Influenza

How can the immunogenicity and effectiveness of flu vaccines be improved in older adults? Several strategies are available, one being the addition of an adjuvant. For example, the MF59-adjuvanted vaccine has shown superior immunogenicity. However, “we do not have data from controlled and randomized clinical trials showing superior clinical effectiveness versus the standard dose,” Professor Odile Launay, an infectious disease specialist at Cochin Hospital in Paris, France, noted during a press conference. Another option is to increase the antigen dose in the vaccine, creating a high-dose (HD) flu vaccine.

Why is there a need for an HD vaccine? “The elderly population bears the greatest burden from the flu,” explained Launay. “This is due to three factors: An aging immune system, a higher number of comorbidities, and increased frailty.” Standard-dose flu vaccines are seen as offering suboptimal protection for those older than 65 years, which led to the development of a quadrivalent vaccine with four times the antigen dose of standard flu vaccines. This HD vaccine was introduced in France during the 2021/2022 flu season. A real-world cohort study has since been conducted to evaluate its effectiveness in the target population — those aged 65 years or older. The results were recently published in Clinical Microbiology and Infection.

Cohort Study

The study included 405,385 noninstitutionalized people aged 65 years or older matched with 1,621,540 individuals in a 1:4 ratio. The first group received the HD vaccine, while the second group received the standard-dose vaccine. Both the groups had an average age of 77 years, with 56% women, and 51% vaccinated in pharmacies. The majority had been previously vaccinated against flu (91%), and 97% had completed a full COVID-19 vaccination schedule. More than half had at least one chronic illness.

Hospitalization rates for flu — the study’s primary outcome — were 69.5 vs 90.5 per 100,000 person-years in the HD vs standard-dose group. This represented a 23.3% reduction (95% CI, 8.4-35.8; P = .003).
 

Strengths and Limitations

Among the strengths of the study, Launay highlighted the large number of vaccinated participants older than 65 years — more than 7 million — and the widespread use of polymerase chain reaction flu tests in cases of hospitalization for respiratory infections, which improved flu coding in the database used. Additionally, the results were consistent with those of previous studies.

However, limitations included the retrospective design, which did not randomize participants and introduced potential bias. For example, the HD vaccine may have been prioritized for the oldest people or those with multiple comorbidities. Additionally, the 2021/2022 flu season was atypical, with the simultaneous circulation of the flu virus and SARS-CoV-2, as noted by Launay.
 

Conclusion

In conclusion, this first evaluation of the HD flu vaccine’s effectiveness in France showed a 25% reduction in hospitalizations, consistent with existing data covering 12 flu seasons. The vaccine has been available for a longer period in the United States and Northern Europe.

“The latest unpublished data from the 2022/23 season show a 27% reduction in hospitalizations with the HD vaccine in people over 65,” added Launay.

Note: Due to a pricing disagreement with the French government, Sanofi’s HD flu vaccine Efluelda, intended for people older than 65 years, will not be available this year. (See: Withdrawal of the Efluelda Influenza Vaccine: The Academy of Medicine Reacts). However, the company has submitted a dossier for a trivalent form for a return in the 2025/2026 season and is working on developing mRNA vaccines. Additionally, a combined flu/COVID-19 vaccine is currently in development.

The study was funded by Sanofi. Several authors are Sanofi employees. Odile Launay reported conflicts of interest with Sanofi, MSD, Pfizer, GSK, and Moderna.
 

This story was translated from Medscape’s French edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

How can the immunogenicity and effectiveness of flu vaccines be improved in older adults? Several strategies are available, one being the addition of an adjuvant. For example, the MF59-adjuvanted vaccine has shown superior immunogenicity. However, “we do not have data from controlled and randomized clinical trials showing superior clinical effectiveness versus the standard dose,” Professor Odile Launay, an infectious disease specialist at Cochin Hospital in Paris, France, noted during a press conference. Another option is to increase the antigen dose in the vaccine, creating a high-dose (HD) flu vaccine.

Why is there a need for an HD vaccine? “The elderly population bears the greatest burden from the flu,” explained Launay. “This is due to three factors: An aging immune system, a higher number of comorbidities, and increased frailty.” Standard-dose flu vaccines are seen as offering suboptimal protection for those older than 65 years, which led to the development of a quadrivalent vaccine with four times the antigen dose of standard flu vaccines. This HD vaccine was introduced in France during the 2021/2022 flu season. A real-world cohort study has since been conducted to evaluate its effectiveness in the target population — those aged 65 years or older. The results were recently published in Clinical Microbiology and Infection.

Cohort Study

The study included 405,385 noninstitutionalized people aged 65 years or older matched with 1,621,540 individuals in a 1:4 ratio. The first group received the HD vaccine, while the second group received the standard-dose vaccine. Both the groups had an average age of 77 years, with 56% women, and 51% vaccinated in pharmacies. The majority had been previously vaccinated against flu (91%), and 97% had completed a full COVID-19 vaccination schedule. More than half had at least one chronic illness.

