transcript has been edited for clarity.

I would like to briefly discuss what I consider to be a very discouraging report and one that I believe we as an oncology society and, quite frankly, as a medical community need to deal with. 

The manuscript I’m referring to is from the United States Department of Health and Human Services, titled, “Human Papillomavirus Vaccination Coverage in Children Ages 9-17 Years: United States, 2022.” This particular analysis looked at the coverage of both men and women — young boys and young girls, I would say — receiving at least one dose of the recommended human papillomavirus (HPV) vaccination. 

Since 2006, girls have been recommended to receive HPV vaccination; for boys, it’s been since 2011. Certainly, the time period that we’re considering falls within the recommendations based on overwhelmingly positive data. Now, today, still, the recommendation is for more than one vaccine. Obviously, there may be evidence in the future that a single vaccination may be acceptable or appropriate. But today, it’s more than one. 

In this particular analysis, they were looking at just a single vaccination. The vaccines have targeted young individuals, both male and female children aged 11-12 years, but it’s certainly acceptable to look starting at age 9. 

What is the bottom line? At least one dose of the HPV vaccination was given to 38.6% of children aged 9-17 years in 2022. We are talking about a cancer-preventive vaccine, which on the basis of population-based data in the United States, but also in other countries, is incredibly effective in preventing HPV-associated cancers. This not only includes cervical cancer, but also a large percentage of head and neck cancers.

For this vaccine, which is incredibly safe and incredibly effective, in this country, only 38.6% have received even a single dose. It is noted that the individuals with private insurance had a higher rate, at 41.5%, than individuals with no insurance, at only 20.7%. 

In my opinion, this is clearly a failure of our public health establishment at all levels. My own focus has been in gynecologic cancers. I’ve seen young women with advanced cervical cancer, and this is a disease we can prevent. Yet, this is where we are. 

For those of you who are interested in cancer prevention or public health, I think this is a very sobering statistic. It’s my plea and my hope that we can, as a society, somehow do something about it. 

I thank you for listening. I would encourage you to think about this question if you’re in this area.
 

Dr. Markman, professor, Department of Medical Oncology and Therapeutics Research, City of Hope, Duarte, California, and president of Medicine & Science, City of Hope Atlanta, Chicago, and Phoenix, disclosed ties with GlaxoSmithKline and AstraZeneca.

A version of this article appeared on Medscape.com.

This transcript has been edited for clarity.

I would like to briefly discuss what I consider to be a very discouraging report and one that I believe we as an oncology society and, quite frankly, as a medical community need to deal with. 

The manuscript I’m referring to is from the United States Department of Health and Human Services, titled, “Human Papillomavirus Vaccination Coverage in Children Ages 9-17 Years: United States, 2022.” This particular analysis looked at the coverage of both men and women — young boys and young girls, I would say — receiving at least one dose of the recommended human papillomavirus (HPV) vaccination. 

Since 2006, girls have been recommended to receive HPV vaccination; for boys, it’s been since 2011. Certainly, the time period that we’re considering falls within the recommendations based on overwhelmingly positive data. Now, today, still, the recommendation is for more than one vaccine. Obviously, there may be evidence in the future that a single vaccination may be acceptable or appropriate. But today, it’s more than one. 

In this particular analysis, they were looking at just a single vaccination. The vaccines have targeted young individuals, both male and female children aged 11-12 years, but it’s certainly acceptable to look starting at age 9. 

What is the bottom line? At least one dose of the HPV vaccination was given to 38.6% of children aged 9-17 years in 2022. We are talking about a cancer-preventive vaccine, which on the basis of population-based data in the United States, but also in other countries, is incredibly effective in preventing HPV-associated cancers. This not only includes cervical cancer, but also a large percentage of head and neck cancers.

For this vaccine, which is incredibly safe and incredibly effective, in this country, only 38.6% have received even a single dose. It is noted that the individuals with private insurance had a higher rate, at 41.5%, than individuals with no insurance, at only 20.7%. 

In my opinion, this is clearly a failure of our public health establishment at all levels. My own focus has been in gynecologic cancers. I’ve seen young women with advanced cervical cancer, and this is a disease we can prevent. Yet, this is where we are. 

For those of you who are interested in cancer prevention or public health, I think this is a very sobering statistic. It’s my plea and my hope that we can, as a society, somehow do something about it. 

I thank you for listening. I would encourage you to think about this question if you’re in this area.
 

Dr. Markman, professor, Department of Medical Oncology and Therapeutics Research, City of Hope, Duarte, California, and president of Medicine & Science, City of Hope Atlanta, Chicago, and Phoenix, disclosed ties with GlaxoSmithKline and AstraZeneca.

A version of this article appeared on Medscape.com.

RSV, influenza, and now SARS-CoV2 drive annual winter respiratory surges. For children younger than 5 years old, RSV is the main drive — approximately 2,000,000 outpatient/ED visits and about 75,000 hospitalizations annually. RSV disease ranges from upper respiratory tract infections, eg, in older children and healthy adults, to more severe lower tract disease in young children and the elderly. Premature infants and high-risk groups are particularly prone to severe disease.¹ Up to 300 pediatric RSV deaths occur yearly. “Normal” RSV seasons start in mid-November, peak in late December-January, and end after April. Note: More drawn out seasons occur in southern latitudes, eg Texas or Florida. But lately RSV seasons have been anything but normal.

2015-2016 to 2022-2023

RSV data from the Pediatric Health Information System (PHIS), collected at over 49 US children’s hospitals during 2015 to early 2023, show how crazy RSV seasons have been lately.² The involved months, intensity, and duration of four prepandemic seasons were pretty “normal” (Figure 1). The 2019-2020 season started normally, peaked in January 2020, and was slowing as expected by February. But when SARS-Cov-2 restrictions kicked in during mid-March, RSV detections tanked to almost nothing (ditto other respiratory viruses). A near 14-month RSV hiatus meant that the 2020-2021 RSV season never materialized. However, RSV was not done with us in 2021. It rebounded in May with weekly hospitalizations peaking in late July; this “rebound season” lasted 9 months, not dropping to baseline until February 2022 (Figure 1).

I guess we should have expected a post-pandemic “disturbance in the Force,” as Yoda once said; but I sure didn’t see a prolonged summer/fall/early winter RSV season coming. It was like two “normal” seasons mashed up into one late-but-long season. Not to be outdone, the 2022-2023 RSV season started early (September) and hospitalizations skyrocketed to peak in November at over twice the peak number from any year since 2015, overloading hospitals (influenza and SARS-Cov-2 seasons were co-circulating). The season terminated early though (March 2023).

Okay, so RSV seasonality/intensity were weird post pandemic, but was anything else different? Some 2021-2023 data suggest more RSV disease in older children, rather than the usual younger than 18 month-olds going through their first winter.³ More medically attended RSV in older ages (2-4 years of life) may have been due to the pandemic year without RSV circulation distorting herd immunity, ie older children remained RSV naive. Other data suggest the apparent increase was really just more frequent multiplex viral testing in older children triggered by SARS-CoV-2 co-circulation.⁴ More data are needed to decide.
 