Hospitalization rates for flu — the study’s primary outcome — were 69.5 vs 90.5 per 100,000 person-years in the HD vs standard-dose group. This represented a 23.3% reduction (95% CI, 8.4-35.8; P = .003).
 

Strengths and Limitations

Among the strengths of the study, Launay highlighted the large number of vaccinated participants older than 65 years — more than 7 million — and the widespread use of polymerase chain reaction flu tests in cases of hospitalization for respiratory infections, which improved flu coding in the database used. Additionally, the results were consistent with those of previous studies.

However, limitations included the retrospective design, which did not randomize participants and introduced potential bias. For example, the HD vaccine may have been prioritized for the oldest people or those with multiple comorbidities. Additionally, the 2021/2022 flu season was atypical, with the simultaneous circulation of the flu virus and SARS-CoV-2, as noted by Launay.
 

Conclusion

In conclusion, this first evaluation of the HD flu vaccine’s effectiveness in France showed a 25% reduction in hospitalizations, consistent with existing data covering 12 flu seasons. The vaccine has been available for a longer period in the United States and Northern Europe.

“The latest unpublished data from the 2022/23 season show a 27% reduction in hospitalizations with the HD vaccine in people over 65,” added Launay.

Note: Due to a pricing disagreement with the French government, Sanofi’s HD flu vaccine Efluelda, intended for people older than 65 years, will not be available this year. (See: Withdrawal of the Efluelda Influenza Vaccine: The Academy of Medicine Reacts). However, the company has submitted a dossier for a trivalent form for a return in the 2025/2026 season and is working on developing mRNA vaccines. Additionally, a combined flu/COVID-19 vaccine is currently in development.

The study was funded by Sanofi. Several authors are Sanofi employees. Odile Launay reported conflicts of interest with Sanofi, MSD, Pfizer, GSK, and Moderna.
 

This story was translated from Medscape’s French edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

How can the immunogenicity and effectiveness of flu vaccines be improved in older adults? Several strategies are available, one being the addition of an adjuvant. For example, the MF59-adjuvanted vaccine has shown superior immunogenicity. However, “we do not have data from controlled and randomized clinical trials showing superior clinical effectiveness versus the standard dose,” Professor Odile Launay, an infectious disease specialist at Cochin Hospital in Paris, France, noted during a press conference. Another option is to increase the antigen dose in the vaccine, creating a high-dose (HD) flu vaccine.

Why is there a need for an HD vaccine? “The elderly population bears the greatest burden from the flu,” explained Launay. “This is due to three factors: An aging immune system, a higher number of comorbidities, and increased frailty.” Standard-dose flu vaccines are seen as offering suboptimal protection for those older than 65 years, which led to the development of a quadrivalent vaccine with four times the antigen dose of standard flu vaccines. This HD vaccine was introduced in France during the 2021/2022 flu season. A real-world cohort study has since been conducted to evaluate its effectiveness in the target population — those aged 65 years or older. The results were recently published in Clinical Microbiology and Infection.

Cohort Study

The study included 405,385 noninstitutionalized people aged 65 years or older matched with 1,621,540 individuals in a 1:4 ratio. The first group received the HD vaccine, while the second group received the standard-dose vaccine. Both the groups had an average age of 77 years, with 56% women, and 51% vaccinated in pharmacies. The majority had been previously vaccinated against flu (91%), and 97% had completed a full COVID-19 vaccination schedule. More than half had at least one chronic illness.

Hospitalization rates for flu — the study’s primary outcome — were 69.5 vs 90.5 per 100,000 person-years in the HD vs standard-dose group. This represented a 23.3% reduction (95% CI, 8.4-35.8; P = .003).
 

Strengths and Limitations

Among the strengths of the study, Launay highlighted the large number of vaccinated participants older than 65 years — more than 7 million — and the widespread use of polymerase chain reaction flu tests in cases of hospitalization for respiratory infections, which improved flu coding in the database used. Additionally, the results were consistent with those of previous studies.

However, limitations included the retrospective design, which did not randomize participants and introduced potential bias. For example, the HD vaccine may have been prioritized for the oldest people or those with multiple comorbidities. Additionally, the 2021/2022 flu season was atypical, with the simultaneous circulation of the flu virus and SARS-CoV-2, as noted by Launay.
 

Conclusion

In conclusion, this first evaluation of the HD flu vaccine’s effectiveness in France showed a 25% reduction in hospitalizations, consistent with existing data covering 12 flu seasons. The vaccine has been available for a longer period in the United States and Northern Europe.

“The latest unpublished data from the 2022/23 season show a 27% reduction in hospitalizations with the HD vaccine in people over 65,” added Launay.

Note: Due to a pricing disagreement with the French government, Sanofi’s HD flu vaccine Efluelda, intended for people older than 65 years, will not be available this year. (See: Withdrawal of the Efluelda Influenza Vaccine: The Academy of Medicine Reacts). However, the company has submitted a dossier for a trivalent form for a return in the 2025/2026 season and is working on developing mRNA vaccines. Additionally, a combined flu/COVID-19 vaccine is currently in development.

The study was funded by Sanofi. Several authors are Sanofi employees. Odile Launay reported conflicts of interest with Sanofi, MSD, Pfizer, GSK, and Moderna.
 

This story was translated from Medscape’s French edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

This transcript has been edited for clarity. 

I recently saw a ban that has me very worried, concerned, and strongly in opposition. Nassau County, which is about 60 miles east of New York City, out on Long Island, instituted a ban on people wearing masks.

Basically, the standard kind of medical mask would be captured, although I think their aim in doing this was to try to discourage people at political protests from being able to wear masks and hide their identity. They’re basically trying to discourage that. This is particularly triggered by, I think, protests about the invasion of Israel, the war that resulted in Gaza, and the demonstrations that have gone on around the country, with many people masked.

There may be issues about what is acceptable to wear when you go to a demonstration. I don’t claim to know about the civil rights of that. 

In a time at which COVID-19 is flourishing, really on the rebound, expanding fast, and still causing 600 deaths a week; the flu season is going to be upon us soon enough; and there are also concerns about the possibility of avian flu jumping into the human population, it is absolutely the wrong time to single out those who are trying to mask for health reasons. 

Basically, there are two strong reasons. One, there are people out there who wear a medical mask or mask for a medical reason because they have an underlying disease. They may have had a transplant or they may feel they’re immunocompromised for some reason. They worry that, if they don’t wear a mask, they’re going to get an infection from something like COVID-19 or flu, which could really be super-dangerous for them. 

The other reason people mask is to protect their family members. They may have someone who’s immunocompromised in the family, or they’re doing it kindly and altruistically to protect the rest of us and to stop viruses from circulating.

These bans are not taking into account public health. They’re being brought forward in the midst of political heat about demonstrations and political issues. I think they should be opposed. I do not think they should be enacted. 

I think the medical rights of people with disabilities and immunologic disorders, and those who want to mask to prevent getting sick at a time at which infectious diseases are still circulating and killing people, ought to take priority. Public health, in this case, should drive our policies about masks. 
 

Dr. Caplan, director, Division of Medical Ethics, New York University Langone Medical Center, New York, NY, served on Johnson & Johnson’s Panel for Compassionate Drug Use (unpaid position), and is a contributing author and adviser for Medscape.

A version of this article appeared on Medscape.com.

This transcript has been edited for clarity. 

I recently saw a ban that has me very worried, concerned, and strongly in opposition. Nassau County, which is about 60 miles east of New York City, out on Long Island, instituted a ban on people wearing masks.

Basically, the standard kind of medical mask would be captured, although I think their aim in doing this was to try to discourage people at political protests from being able to wear masks and hide their identity. They’re basically trying to discourage that. This is particularly triggered by, I think, protests about the invasion of Israel, the war that resulted in Gaza, and the demonstrations that have gone on around the country, with many people masked.

There may be issues about what is acceptable to wear when you go to a demonstration. I don’t claim to know about the civil rights of that. 

In a time at which COVID-19 is flourishing, really on the rebound, expanding fast, and still causing 600 deaths a week; the flu season is going to be upon us soon enough; and there are also concerns about the possibility of avian flu jumping into the human population, it is absolutely the wrong time to single out those who are trying to mask for health reasons. 

Basically, there are two strong reasons. One, there are people out there who wear a medical mask or mask for a medical reason because they have an underlying disease. They may have had a transplant or they may feel they’re immunocompromised for some reason. They worry that, if they don’t wear a mask, they’re going to get an infection from something like COVID-19 or flu, which could really be super-dangerous for them. 

The other reason people mask is to protect their family members. They may have someone who’s immunocompromised in the family, or they’re doing it kindly and altruistically to protect the rest of us and to stop viruses from circulating.

These bans are not taking into account public health. They’re being brought forward in the midst of political heat about demonstrations and political issues. I think they should be opposed. I do not think they should be enacted. 

I think the medical rights of people with disabilities and immunologic disorders, and those who want to mask to prevent getting sick at a time at which infectious diseases are still circulating and killing people, ought to take priority. Public health, in this case, should drive our policies about masks. 
 

Dr. Caplan, director, Division of Medical Ethics, New York University Langone Medical Center, New York, NY, served on Johnson & Johnson’s Panel for Compassionate Drug Use (unpaid position), and is a contributing author and adviser for Medscape.

A version of this article appeared on Medscape.com.

This transcript has been edited for clarity. 