CDC 2023-2024 RESP-NET data

The 2023-2024 winter surge (Figure 2), as measured by RESP-NET’s cumulative RSV,influenza and SARS-CoV-2 hospitalization rates for 0- to 5-year-olds,⁵ shows that all three viruses’ seasonal months were normal-ish: late October 2023 start, late December-early January peak, and mid-May 2024 return to baseline. RSV season was approximately 22% less severe by area-under-the-curve calculations compared with 2022-2023, but still worse than prepandemic years.⁶

One wonders if the 2022-2023 RSV season might have been worse but for use of the limited supply of nirsevimab.⁷

Viral Parade

Now we ready ourselves for the 2024-2025 respiratory surge, wondering what nature has in store for us. Will the usual “respiratory virus parade” occur? Will rhinovirus and parainfluenza prevalence bump after a few weeks of schools being in session, adding to the now-usual summer/fall SARS-CoV-2 surge? Note: Twenty-seven states as of Aug. 16 had high SARS-CoV-2 detection in wastewater. Will RSV and influenza start sometime in October/November, peak in January (along with rising SARS-CoV2 activity), followed by a second parainfluenza bump as SARS-CoV-2, influenza, and RSV drop off in April/May? Further, will RSV and influenza seasons be more or less severe than the last 2 years?

Prediction

The overall 2024-2025 respiratory season will be less severe than the past 2 years and hopefully than recent prepandemic years. What is the blueprint for a milder season? First, herd immunity to non-RSV and non-influenza viruses (parainfluenza, rhinovirus, metapneumovirus, adenovirus) in older children should be normalized after 2 years back to usual social activity. So, I expect no mega-seasons from them. The emerging SARS-CoV-2 virus (LB.1) is immunologically close to its recent still-circulating ancestors (KP.2, KP.2.3, KP.³ and KP.3.1.1), so existing SARS-CoV2 herd immunity along with recommended booster vaccine uptake should keep the lid on SARS-CoV2.

Influenza Could Be the Bad News

Which type will dominate? Will a drift/shift occur or vaccine-mismatch reduce vaccine effectiveness? Can we get at least half the population influenza vaccinated, given the vaccine fatigue permeating the US population? The influenza season now underway in the Southern Hemisphere usually helps us predict our season. The Australian May-August 2024 experience (still on an upward trajectory for severity in mid-August) saw no drift/shift or vaccine mismatch. However, this 2024 season has been as severe as 2022 (their worst in a decade). That said, more than 95% has been type A (mostly H1N1 but H3N2 increased in July). So, if our overall 2024-2025 respiratory season is not milder, influenza is the most likely culprit. To reduce chances of influenza being the fly-in-the-ointment, we need to be particularly proactive with seasonal influenza vaccine which is back to the traditional trivalent formulation (one H1N1, one H3N2, and one B type).⁸ All of this could go out the window if avian influenza becomes more transmissible, but that seems unlikely at present.

Mild RSV Season?

RSV season should be blunted because of the increased use of both the remarkably effective CDC-recommended maternal RSV vaccine⁹ (one dose during pregnancy weeks 32 through 36, administered September through January) and of nirsevimab (up to 90% reduction in hospitalizations and ED visits).¹⁰ (See Figure 3.)

I also expect residual disease to occur mostly in younger than 18 month-olds (the “normal” aged population experiencing their first winter), who received no passive immunity (mother RSV unvaccinated and child did not receive nirsevimab). Some disease will still occur in high-risk infants/children. However, unlike active vaccination strategies, a competent immune system is not required to benefit from passive antibody, whether transplacental or directly administered.
 

Deep Thought

What if the traditional RSV seasonal hospitalization surge fails to materialize this season? It could happen. If we could get high acceptance/uptake of maternal vaccine and infant nirsevimab, RSV season could resemble the dramatic drop in rotavirus disease the second year after rotavirus vaccine introduction. We could be asking ourselves — “What happened to RSV?”

Dr. Harrison is professor of pediatrics and pediatric infectious diseases at Children’s Mercy Hospitals and Clinics, Kansas City, Missouri. He said he had no relevant financial disclosures. Email him at [email protected].

References

1. CDC. RSV in Infants and Young Children. Respiratory Syncytial Virus Infection (RSV). June 18, 2024. https://www.cdc.gov/rsv/infants-young-children/index.html.

2. Suss RJ and Simões EAF. Respiratory Syncytial Virus Hospital-Based Burden of Disease in Children Younger Than 5 Respiratory Syncytial Virus Hospital-Based Burden of Disease in Children Younger Than 5 Years, 2015-2022. JAMA Netw Open. 2024;7(4):e247125. doi:10.1001/jamanetworkopen.2024.7125.

3. Winthrop ZA et al. Pediatric Respiratory Syncytial Virus Hospitalizations and Respiratory Support After the COVID-19 Pandemic. JAMA Netw Open. 2024;7(6):e2416852. doi:10.1001/jamanetworkopen.2024.16852.

4. Petros BA et al. Increased Pediatric RSV Case Counts Following the Emergence of SARS-CoV-2 Are Attributable to Increased Testing. medRxiv [Preprint]. 2024 Feb 12:2024.02.06.24302387. doi: 10.1101/2024.02.06.24302387.

5. Rates of Laboratory-Confirmed RSV, COVID-19, and Flu Hospitalizations from the RESP-NET Surveillance Systems. Centers for Disease Control and Prevention. https://data.cdc.gov/Public-Health-Surveillance/Rates-of-Laboratory-Confirmed-RSV-COVID-19-and-Flu/kvib-3txy/about_data.

6. CDC. Evaluating the 2023-2024 Respiratory Disease Season Outlook. CFA: Qualitative Assessments. August 14, 2024. https://www.cdc.gov/cfa-qualitative-assessments/php/data-research/2023-2024-season-outlook-retro.html.

7. Health Alert Network (HAN). Limited Availability of Nirsevimab in the United States—Interim CDC Recommendations to Protect Infants from Respiratory Syncytial Virus (RSV) during the 2023–2024 Respiratory Virus Season. October 23, 2023. https://emergency.cdc.gov/han/2023/han00499.asp.

8. CDC. Information for the 2024-2025 Flu Season. Centers for Disease Control and Prevention. March 14, 2024. https://www.cdc.gov/flu/season/faq-flu-season-2024-2025.htm.

9. Kampmann B et al. Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants. N Engl J Med. 2023 Apr 20;388(16):1451-1464. doi: 10.1056/NEJMoa2216480.

10. Moline HL. Early Estimate of Nirsevimab Effectiveness for Prevention of Respiratory Syncytial Virus–Associated Hospitalization Among Infants Entering Their First Respiratory Syncytial Virus Season — New Vaccine Surveillance Network, October 2023–February 2024. MMWR Morb Mortal Wkly Rep. 2024;73. doi: 10.15585/mmwr.mm7309a4.

RSV, influenza, and now SARS-CoV2 drive annual winter respiratory surges. For children younger than 5 years old, RSV is the main drive — approximately 2,000,000 outpatient/ED visits and about 75,000 hospitalizations annually. RSV disease ranges from upper respiratory tract infections, eg, in older children and healthy adults, to more severe lower tract disease in young children and the elderly. Premature infants and high-risk groups are particularly prone to severe disease.¹ Up to 300 pediatric RSV deaths occur yearly. “Normal” RSV seasons start in mid-November, peak in late December-January, and end after April. Note: More drawn out seasons occur in southern latitudes, eg Texas or Florida. But lately RSV seasons have been anything but normal.