I recently saw a ban that has me very worried, concerned, and strongly in opposition. Nassau County, which is about 60 miles east of New York City, out on Long Island, instituted a ban on people wearing masks.

Basically, the standard kind of medical mask would be captured, although I think their aim in doing this was to try to discourage people at political protests from being able to wear masks and hide their identity. They’re basically trying to discourage that. This is particularly triggered by, I think, protests about the invasion of Israel, the war that resulted in Gaza, and the demonstrations that have gone on around the country, with many people masked.

There may be issues about what is acceptable to wear when you go to a demonstration. I don’t claim to know about the civil rights of that. 

In a time at which COVID-19 is flourishing, really on the rebound, expanding fast, and still causing 600 deaths a week; the flu season is going to be upon us soon enough; and there are also concerns about the possibility of avian flu jumping into the human population, it is absolutely the wrong time to single out those who are trying to mask for health reasons. 

Basically, there are two strong reasons. One, there are people out there who wear a medical mask or mask for a medical reason because they have an underlying disease. They may have had a transplant or they may feel they’re immunocompromised for some reason. They worry that, if they don’t wear a mask, they’re going to get an infection from something like COVID-19 or flu, which could really be super-dangerous for them. 

The other reason people mask is to protect their family members. They may have someone who’s immunocompromised in the family, or they’re doing it kindly and altruistically to protect the rest of us and to stop viruses from circulating.

These bans are not taking into account public health. They’re being brought forward in the midst of political heat about demonstrations and political issues. I think they should be opposed. I do not think they should be enacted. 

I think the medical rights of people with disabilities and immunologic disorders, and those who want to mask to prevent getting sick at a time at which infectious diseases are still circulating and killing people, ought to take priority. Public health, in this case, should drive our policies about masks. 
 

Dr. Caplan, director, Division of Medical Ethics, New York University Langone Medical Center, New York, NY, served on Johnson & Johnson’s Panel for Compassionate Drug Use (unpaid position), and is a contributing author and adviser for Medscape.

A version of this article appeared on Medscape.com.

What’s the outlook for COVID-19 and flu this fall and winter? It’ll probably be a lot like last year, experts say.

“We currently expect this flu season to be comparable to last year’s season,” said Adrienne Keen, PhD, of the Centers for Disease Control and Prevention’s (CDC) Center for Forecasting and Outbreak Analytics. “We expect this year’s COVID-19 season peak to be similar to last year’s or lower.” The CDC is still analyzing COVID surveillance data from the summer and will update the forecast as more is learned.

For COVID, that means it won’t be as bad as the pandemic years, and for the flu, it’s a typical pre-pandemic season. But status quo does not mean great.

Between October 2023 and April 2024, as many as 75 million people got the flu in the United States, according to CDC estimates, resulting in up to 900,000 hospitalizations and between 17,000 and 100,000 deaths. In 2023, about 900,000 Americans were hospitalized with COVID and 75,000 died.

Other experts agreed with Dr. Keen’s prediction.

But unknowns — such as a COVID variant that takes off quickly or a surprise influenza strain — could knock that forecast flat. Getting vaccinated remains crucial, public health officials stressed. 
 

Predicting COVID

Two key predictors of how bad an upcoming COVID season will be are the cycling of new variants and the population’s immunity (protection from an infectious disease that happens when a population is immune through vaccination or previous infection). 

When new variants go up and immunity goes down, “we tend to see the increase in cases,” said Michael T. Osterholm, PhD, MPH, director of the Center for Infectious Disease Research and Policy and a professor of public health at the University of Minnesota, Minneapolis. But if the number of variants goes down and immunity levels go up, the outlook is more favorable.

The new COVID variant called XEC has been found in at least 25 states. On September 27, the CDC added the variant to the COVID tracker. It now accounts for 6% of US cases. This was expected, as the variant has been circulating in Europe, said Amesh Adalja, MD, a senior scholar and infectious disease expert at the Center for Health Security at Johns Hopkins University, Baltimore, Maryland. 

“There will always be a new variant appearing, and one falling,” he said. “So the fact that this is happening is not surprising.” 

Meanwhile, the summer COVID surge has provided postinfection immunity for some people. “What’s likely is, we are going to see substantial protection of the population for several months based on previous infection and in some cases vaccination,” Dr. Osterholm said. That means protection from serious illness, hospitalizations, and deaths (but not necessarily infection). That protection could last through the year or into early 2025.

The timing of 2024’s winter surge will likely be a bit later than 2023’s, said Andrew Pekosz, PhD, a professor and vice chair of molecular microbiology and immunology at Johns Hopkins University, Baltimore, “peaking just after the Christmas/New Year holiday.”

During the 2023-2024 season, weekly COVID hospitalizations peaked the week of Dec. 30, said Justin Lessler, PhD, a professor of epidemiology at the University of North Carolina at Chapel Hill and a member of the COVID-19 Scenario Modeling Hub.

But variants are unpredictable. “There’s a chance that the XEC variant may take off and spread, or might not,” said Dr. Adalja. As of September 28, the Omicron variant KP.3.1.1 was leading, accounting for 58.7% of US cases, according to the CDC.

While Dr. Adalja agreed that 2024’s COVID season will probably be like 2023’s, “we have to be prepared for cases and hospitalizations going up,” he said, “but not to the point of a crisis.” A return to lockdowns and social distancing is unlikely.

Still, older adults and others at higher risk of getting very sick from COVID should consider masking during travel, said Rajendram Rajnarayanan, PhD, MSc, an associate professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro.
 

Flu Forecasts

Predicting flu season this early is hard, said Jeffrey Shaman, PhD, a professor of environmental health sciences and professor of climate at Colombia University, New York.

“You can look at the CDC forecast and use it as a very loose guide right now,” said Dr. Shaman, who won the CDC’s first “Predict the Influenza Season Challenge” in 2014. “Until there is actually flu, it’s like trying to predict the landfall of a hurricane.” Flu activity remained low as of September 14 (the most current data available), according to the CDC.

When flu activity picks up, typically in mid-October or November, experts look at the dominant strain, exposure to similar strains in previous years, and how well-matched the current flu vaccine is to that dominant strain, Dr. Shaman said. Vaccine makers must make an educated guess months in advance regarding which strain to target, to allow time for production.

The vaccination rate plays a role, too, but that tends to remain constant, Dr. Shaman said. According to the CDC, less than half of adults age 18 and up got a flu vaccination last year.

Experts also consider flu patterns in the Southern Hemisphere, where 2024 flu activity has mostly involved two subtypes of influenza A — H1N1 and H3N2 — and some influenza B, the CDC found.
 

How Well Do This Year’s Vaccines and Viruses Match Up?

The FDA has authorized three updated COVID vaccines for this fall. Novavax targets the JN.1 strain of SARS-CoV-2, the virus that causes COVID-19. Both mRNA vaccines, Moderna and Pfizer, target KP.2, a descendant of JN.1. All three target current predominant variants, and any one of them is recommended by the CDC.

The vaccines are a good “though not perfect match to virtually all the circulating variants of SARS-CoV-2,” said Dr. Pekosz.

Experts said that the shots will protect against the XEC variant. 

“XEC and its sublineages are expected to be the dominant fall/winter variant group,” said Dr. Rajnarayanan. 

This year’s flu vaccines, all trivalent (protecting against three viruses), will target the three strains expected to circulate — H1N1, H3N2, and influenza B (Victoria), according to the CDC.

People should still get vaccinated, Dr. Adalja said, and use home tests for flu and COVID and take antivirals promptly when needed. The goal should not be status quo but rather fewer COVID and flu hospitalizations and deaths.

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

What’s the outlook for COVID-19 and flu this fall and winter? It’ll probably be a lot like last year, experts say.

“We currently expect this flu season to be comparable to last year’s season,” said Adrienne Keen, PhD, of the Centers for Disease Control and Prevention’s (CDC) Center for Forecasting and Outbreak Analytics. “We expect this year’s COVID-19 season peak to be similar to last year’s or lower.” The CDC is still analyzing COVID surveillance data from the summer and will update the forecast as more is learned.

For COVID, that means it won’t be as bad as the pandemic years, and for the flu, it’s a typical pre-pandemic season. But status quo does not mean great.

Between October 2023 and April 2024, as many as 75 million people got the flu in the United States, according to CDC estimates, resulting in up to 900,000 hospitalizations and between 17,000 and 100,000 deaths. In 2023, about 900,000 Americans were hospitalized with COVID and 75,000 died.

Other experts agreed with Dr. Keen’s prediction.

But unknowns — such as a COVID variant that takes off quickly or a surprise influenza strain — could knock that forecast flat. Getting vaccinated remains crucial, public health officials stressed. 
 

Predicting COVID

Two key predictors of how bad an upcoming COVID season will be are the cycling of new variants and the population’s immunity (protection from an infectious disease that happens when a population is immune through vaccination or previous infection). 

When new variants go up and immunity goes down, “we tend to see the increase in cases,” said Michael T. Osterholm, PhD, MPH, director of the Center for Infectious Disease Research and Policy and a professor of public health at the University of Minnesota, Minneapolis. But if the number of variants goes down and immunity levels go up, the outlook is more favorable.

The new COVID variant called XEC has been found in at least 25 states. On September 27, the CDC added the variant to the COVID tracker. It now accounts for 6% of US cases. This was expected, as the variant has been circulating in Europe, said Amesh Adalja, MD, a senior scholar and infectious disease expert at the Center for Health Security at Johns Hopkins University, Baltimore, Maryland. 

“There will always be a new variant appearing, and one falling,” he said. “So the fact that this is happening is not surprising.” 