2015-2016 to 2022-2023

RSV data from the Pediatric Health Information System (PHIS), collected at over 49 US children’s hospitals during 2015 to early 2023, show how crazy RSV seasons have been lately.² The involved months, intensity, and duration of four prepandemic seasons were pretty “normal” (Figure 1). The 2019-2020 season started normally, peaked in January 2020, and was slowing as expected by February. But when SARS-Cov-2 restrictions kicked in during mid-March, RSV detections tanked to almost nothing (ditto other respiratory viruses). A near 14-month RSV hiatus meant that the 2020-2021 RSV season never materialized. However, RSV was not done with us in 2021. It rebounded in May with weekly hospitalizations peaking in late July; this “rebound season” lasted 9 months, not dropping to baseline until February 2022 (Figure 1).

I guess we should have expected a post-pandemic “disturbance in the Force,” as Yoda once said; but I sure didn’t see a prolonged summer/fall/early winter RSV season coming. It was like two “normal” seasons mashed up into one late-but-long season. Not to be outdone, the 2022-2023 RSV season started early (September) and hospitalizations skyrocketed to peak in November at over twice the peak number from any year since 2015, overloading hospitals (influenza and SARS-Cov-2 seasons were co-circulating). The season terminated early though (March 2023).

Okay, so RSV seasonality/intensity were weird post pandemic, but was anything else different? Some 2021-2023 data suggest more RSV disease in older children, rather than the usual younger than 18 month-olds going through their first winter.³ More medically attended RSV in older ages (2-4 years of life) may have been due to the pandemic year without RSV circulation distorting herd immunity, ie older children remained RSV naive. Other data suggest the apparent increase was really just more frequent multiplex viral testing in older children triggered by SARS-CoV-2 co-circulation.⁴ More data are needed to decide.
 

CDC 2023-2024 RESP-NET data

The 2023-2024 winter surge (Figure 2), as measured by RESP-NET’s cumulative RSV,influenza and SARS-CoV-2 hospitalization rates for 0- to 5-year-olds,⁵ shows that all three viruses’ seasonal months were normal-ish: late October 2023 start, late December-early January peak, and mid-May 2024 return to baseline. RSV season was approximately 22% less severe by area-under-the-curve calculations compared with 2022-2023, but still worse than prepandemic years.⁶

One wonders if the 2022-2023 RSV season might have been worse but for use of the limited supply of nirsevimab.⁷

Viral Parade

Now we ready ourselves for the 2024-2025 respiratory surge, wondering what nature has in store for us. Will the usual “respiratory virus parade” occur? Will rhinovirus and parainfluenza prevalence bump after a few weeks of schools being in session, adding to the now-usual summer/fall SARS-CoV-2 surge? Note: Twenty-seven states as of Aug. 16 had high SARS-CoV-2 detection in wastewater. Will RSV and influenza start sometime in October/November, peak in January (along with rising SARS-CoV2 activity), followed by a second parainfluenza bump as SARS-CoV-2, influenza, and RSV drop off in April/May? Further, will RSV and influenza seasons be more or less severe than the last 2 years?

Prediction

The overall 2024-2025 respiratory season will be less severe than the past 2 years and hopefully than recent prepandemic years. What is the blueprint for a milder season? First, herd immunity to non-RSV and non-influenza viruses (parainfluenza, rhinovirus, metapneumovirus, adenovirus) in older children should be normalized after 2 years back to usual social activity. So, I expect no mega-seasons from them. The emerging SARS-CoV-2 virus (LB.1) is immunologically close to its recent still-circulating ancestors (KP.2, KP.2.3, KP.³ and KP.3.1.1), so existing SARS-CoV2 herd immunity along with recommended booster vaccine uptake should keep the lid on SARS-CoV2.

Influenza Could Be the Bad News

Which type will dominate? Will a drift/shift occur or vaccine-mismatch reduce vaccine effectiveness? Can we get at least half the population influenza vaccinated, given the vaccine fatigue permeating the US population? The influenza season now underway in the Southern Hemisphere usually helps us predict our season. The Australian May-August 2024 experience (still on an upward trajectory for severity in mid-August) saw no drift/shift or vaccine mismatch. However, this 2024 season has been as severe as 2022 (their worst in a decade). That said, more than 95% has been type A (mostly H1N1 but H3N2 increased in July). So, if our overall 2024-2025 respiratory season is not milder, influenza is the most likely culprit. To reduce chances of influenza being the fly-in-the-ointment, we need to be particularly proactive with seasonal influenza vaccine which is back to the traditional trivalent formulation (one H1N1, one H3N2, and one B type).⁸ All of this could go out the window if avian influenza becomes more transmissible, but that seems unlikely at present.

Mild RSV Season?

RSV season should be blunted because of the increased use of both the remarkably effective CDC-recommended maternal RSV vaccine⁹ (one dose during pregnancy weeks 32 through 36, administered September through January) and of nirsevimab (up to 90% reduction in hospitalizations and ED visits).¹⁰ (See Figure 3.)

I also expect residual disease to occur mostly in younger than 18 month-olds (the “normal” aged population experiencing their first winter), who received no passive immunity (mother RSV unvaccinated and child did not receive nirsevimab). Some disease will still occur in high-risk infants/children. However, unlike active vaccination strategies, a competent immune system is not required to benefit from passive antibody, whether transplacental or directly administered.
 

Deep Thought

What if the traditional RSV seasonal hospitalization surge fails to materialize this season? It could happen. If we could get high acceptance/uptake of maternal vaccine and infant nirsevimab, RSV season could resemble the dramatic drop in rotavirus disease the second year after rotavirus vaccine introduction. We could be asking ourselves — “What happened to RSV?”

Dr. Harrison is professor of pediatrics and pediatric infectious diseases at Children’s Mercy Hospitals and Clinics, Kansas City, Missouri. He said he had no relevant financial disclosures. Email him at [email protected].

References

1. CDC. RSV in Infants and Young Children. Respiratory Syncytial Virus Infection (RSV). June 18, 2024. https://www.cdc.gov/rsv/infants-young-children/index.html.

2. Suss RJ and Simões EAF. Respiratory Syncytial Virus Hospital-Based Burden of Disease in Children Younger Than 5 Respiratory Syncytial Virus Hospital-Based Burden of Disease in Children Younger Than 5 Years, 2015-2022. JAMA Netw Open. 2024;7(4):e247125. doi:10.1001/jamanetworkopen.2024.7125.

3. Winthrop ZA et al. Pediatric Respiratory Syncytial Virus Hospitalizations and Respiratory Support After the COVID-19 Pandemic. JAMA Netw Open. 2024;7(6):e2416852. doi:10.1001/jamanetworkopen.2024.16852.

4. Petros BA et al. Increased Pediatric RSV Case Counts Following the Emergence of SARS-CoV-2 Are Attributable to Increased Testing. medRxiv [Preprint]. 2024 Feb 12:2024.02.06.24302387. doi: 10.1101/2024.02.06.24302387.

5. Rates of Laboratory-Confirmed RSV, COVID-19, and Flu Hospitalizations from the RESP-NET Surveillance Systems. Centers for Disease Control and Prevention. https://data.cdc.gov/Public-Health-Surveillance/Rates-of-Laboratory-Confirmed-RSV-COVID-19-and-Flu/kvib-3txy/about_data.

6. CDC. Evaluating the 2023-2024 Respiratory Disease Season Outlook. CFA: Qualitative Assessments. August 14, 2024. https://www.cdc.gov/cfa-qualitative-assessments/php/data-research/2023-2024-season-outlook-retro.html.

7. Health Alert Network (HAN). Limited Availability of Nirsevimab in the United States—Interim CDC Recommendations to Protect Infants from Respiratory Syncytial Virus (RSV) during the 2023–2024 Respiratory Virus Season. October 23, 2023. https://emergency.cdc.gov/han/2023/han00499.asp.