Meanwhile, the summer COVID surge has provided postinfection immunity for some people. “What’s likely is, we are going to see substantial protection of the population for several months based on previous infection and in some cases vaccination,” Dr. Osterholm said. That means protection from serious illness, hospitalizations, and deaths (but not necessarily infection). That protection could last through the year or into early 2025.

The timing of 2024’s winter surge will likely be a bit later than 2023’s, said Andrew Pekosz, PhD, a professor and vice chair of molecular microbiology and immunology at Johns Hopkins University, Baltimore, “peaking just after the Christmas/New Year holiday.”

During the 2023-2024 season, weekly COVID hospitalizations peaked the week of Dec. 30, said Justin Lessler, PhD, a professor of epidemiology at the University of North Carolina at Chapel Hill and a member of the COVID-19 Scenario Modeling Hub.

But variants are unpredictable. “There’s a chance that the XEC variant may take off and spread, or might not,” said Dr. Adalja. As of September 28, the Omicron variant KP.3.1.1 was leading, accounting for 58.7% of US cases, according to the CDC.

While Dr. Adalja agreed that 2024’s COVID season will probably be like 2023’s, “we have to be prepared for cases and hospitalizations going up,” he said, “but not to the point of a crisis.” A return to lockdowns and social distancing is unlikely.

Still, older adults and others at higher risk of getting very sick from COVID should consider masking during travel, said Rajendram Rajnarayanan, PhD, MSc, an associate professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro.
 

Flu Forecasts

Predicting flu season this early is hard, said Jeffrey Shaman, PhD, a professor of environmental health sciences and professor of climate at Colombia University, New York.

“You can look at the CDC forecast and use it as a very loose guide right now,” said Dr. Shaman, who won the CDC’s first “Predict the Influenza Season Challenge” in 2014. “Until there is actually flu, it’s like trying to predict the landfall of a hurricane.” Flu activity remained low as of September 14 (the most current data available), according to the CDC.

When flu activity picks up, typically in mid-October or November, experts look at the dominant strain, exposure to similar strains in previous years, and how well-matched the current flu vaccine is to that dominant strain, Dr. Shaman said. Vaccine makers must make an educated guess months in advance regarding which strain to target, to allow time for production.

The vaccination rate plays a role, too, but that tends to remain constant, Dr. Shaman said. According to the CDC, less than half of adults age 18 and up got a flu vaccination last year.

Experts also consider flu patterns in the Southern Hemisphere, where 2024 flu activity has mostly involved two subtypes of influenza A — H1N1 and H3N2 — and some influenza B, the CDC found.
 

How Well Do This Year’s Vaccines and Viruses Match Up?

The FDA has authorized three updated COVID vaccines for this fall. Novavax targets the JN.1 strain of SARS-CoV-2, the virus that causes COVID-19. Both mRNA vaccines, Moderna and Pfizer, target KP.2, a descendant of JN.1. All three target current predominant variants, and any one of them is recommended by the CDC.

The vaccines are a good “though not perfect match to virtually all the circulating variants of SARS-CoV-2,” said Dr. Pekosz.

Experts said that the shots will protect against the XEC variant. 

“XEC and its sublineages are expected to be the dominant fall/winter variant group,” said Dr. Rajnarayanan. 

This year’s flu vaccines, all trivalent (protecting against three viruses), will target the three strains expected to circulate — H1N1, H3N2, and influenza B (Victoria), according to the CDC.

People should still get vaccinated, Dr. Adalja said, and use home tests for flu and COVID and take antivirals promptly when needed. The goal should not be status quo but rather fewer COVID and flu hospitalizations and deaths.

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

What’s the outlook for COVID-19 and flu this fall and winter? It’ll probably be a lot like last year, experts say.

“We currently expect this flu season to be comparable to last year’s season,” said Adrienne Keen, PhD, of the Centers for Disease Control and Prevention’s (CDC) Center for Forecasting and Outbreak Analytics. “We expect this year’s COVID-19 season peak to be similar to last year’s or lower.” The CDC is still analyzing COVID surveillance data from the summer and will update the forecast as more is learned.

For COVID, that means it won’t be as bad as the pandemic years, and for the flu, it’s a typical pre-pandemic season. But status quo does not mean great.

Between October 2023 and April 2024, as many as 75 million people got the flu in the United States, according to CDC estimates, resulting in up to 900,000 hospitalizations and between 17,000 and 100,000 deaths. In 2023, about 900,000 Americans were hospitalized with COVID and 75,000 died.

Other experts agreed with Dr. Keen’s prediction.

But unknowns — such as a COVID variant that takes off quickly or a surprise influenza strain — could knock that forecast flat. Getting vaccinated remains crucial, public health officials stressed. 
 