8. CDC. Information for the 2024-2025 Flu Season. Centers for Disease Control and Prevention. March 14, 2024. https://www.cdc.gov/flu/season/faq-flu-season-2024-2025.htm.

9. Kampmann B et al. Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants. N Engl J Med. 2023 Apr 20;388(16):1451-1464. doi: 10.1056/NEJMoa2216480.

10. Moline HL. Early Estimate of Nirsevimab Effectiveness for Prevention of Respiratory Syncytial Virus–Associated Hospitalization Among Infants Entering Their First Respiratory Syncytial Virus Season — New Vaccine Surveillance Network, October 2023–February 2024. MMWR Morb Mortal Wkly Rep. 2024;73. doi: 10.15585/mmwr.mm7309a4.

RSV, influenza, and now SARS-CoV2 drive annual winter respiratory surges. For children younger than 5 years old, RSV is the main drive — approximately 2,000,000 outpatient/ED visits and about 75,000 hospitalizations annually. RSV disease ranges from upper respiratory tract infections, eg, in older children and healthy adults, to more severe lower tract disease in young children and the elderly. Premature infants and high-risk groups are particularly prone to severe disease.¹ Up to 300 pediatric RSV deaths occur yearly. “Normal” RSV seasons start in mid-November, peak in late December-January, and end after April. Note: More drawn out seasons occur in southern latitudes, eg Texas or Florida. But lately RSV seasons have been anything but normal.

2015-2016 to 2022-2023

RSV data from the Pediatric Health Information System (PHIS), collected at over 49 US children’s hospitals during 2015 to early 2023, show how crazy RSV seasons have been lately.² The involved months, intensity, and duration of four prepandemic seasons were pretty “normal” (Figure 1). The 2019-2020 season started normally, peaked in January 2020, and was slowing as expected by February. But when SARS-Cov-2 restrictions kicked in during mid-March, RSV detections tanked to almost nothing (ditto other respiratory viruses). A near 14-month RSV hiatus meant that the 2020-2021 RSV season never materialized. However, RSV was not done with us in 2021. It rebounded in May with weekly hospitalizations peaking in late July; this “rebound season” lasted 9 months, not dropping to baseline until February 2022 (Figure 1).

I guess we should have expected a post-pandemic “disturbance in the Force,” as Yoda once said; but I sure didn’t see a prolonged summer/fall/early winter RSV season coming. It was like two “normal” seasons mashed up into one late-but-long season. Not to be outdone, the 2022-2023 RSV season started early (September) and hospitalizations skyrocketed to peak in November at over twice the peak number from any year since 2015, overloading hospitals (influenza and SARS-Cov-2 seasons were co-circulating). The season terminated early though (March 2023).

Okay, so RSV seasonality/intensity were weird post pandemic, but was anything else different? Some 2021-2023 data suggest more RSV disease in older children, rather than the usual younger than 18 month-olds going through their first winter.³ More medically attended RSV in older ages (2-4 years of life) may have been due to the pandemic year without RSV circulation distorting herd immunity, ie older children remained RSV naive. Other data suggest the apparent increase was really just more frequent multiplex viral testing in older children triggered by SARS-CoV-2 co-circulation.⁴ More data are needed to decide.
 

CDC 2023-2024 RESP-NET data

The 2023-2024 winter surge (Figure 2), as measured by RESP-NET’s cumulative RSV,influenza and SARS-CoV-2 hospitalization rates for 0- to 5-year-olds,⁵ shows that all three viruses’ seasonal months were normal-ish: late October 2023 start, late December-early January peak, and mid-May 2024 return to baseline. RSV season was approximately 22% less severe by area-under-the-curve calculations compared with 2022-2023, but still worse than prepandemic years.⁶

One wonders if the 2022-2023 RSV season might have been worse but for use of the limited supply of nirsevimab.⁷

Viral Parade

Now we ready ourselves for the 2024-2025 respiratory surge, wondering what nature has in store for us. Will the usual “respiratory virus parade” occur? Will rhinovirus and parainfluenza prevalence bump after a few weeks of schools being in session, adding to the now-usual summer/fall SARS-CoV-2 surge? Note: Twenty-seven states as of Aug. 16 had high SARS-CoV-2 detection in wastewater. Will RSV and influenza start sometime in October/November, peak in January (along with rising SARS-CoV2 activity), followed by a second parainfluenza bump as SARS-CoV-2, influenza, and RSV drop off in April/May? Further, will RSV and influenza seasons be more or less severe than the last 2 years?

Prediction

The overall 2024-2025 respiratory season will be less severe than the past 2 years and hopefully than recent prepandemic years. What is the blueprint for a milder season? First, herd immunity to non-RSV and non-influenza viruses (parainfluenza, rhinovirus, metapneumovirus, adenovirus) in older children should be normalized after 2 years back to usual social activity. So, I expect no mega-seasons from them. The emerging SARS-CoV-2 virus (LB.1) is immunologically close to its recent still-circulating ancestors (KP.2, KP.2.3, KP.³ and KP.3.1.1), so existing SARS-CoV2 herd immunity along with recommended booster vaccine uptake should keep the lid on SARS-CoV2.

Influenza Could Be the Bad News

Which type will dominate? Will a drift/shift occur or vaccine-mismatch reduce vaccine effectiveness? Can we get at least half the population influenza vaccinated, given the vaccine fatigue permeating the US population? The influenza season now underway in the Southern Hemisphere usually helps us predict our season. The Australian May-August 2024 experience (still on an upward trajectory for severity in mid-August) saw no drift/shift or vaccine mismatch. However, this 2024 season has been as severe as 2022 (their worst in a decade). That said, more than 95% has been type A (mostly H1N1 but H3N2 increased in July). So, if our overall 2024-2025 respiratory season is not milder, influenza is the most likely culprit. To reduce chances of influenza being the fly-in-the-ointment, we need to be particularly proactive with seasonal influenza vaccine which is back to the traditional trivalent formulation (one H1N1, one H3N2, and one B type).⁸ All of this could go out the window if avian influenza becomes more transmissible, but that seems unlikely at present.

Mild RSV Season?

RSV season should be blunted because of the increased use of both the remarkably effective CDC-recommended maternal RSV vaccine⁹ (one dose during pregnancy weeks 32 through 36, administered September through January) and of nirsevimab (up to 90% reduction in hospitalizations and ED visits).¹⁰ (See Figure 3.)

I also expect residual disease to occur mostly in younger than 18 month-olds (the “normal” aged population experiencing their first winter), who received no passive immunity (mother RSV unvaccinated and child did not receive nirsevimab). Some disease will still occur in high-risk infants/children. However, unlike active vaccination strategies, a competent immune system is not required to benefit from passive antibody, whether transplacental or directly administered.
 

Deep Thought

What if the traditional RSV seasonal hospitalization surge fails to materialize this season? It could happen. If we could get high acceptance/uptake of maternal vaccine and infant nirsevimab, RSV season could resemble the dramatic drop in rotavirus disease the second year after rotavirus vaccine introduction. We could be asking ourselves — “What happened to RSV?”

Dr. Harrison is professor of pediatrics and pediatric infectious diseases at Children’s Mercy Hospitals and Clinics, Kansas City, Missouri. He said he had no relevant financial disclosures. Email him at [email protected].

References

1. CDC. RSV in Infants and Young Children. Respiratory Syncytial Virus Infection (RSV). June 18, 2024. https://www.cdc.gov/rsv/infants-young-children/index.html.

2. Suss RJ and Simões EAF. Respiratory Syncytial Virus Hospital-Based Burden of Disease in Children Younger Than 5 Respiratory Syncytial Virus Hospital-Based Burden of Disease in Children Younger Than 5 Years, 2015-2022. JAMA Netw Open. 2024;7(4):e247125. doi:10.1001/jamanetworkopen.2024.7125.

3. Winthrop ZA et al. Pediatric Respiratory Syncytial Virus Hospitalizations and Respiratory Support After the COVID-19 Pandemic. JAMA Netw Open. 2024;7(6):e2416852. doi:10.1001/jamanetworkopen.2024.16852.

4. Petros BA et al. Increased Pediatric RSV Case Counts Following the Emergence of SARS-CoV-2 Are Attributable to Increased Testing. medRxiv [Preprint]. 2024 Feb 12:2024.02.06.24302387. doi: 10.1101/2024.02.06.24302387.

5. Rates of Laboratory-Confirmed RSV, COVID-19, and Flu Hospitalizations from the RESP-NET Surveillance Systems. Centers for Disease Control and Prevention. https://data.cdc.gov/Public-Health-Surveillance/Rates-of-Laboratory-Confirmed-RSV-COVID-19-and-Flu/kvib-3txy/about_data.

6. CDC. Evaluating the 2023-2024 Respiratory Disease Season Outlook. CFA: Qualitative Assessments. August 14, 2024. https://www.cdc.gov/cfa-qualitative-assessments/php/data-research/2023-2024-season-outlook-retro.html.

7. Health Alert Network (HAN). Limited Availability of Nirsevimab in the United States—Interim CDC Recommendations to Protect Infants from Respiratory Syncytial Virus (RSV) during the 2023–2024 Respiratory Virus Season. October 23, 2023. https://emergency.cdc.gov/han/2023/han00499.asp.

8. CDC. Information for the 2024-2025 Flu Season. Centers for Disease Control and Prevention. March 14, 2024. https://www.cdc.gov/flu/season/faq-flu-season-2024-2025.htm.

9. Kampmann B et al. Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants. N Engl J Med. 2023 Apr 20;388(16):1451-1464. doi: 10.1056/NEJMoa2216480.

10. Moline HL. Early Estimate of Nirsevimab Effectiveness for Prevention of Respiratory Syncytial Virus–Associated Hospitalization Among Infants Entering Their First Respiratory Syncytial Virus Season — New Vaccine Surveillance Network, October 2023–February 2024. MMWR Morb Mortal Wkly Rep. 2024;73. doi: 10.15585/mmwr.mm7309a4.

To the Editor:
Crusted scabies (formerly known as Norwegian scabies) is a rare and highly contagious variant of scabies, in which the skin is infested with thousands to millions of Sarcoptes scabiei var hominis mites. We present a case of skin changes that were misdiagnosed as atopic dermatitis, seborrhea, xerosis, and drug eruption on initial presentation, which prompted treatment with a corticosteroid that inadvertently caused progression to crusted scabies.

A 79-year-old woman who uses a wheelchair presented to the clinic with skin changes that consisted of diffuse, severely pruritic, erythematous plaques on the head, neck, trunk, face, and extremities of 2 years’ duration. She had a medical history of hyperlipidemia, hypertension, and hyperglycemia, as well as a stroke that required hospitalization 2 years prior to the onset of the skin changes. She had no history of allergies.

Prior clinical diagnoses by primary care and dermatology included xerosis, atopic dermatitis, seborrhea, and drug eruption. She was treated with a mid-potency topical corticosteroid (triamcinolone acetonide cream 0.1%) twice daily and prednisone 40 mg once daily for 2- to 4-week courses over an 8-month period without reduction in symptoms.

Physical examination at the current presentation revealed golden, crusted, fine, powdery but slightly sticky flakes that spread diffusely across the entire body and came off in crumbles with a simple touch. These widespread crusts were easily visible on clothing. There was underlying diffuse erythema beneath the flaking skin on the trunk and proximal extremities. The scale and shedding skin laid in piles on the patient’s lap and resembled brown sugar (Figure 1). The patient also reported decreased hand function and dexterity due to the yellowbrown, thick, crusty plaques that had developed on both the palmar and dorsal sides of the hands (Figure 2). Erythematous plaques on the scalp, forehead, and inner ears resembled seborrhea (Figure 3). Pruritus severity was rated by the patient as 10 of 10, and she scratched her skin the entire time she was in the clinic. The patient was emotional and stated that she had not been able to sleep due to the discomfort. We suspected scabies, and the patient was reassured to learn that it could be confirmed with a simple skin scrape test.

The crusted lesions on the patient's hands were scraped with a #15-blade scalpel, and a routine potassium hydroxide mount was performed. The skin scrapings were placed on a slide with a drop of 10% potassium hydroxide and observed under low-power (×10) and high-power (×40) microscopy, which revealed thousands of mites and eggs (along with previously hatched eggs) (Figure 4) and quickly confirmed a diagnosis of crusted scabies.an extremely contagious form of scabies seen in older patients with compromised immune systems, malnutrition, or disabilities. The patient was prescribed oral ivermectin (3 mg dosed at 200 μg/kg of body weight) and topical permethrin 5%, neither of which she took, as she died of a COVID-19 infection complication 3 days after this diagnostic clinic visit.

Classic and crusted scabies are both caused by infestation of the Sarcoptes scabiei var hominis mite. Classic scabies is a result of an infestation of a small number of mites (commonly 5–15 mites), while crusted scabies is due to hyperinfestation by as many as millions of mites, the latter often requiring more aggressive treatment. The mites are first transmitted to humans by either skin-toskin contact or fomites on bedding and clothing. The scabies mite undergoes 4 life cycle stages: egg, larvae, nymph, and adult. Once female mites are transmitted, they burrow under the skin and lay 2 to 3 eggs per day. The eggs hatch within 3 to 4 days, after which the larvae migrate to the skin surface. The larval stage lasts for 3 to 4 days, during which the larvae burrow into the stratum corneum to create molting pouches, until they molt into slightly larger nymphs. Nymphs can be found in hair follicles or molting pouches until they further molt within 3 to 4 days into adults, which are round, saclike mites. The adult male and female mites then mate, leaving the female fertile for the rest of her 1- to 2-month lifespan. Impregnated female mites traverse the skin surface in search of a burrow site, using the pulvilli on the anterior aspect of 2 legs to hold onto the skin. Once burrowed, the female mite continues to lay eggs for the rest of her life, with approximately 10% of her eggs resulting in adult mites. Male mites feed in shallow pits of the skin until they find a female burrow site for mating.¹ This continuous life cycle of the scabies mite gives rise to highly transmissible, pruritic skin excoriations, as demonstrated in our patient.