Predicting COVID

Two key predictors of how bad an upcoming COVID season will be are the cycling of new variants and the population’s immunity (protection from an infectious disease that happens when a population is immune through vaccination or previous infection). 

When new variants go up and immunity goes down, “we tend to see the increase in cases,” said Michael T. Osterholm, PhD, MPH, director of the Center for Infectious Disease Research and Policy and a professor of public health at the University of Minnesota, Minneapolis. But if the number of variants goes down and immunity levels go up, the outlook is more favorable.

The new COVID variant called XEC has been found in at least 25 states. On September 27, the CDC added the variant to the COVID tracker. It now accounts for 6% of US cases. This was expected, as the variant has been circulating in Europe, said Amesh Adalja, MD, a senior scholar and infectious disease expert at the Center for Health Security at Johns Hopkins University, Baltimore, Maryland. 

“There will always be a new variant appearing, and one falling,” he said. “So the fact that this is happening is not surprising.” 

Meanwhile, the summer COVID surge has provided postinfection immunity for some people. “What’s likely is, we are going to see substantial protection of the population for several months based on previous infection and in some cases vaccination,” Dr. Osterholm said. That means protection from serious illness, hospitalizations, and deaths (but not necessarily infection). That protection could last through the year or into early 2025.

The timing of 2024’s winter surge will likely be a bit later than 2023’s, said Andrew Pekosz, PhD, a professor and vice chair of molecular microbiology and immunology at Johns Hopkins University, Baltimore, “peaking just after the Christmas/New Year holiday.”

During the 2023-2024 season, weekly COVID hospitalizations peaked the week of Dec. 30, said Justin Lessler, PhD, a professor of epidemiology at the University of North Carolina at Chapel Hill and a member of the COVID-19 Scenario Modeling Hub.

But variants are unpredictable. “There’s a chance that the XEC variant may take off and spread, or might not,” said Dr. Adalja. As of September 28, the Omicron variant KP.3.1.1 was leading, accounting for 58.7% of US cases, according to the CDC.

While Dr. Adalja agreed that 2024’s COVID season will probably be like 2023’s, “we have to be prepared for cases and hospitalizations going up,” he said, “but not to the point of a crisis.” A return to lockdowns and social distancing is unlikely.

Still, older adults and others at higher risk of getting very sick from COVID should consider masking during travel, said Rajendram Rajnarayanan, PhD, MSc, an associate professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro.
 

Flu Forecasts

Predicting flu season this early is hard, said Jeffrey Shaman, PhD, a professor of environmental health sciences and professor of climate at Colombia University, New York.

“You can look at the CDC forecast and use it as a very loose guide right now,” said Dr. Shaman, who won the CDC’s first “Predict the Influenza Season Challenge” in 2014. “Until there is actually flu, it’s like trying to predict the landfall of a hurricane.” Flu activity remained low as of September 14 (the most current data available), according to the CDC.

When flu activity picks up, typically in mid-October or November, experts look at the dominant strain, exposure to similar strains in previous years, and how well-matched the current flu vaccine is to that dominant strain, Dr. Shaman said. Vaccine makers must make an educated guess months in advance regarding which strain to target, to allow time for production.

The vaccination rate plays a role, too, but that tends to remain constant, Dr. Shaman said. According to the CDC, less than half of adults age 18 and up got a flu vaccination last year.

Experts also consider flu patterns in the Southern Hemisphere, where 2024 flu activity has mostly involved two subtypes of influenza A — H1N1 and H3N2 — and some influenza B, the CDC found.
 

How Well Do This Year’s Vaccines and Viruses Match Up?

The FDA has authorized three updated COVID vaccines for this fall. Novavax targets the JN.1 strain of SARS-CoV-2, the virus that causes COVID-19. Both mRNA vaccines, Moderna and Pfizer, target KP.2, a descendant of JN.1. All three target current predominant variants, and any one of them is recommended by the CDC.

The vaccines are a good “though not perfect match to virtually all the circulating variants of SARS-CoV-2,” said Dr. Pekosz.

Experts said that the shots will protect against the XEC variant. 

“XEC and its sublineages are expected to be the dominant fall/winter variant group,” said Dr. Rajnarayanan. 

This year’s flu vaccines, all trivalent (protecting against three viruses), will target the three strains expected to circulate — H1N1, H3N2, and influenza B (Victoria), according to the CDC.

People should still get vaccinated, Dr. Adalja said, and use home tests for flu and COVID and take antivirals promptly when needed. The goal should not be status quo but rather fewer COVID and flu hospitalizations and deaths.

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

As primary care physicians, we are often the first ones patients see when they become infected with influenza. According to Centers for Disease Control and Prevention statistics, approximately 5%-20% of the US population will be infected with influenza every year. Additionally, more than 200,000 of these patients will be hospitalized because of complications related to influenza.