The skin has a relatively late inflammatory and adaptive immune response to scabies, typically occurring 4 to 6 weeks after the initial infestation.² This delayed inflammatory response and onset of symptoms may be due to the scabies mite’s ability to alter aspects of the host’s immune response, which differs in classic vs crusted scabies. In classic scabies, there is a predominance of CD4+ T cells in the dermis and minimal CD8+ T cells. The opposite is true in crusted scabies— there is an overwhelming infiltration of CD8+ T cells and minimal CD4+ T cells.³ The CD8+ T-cell predominance in crusted scabies is hypothesized to be the cause of keratinocyte apoptosis, resulting in epidermal hyperproliferation. Keratinocyte apoptosis also secretes cytokines, which may lead to the immunologic targeting of healthy skin cells. The damage of healthy dermal cells contributes to the inability of the skin’s immune system to mount an effective response, allowing the parasite to grow uncontrollably in patients with crusted scabies.⁴

This ineffective immune response is further exacerbated by corticosteroids, which are commonly prescribed for pruritus experienced by patients with scabies infestations. The mechanism of action of corticosteroids is the production of anti-inflammatory, antimitotic, and immunosuppressive effects.⁵ Because the integumentary immune system is imbalanced during crusted scabies infestation, the immunosuppressive mechanism of oral and topical corticosteroids further reduces the cellular immune response to scabies. The flourishing of the scabies mites along with keratinocyte apoptosis⁴ results in the development of hyperkeratotic skin crusting, most frequently on the palms, soles, arms, and legs. Risk factors for crusted scabies include immunosuppression, hospitalization, crowded living conditions, and poor hygiene, though no known risk factors were documented in up to 42% (33/78) of patients with crusted scabies in one study.⁶

Patients with crusted scabies typically present with generalized, poorly defined, erythematous, fissured plaques covered by scaling and crusts. Plaques on bony prominences such as finger articulations and elbows may have a thick verrucous aspect.¹ Skin flaking that resembles brown sugar—a mixture of white sugar and molasses—is a clue to the diagnosis of crusted scabies. Brown sugar has a slightly sandy and sticky texture that ranges in color from very light brown to very dark brown. When present, flakes always appears slightly lighter than the patient’s skin tone. Although skin burrows are pathognomonic and clinically recognizable features of scabies, these burrows can be disguised by lesions, such as the hyperkeratotic plaques seen in our patient. The lesions may or may not be associated with pruritus, which may occur only at night, and bacterial superinfection has been reported in severe cases of crusted scabies,⁷ as scratching can cause sores, which may lead to infection. In severe cases, the constant scratching could lead to sepsis if the infection enters the bloodstream.⁸ Another symptom of scabies is a rash that causes small bumps that tend to form in a line, resembling small bites, hives, or pimples, and scaly plaques can lead to misdiagnosis as atopic dermatitis.

Treatment often is delayed due to misdiagnosis, as seen in our patient. Common misdiagnoses include atopic dermatitis, pityriasis rosea, systemic lupus erythematosus, bullous pemphigoid, lichen planus, pediculosis corporis, seborrheic scalp dermatitis, and adverse drug reactions.⁹ Patients with extensive infestations of crusted scabies should be treated with a 4-week course of permethrin cream 5% daily for 1 week, then twice per week until resolved, and oral ivermectin 200 μg/kg dosed 1 week apart for up to 4 weeks, if needed.¹ Topical permethrin works by producing a selective neurotoxic effect on invertebrates such as scabies mites, which disrupts the function of voltage-gated sodium channels, thereby paralyzing the adult mites to halt the spread of infestation. However, treatment with topical medications can be difficult due to the thick crusts that have formed, which make it more challenging for the skin to properly absorb the treatment. Additionally, surgical debridement as an adjunct procedure has been done to improve the effectiveness of topical medications by removing all the mites in skin.¹⁰ On the other hand, the mechanism in which ivermectin treats scabies infestations is poorly understood. Current research suggests that ivermectin works by causing persistent opening of pH-gated chloride channels in scabies mites.¹¹ There is emerging concern for drug resistance to these scabicides,¹² revealing a need for further research of treatment options.

Patients with crusted scabies can have an extremely large number of mites (up to 2 million), making them more infectious than patients with classic scabies.¹³ As a result, it is imperative to reduce environmental transmission and risk for reinfection with mites during treatment. Because crusted scabies is transmitted by prolonged skinto- skin contact or by contact with personal items of an infected person (eg, bedding, clothing), treatment guidelines require all clothing, bedding, and towels of a patient with scabies to be machine-washed and dried with hot water and hot dryer cycles. If an item cannot be washed, it should be stored in a sealed plastic bag for 1 week, as scabies mites cannot survive more than 2 to 3 days away from their host of human skin.¹³ Treatment of close contacts of patients with scabies is recommended, as well as for those in endemic areas or closed communities, such as nursing homes or jails.

To the Editor:
Crusted scabies (formerly known as Norwegian scabies) is a rare and highly contagious variant of scabies, in which the skin is infested with thousands to millions of Sarcoptes scabiei var hominis mites. We present a case of skin changes that were misdiagnosed as atopic dermatitis, seborrhea, xerosis, and drug eruption on initial presentation, which prompted treatment with a corticosteroid that inadvertently caused progression to crusted scabies.

A 79-year-old woman who uses a wheelchair presented to the clinic with skin changes that consisted of diffuse, severely pruritic, erythematous plaques on the head, neck, trunk, face, and extremities of 2 years’ duration. She had a medical history of hyperlipidemia, hypertension, and hyperglycemia, as well as a stroke that required hospitalization 2 years prior to the onset of the skin changes. She had no history of allergies.

Prior clinical diagnoses by primary care and dermatology included xerosis, atopic dermatitis, seborrhea, and drug eruption. She was treated with a mid-potency topical corticosteroid (triamcinolone acetonide cream 0.1%) twice daily and prednisone 40 mg once daily for 2- to 4-week courses over an 8-month period without reduction in symptoms.

Physical examination at the current presentation revealed golden, crusted, fine, powdery but slightly sticky flakes that spread diffusely across the entire body and came off in crumbles with a simple touch. These widespread crusts were easily visible on clothing. There was underlying diffuse erythema beneath the flaking skin on the trunk and proximal extremities. The scale and shedding skin laid in piles on the patient’s lap and resembled brown sugar (Figure 1). The patient also reported decreased hand function and dexterity due to the yellowbrown, thick, crusty plaques that had developed on both the palmar and dorsal sides of the hands (Figure 2). Erythematous plaques on the scalp, forehead, and inner ears resembled seborrhea (Figure 3). Pruritus severity was rated by the patient as 10 of 10, and she scratched her skin the entire time she was in the clinic. The patient was emotional and stated that she had not been able to sleep due to the discomfort. We suspected scabies, and the patient was reassured to learn that it could be confirmed with a simple skin scrape test.

The crusted lesions on the patient's hands were scraped with a #15-blade scalpel, and a routine potassium hydroxide mount was performed. The skin scrapings were placed on a slide with a drop of 10% potassium hydroxide and observed under low-power (×10) and high-power (×40) microscopy, which revealed thousands of mites and eggs (along with previously hatched eggs) (Figure 4) and quickly confirmed a diagnosis of crusted scabies.an extremely contagious form of scabies seen in older patients with compromised immune systems, malnutrition, or disabilities. The patient was prescribed oral ivermectin (3 mg dosed at 200 μg/kg of body weight) and topical permethrin 5%, neither of which she took, as she died of a COVID-19 infection complication 3 days after this diagnostic clinic visit.

Classic and crusted scabies are both caused by infestation of the Sarcoptes scabiei var hominis mite. Classic scabies is a result of an infestation of a small number of mites (commonly 5–15 mites), while crusted scabies is due to hyperinfestation by as many as millions of mites, the latter often requiring more aggressive treatment. The mites are first transmitted to humans by either skin-toskin contact or fomites on bedding and clothing. The scabies mite undergoes 4 life cycle stages: egg, larvae, nymph, and adult. Once female mites are transmitted, they burrow under the skin and lay 2 to 3 eggs per day. The eggs hatch within 3 to 4 days, after which the larvae migrate to the skin surface. The larval stage lasts for 3 to 4 days, during which the larvae burrow into the stratum corneum to create molting pouches, until they molt into slightly larger nymphs. Nymphs can be found in hair follicles or molting pouches until they further molt within 3 to 4 days into adults, which are round, saclike mites. The adult male and female mites then mate, leaving the female fertile for the rest of her 1- to 2-month lifespan. Impregnated female mites traverse the skin surface in search of a burrow site, using the pulvilli on the anterior aspect of 2 legs to hold onto the skin. Once burrowed, the female mite continues to lay eggs for the rest of her life, with approximately 10% of her eggs resulting in adult mites. Male mites feed in shallow pits of the skin until they find a female burrow site for mating.¹ This continuous life cycle of the scabies mite gives rise to highly transmissible, pruritic skin excoriations, as demonstrated in our patient.

The skin has a relatively late inflammatory and adaptive immune response to scabies, typically occurring 4 to 6 weeks after the initial infestation.² This delayed inflammatory response and onset of symptoms may be due to the scabies mite’s ability to alter aspects of the host’s immune response, which differs in classic vs crusted scabies. In classic scabies, there is a predominance of CD4+ T cells in the dermis and minimal CD8+ T cells. The opposite is true in crusted scabies— there is an overwhelming infiltration of CD8+ T cells and minimal CD4+ T cells.³ The CD8+ T-cell predominance in crusted scabies is hypothesized to be the cause of keratinocyte apoptosis, resulting in epidermal hyperproliferation. Keratinocyte apoptosis also secretes cytokines, which may lead to the immunologic targeting of healthy skin cells. The damage of healthy dermal cells contributes to the inability of the skin’s immune system to mount an effective response, allowing the parasite to grow uncontrollably in patients with crusted scabies.⁴

This ineffective immune response is further exacerbated by corticosteroids, which are commonly prescribed for pruritus experienced by patients with scabies infestations. The mechanism of action of corticosteroids is the production of anti-inflammatory, antimitotic, and immunosuppressive effects.⁵ Because the integumentary immune system is imbalanced during crusted scabies infestation, the immunosuppressive mechanism of oral and topical corticosteroids further reduces the cellular immune response to scabies. The flourishing of the scabies mites along with keratinocyte apoptosis⁴ results in the development of hyperkeratotic skin crusting, most frequently on the palms, soles, arms, and legs. Risk factors for crusted scabies include immunosuppression, hospitalization, crowded living conditions, and poor hygiene, though no known risk factors were documented in up to 42% (33/78) of patients with crusted scabies in one study.⁶

Patients with crusted scabies typically present with generalized, poorly defined, erythematous, fissured plaques covered by scaling and crusts. Plaques on bony prominences such as finger articulations and elbows may have a thick verrucous aspect.¹ Skin flaking that resembles brown sugar—a mixture of white sugar and molasses—is a clue to the diagnosis of crusted scabies. Brown sugar has a slightly sandy and sticky texture that ranges in color from very light brown to very dark brown. When present, flakes always appears slightly lighter than the patient’s skin tone. Although skin burrows are pathognomonic and clinically recognizable features of scabies, these burrows can be disguised by lesions, such as the hyperkeratotic plaques seen in our patient. The lesions may or may not be associated with pruritus, which may occur only at night, and bacterial superinfection has been reported in severe cases of crusted scabies,⁷ as scratching can cause sores, which may lead to infection. In severe cases, the constant scratching could lead to sepsis if the infection enters the bloodstream.⁸ Another symptom of scabies is a rash that causes small bumps that tend to form in a line, resembling small bites, hives, or pimples, and scaly plaques can lead to misdiagnosis as atopic dermatitis.

Treatment often is delayed due to misdiagnosis, as seen in our patient. Common misdiagnoses include atopic dermatitis, pityriasis rosea, systemic lupus erythematosus, bullous pemphigoid, lichen planus, pediculosis corporis, seborrheic scalp dermatitis, and adverse drug reactions.⁹ Patients with extensive infestations of crusted scabies should be treated with a 4-week course of permethrin cream 5% daily for 1 week, then twice per week until resolved, and oral ivermectin 200 μg/kg dosed 1 week apart for up to 4 weeks, if needed.¹ Topical permethrin works by producing a selective neurotoxic effect on invertebrates such as scabies mites, which disrupts the function of voltage-gated sodium channels, thereby paralyzing the adult mites to halt the spread of infestation. However, treatment with topical medications can be difficult due to the thick crusts that have formed, which make it more challenging for the skin to properly absorb the treatment. Additionally, surgical debridement as an adjunct procedure has been done to improve the effectiveness of topical medications by removing all the mites in skin.¹⁰ On the other hand, the mechanism in which ivermectin treats scabies infestations is poorly understood. Current research suggests that ivermectin works by causing persistent opening of pH-gated chloride channels in scabies mites.¹¹ There is emerging concern for drug resistance to these scabicides,¹² revealing a need for further research of treatment options.

Patients with crusted scabies can have an extremely large number of mites (up to 2 million), making them more infectious than patients with classic scabies.¹³ As a result, it is imperative to reduce environmental transmission and risk for reinfection with mites during treatment. Because crusted scabies is transmitted by prolonged skinto- skin contact or by contact with personal items of an infected person (eg, bedding, clothing), treatment guidelines require all clothing, bedding, and towels of a patient with scabies to be machine-washed and dried with hot water and hot dryer cycles. If an item cannot be washed, it should be stored in a sealed plastic bag for 1 week, as scabies mites cannot survive more than 2 to 3 days away from their host of human skin.¹³ Treatment of close contacts of patients with scabies is recommended, as well as for those in endemic areas or closed communities, such as nursing homes or jails.

To the Editor:
Crusted scabies (formerly known as Norwegian scabies) is a rare and highly contagious variant of scabies, in which the skin is infested with thousands to millions of Sarcoptes scabiei var hominis mites. We present a case of skin changes that were misdiagnosed as atopic dermatitis, seborrhea, xerosis, and drug eruption on initial presentation, which prompted treatment with a corticosteroid that inadvertently caused progression to crusted scabies.

A 79-year-old woman who uses a wheelchair presented to the clinic with skin changes that consisted of diffuse, severely pruritic, erythematous plaques on the head, neck, trunk, face, and extremities of 2 years’ duration. She had a medical history of hyperlipidemia, hypertension, and hyperglycemia, as well as a stroke that required hospitalization 2 years prior to the onset of the skin changes. She had no history of allergies.

Prior clinical diagnoses by primary care and dermatology included xerosis, atopic dermatitis, seborrhea, and drug eruption. She was treated with a mid-potency topical corticosteroid (triamcinolone acetonide cream 0.1%) twice daily and prednisone 40 mg once daily for 2- to 4-week courses over an 8-month period without reduction in symptoms.

Physical examination at the current presentation revealed golden, crusted, fine, powdery but slightly sticky flakes that spread diffusely across the entire body and came off in crumbles with a simple touch. These widespread crusts were easily visible on clothing. There was underlying diffuse erythema beneath the flaking skin on the trunk and proximal extremities. The scale and shedding skin laid in piles on the patient’s lap and resembled brown sugar (Figure 1). The patient also reported decreased hand function and dexterity due to the yellowbrown, thick, crusty plaques that had developed on both the palmar and dorsal sides of the hands (Figure 2). Erythematous plaques on the scalp, forehead, and inner ears resembled seborrhea (Figure 3). Pruritus severity was rated by the patient as 10 of 10, and she scratched her skin the entire time she was in the clinic. The patient was emotional and stated that she had not been able to sleep due to the discomfort. We suspected scabies, and the patient was reassured to learn that it could be confirmed with a simple skin scrape test.

The crusted lesions on the patient's hands were scraped with a #15-blade scalpel, and a routine potassium hydroxide mount was performed. The skin scrapings were placed on a slide with a drop of 10% potassium hydroxide and observed under low-power (×10) and high-power (×40) microscopy, which revealed thousands of mites and eggs (along with previously hatched eggs) (Figure 4) and quickly confirmed a diagnosis of crusted scabies.an extremely contagious form of scabies seen in older patients with compromised immune systems, malnutrition, or disabilities. The patient was prescribed oral ivermectin (3 mg dosed at 200 μg/kg of body weight) and topical permethrin 5%, neither of which she took, as she died of a COVID-19 infection complication 3 days after this diagnostic clinic visit.

Classic and crusted scabies are both caused by infestation of the Sarcoptes scabiei var hominis mite. Classic scabies is a result of an infestation of a small number of mites (commonly 5–15 mites), while crusted scabies is due to hyperinfestation by as many as millions of mites, the latter often requiring more aggressive treatment. The mites are first transmitted to humans by either skin-toskin contact or fomites on bedding and clothing. The scabies mite undergoes 4 life cycle stages: egg, larvae, nymph, and adult. Once female mites are transmitted, they burrow under the skin and lay 2 to 3 eggs per day. The eggs hatch within 3 to 4 days, after which the larvae migrate to the skin surface. The larval stage lasts for 3 to 4 days, during which the larvae burrow into the stratum corneum to create molting pouches, until they molt into slightly larger nymphs. Nymphs can be found in hair follicles or molting pouches until they further molt within 3 to 4 days into adults, which are round, saclike mites. The adult male and female mites then mate, leaving the female fertile for the rest of her 1- to 2-month lifespan. Impregnated female mites traverse the skin surface in search of a burrow site, using the pulvilli on the anterior aspect of 2 legs to hold onto the skin. Once burrowed, the female mite continues to lay eggs for the rest of her life, with approximately 10% of her eggs resulting in adult mites. Male mites feed in shallow pits of the skin until they find a female burrow site for mating.¹ This continuous life cycle of the scabies mite gives rise to highly transmissible, pruritic skin excoriations, as demonstrated in our patient.

The skin has a relatively late inflammatory and adaptive immune response to scabies, typically occurring 4 to 6 weeks after the initial infestation.² This delayed inflammatory response and onset of symptoms may be due to the scabies mite’s ability to alter aspects of the host’s immune response, which differs in classic vs crusted scabies. In classic scabies, there is a predominance of CD4+ T cells in the dermis and minimal CD8+ T cells. The opposite is true in crusted scabies— there is an overwhelming infiltration of CD8+ T cells and minimal CD4+ T cells.³ The CD8+ T-cell predominance in crusted scabies is hypothesized to be the cause of keratinocyte apoptosis, resulting in epidermal hyperproliferation. Keratinocyte apoptosis also secretes cytokines, which may lead to the immunologic targeting of healthy skin cells. The damage of healthy dermal cells contributes to the inability of the skin’s immune system to mount an effective response, allowing the parasite to grow uncontrollably in patients with crusted scabies.⁴

This ineffective immune response is further exacerbated by corticosteroids, which are commonly prescribed for pruritus experienced by patients with scabies infestations. The mechanism of action of corticosteroids is the production of anti-inflammatory, antimitotic, and immunosuppressive effects.⁵ Because the integumentary immune system is imbalanced during crusted scabies infestation, the immunosuppressive mechanism of oral and topical corticosteroids further reduces the cellular immune response to scabies. The flourishing of the scabies mites along with keratinocyte apoptosis⁴ results in the development of hyperkeratotic skin crusting, most frequently on the palms, soles, arms, and legs. Risk factors for crusted scabies include immunosuppression, hospitalization, crowded living conditions, and poor hygiene, though no known risk factors were documented in up to 42% (33/78) of patients with crusted scabies in one study.⁶

Patients with crusted scabies typically present with generalized, poorly defined, erythematous, fissured plaques covered by scaling and crusts. Plaques on bony prominences such as finger articulations and elbows may have a thick verrucous aspect.¹ Skin flaking that resembles brown sugar—a mixture of white sugar and molasses—is a clue to the diagnosis of crusted scabies. Brown sugar has a slightly sandy and sticky texture that ranges in color from very light brown to very dark brown. When present, flakes always appears slightly lighter than the patient’s skin tone. Although skin burrows are pathognomonic and clinically recognizable features of scabies, these burrows can be disguised by lesions, such as the hyperkeratotic plaques seen in our patient. The lesions may or may not be associated with pruritus, which may occur only at night, and bacterial superinfection has been reported in severe cases of crusted scabies,⁷ as scratching can cause sores, which may lead to infection. In severe cases, the constant scratching could lead to sepsis if the infection enters the bloodstream.⁸ Another symptom of scabies is a rash that causes small bumps that tend to form in a line, resembling small bites, hives, or pimples, and scaly plaques can lead to misdiagnosis as atopic dermatitis.

Treatment often is delayed due to misdiagnosis, as seen in our patient. Common misdiagnoses include atopic dermatitis, pityriasis rosea, systemic lupus erythematosus, bullous pemphigoid, lichen planus, pediculosis corporis, seborrheic scalp dermatitis, and adverse drug reactions.⁹ Patients with extensive infestations of crusted scabies should be treated with a 4-week course of permethrin cream 5% daily for 1 week, then twice per week until resolved, and oral ivermectin 200 μg/kg dosed 1 week apart for up to 4 weeks, if needed.¹ Topical permethrin works by producing a selective neurotoxic effect on invertebrates such as scabies mites, which disrupts the function of voltage-gated sodium channels, thereby paralyzing the adult mites to halt the spread of infestation. However, treatment with topical medications can be difficult due to the thick crusts that have formed, which make it more challenging for the skin to properly absorb the treatment. Additionally, surgical debridement as an adjunct procedure has been done to improve the effectiveness of topical medications by removing all the mites in skin.¹⁰ On the other hand, the mechanism in which ivermectin treats scabies infestations is poorly understood. Current research suggests that ivermectin works by causing persistent opening of pH-gated chloride channels in scabies mites.¹¹ There is emerging concern for drug resistance to these scabicides,¹² revealing a need for further research of treatment options.

Patients with crusted scabies can have an extremely large number of mites (up to 2 million), making them more infectious than patients with classic scabies.¹³ As a result, it is imperative to reduce environmental transmission and risk for reinfection with mites during treatment. Because crusted scabies is transmitted by prolonged skinto- skin contact or by contact with personal items of an infected person (eg, bedding, clothing), treatment guidelines require all clothing, bedding, and towels of a patient with scabies to be machine-washed and dried with hot water and hot dryer cycles. If an item cannot be washed, it should be stored in a sealed plastic bag for 1 week, as scabies mites cannot survive more than 2 to 3 days away from their host of human skin.¹³ Treatment of close contacts of patients with scabies is recommended, as well as for those in endemic areas or closed communities, such as nursing homes or jails.