Earlier in September, the World Health Organization (WHO) issued its latest clinical practice guidelines for influenza for the 2024-2025 season. This is a 213-page document aimed at healthcare providers who treat patients infected with influenza. It includes treatment for those with severe and nonsevere influenza infections, those in both the outpatient and hospitalized setting, as well as medication prophylaxis for those exposed to the virus. Additionally, it defines risk estimates for those who are at risk of being hospitalized or dying. In contrast, previous updates focused on management of severe influenza or those at risk of severe influenza.

These guidelines cover recommendations regarding all the antiviral medications for treating influenza used around the world. For the purpose of this article, we will focus on those most commonly used in the United States.

A newer medication discussed was baloxavir. It is recommended to be used for patients with nonsevere influenza who are at high risk for progression to severe disease. The advice is to not use it for those with little risk of progression to severe disease. Oseltamivir is recommended for those with severe infection.

The guidelines recommend against using antibiotics for those who have a low likelihood of having a bacterial coinfection. As primary care doctors, we often prescribe medications to help with symptoms. These guidelines recommend against the use of corticosteroids and antibiotics but did advise that NSAIDs could be used for symptom relief.

One of the important parts of these guidelines is prevention in patients who have been exposed but are asymptomatic. They recommend baloxavir or oseltamivir but only for those patients who are at high risk of being hospitalized if they were to become infected. Any of the antivirals can be used for patients who are exposed to the novel influenza A, which is associated with a higher mortality rate. Caution when prescribing antivirals is recommended in immunocompromised patients because there is more drug resistance seen in these patients.

These updates also discuss the use of different influenza tests. In the outpatient setting, primary doctors don’t have time for test results that may take 2 days to come back. Only rapid tests make the sense in the primary care setting. Additionally, in the age of COVID, it is important to make an accurate diagnosis so we should be testing patients. There is resistance seen with the antivirals we prescribe for influenza so prescribing them empirically without a confirmed diagnosis of influenza may be doing more harm than good.

One gap in these recommendations is vaccination. This topic was not covered at all. It would be helpful to have a strategy in place to prevent infection in populations rather than focusing just on exposed individuals. A discussion of when and who and to vaccinate would be helpful. Research into the effectiveness of vaccines is key and more accurate development of a season’s influenza vaccine would be beneficial. Currently, there is much vaccine misinformation being spread around. Education and information regarding influenza vaccines, especially coming from WHO, is crucial.

Another failure of these recommendations is that the guidelines apply only to those who present within a few days of becoming symptomatic. As family doctors, we know many of our patients self-treat or consult Google. They often don’t come for medical care until they’ve been sick for a week or longer. There are no guidelines for these patients.

In general, these guidelines are comprehensive and do a great job discussing the current medications available. However, more is needed to increase vaccination rates. Patients need to know that if they may be sick with influenza, they need to seek medical care as soon as possible. We, as family doctors, need to do a better job of risk-stratifying our patients and prescribing prophylactic medication when suitable. Every infection we prevent aids in the health of our community and the global population at large.

Dr. Girgis practices family medicine in South River, New Jersey, and is a clinical assistant professor of family medicine at Robert Wood Johnson Medical School, New Brunswick, New Jersey. She has no relevant conflicts of interest.

As primary care physicians, we are often the first ones patients see when they become infected with influenza. According to Centers for Disease Control and Prevention statistics, approximately 5%-20% of the US population will be infected with influenza every year. Additionally, more than 200,000 of these patients will be hospitalized because of complications related to influenza.

Earlier in September, the World Health Organization (WHO) issued its latest clinical practice guidelines for influenza for the 2024-2025 season. This is a 213-page document aimed at healthcare providers who treat patients infected with influenza. It includes treatment for those with severe and nonsevere influenza infections, those in both the outpatient and hospitalized setting, as well as medication prophylaxis for those exposed to the virus. Additionally, it defines risk estimates for those who are at risk of being hospitalized or dying. In contrast, previous updates focused on management of severe influenza or those at risk of severe influenza.

These guidelines cover recommendations regarding all the antiviral medications for treating influenza used around the world. For the purpose of this article, we will focus on those most commonly used in the United States.

A newer medication discussed was baloxavir. It is recommended to be used for patients with nonsevere influenza who are at high risk for progression to severe disease. The advice is to not use it for those with little risk of progression to severe disease. Oseltamivir is recommended for those with severe infection.

The guidelines recommend against using antibiotics for those who have a low likelihood of having a bacterial coinfection. As primary care doctors, we often prescribe medications to help with symptoms. These guidelines recommend against the use of corticosteroids and antibiotics but did advise that NSAIDs could be used for symptom relief.

One of the important parts of these guidelines is prevention in patients who have been exposed but are asymptomatic. They recommend baloxavir or oseltamivir but only for those patients who are at high risk of being hospitalized if they were to become infected. Any of the antivirals can be used for patients who are exposed to the novel influenza A, which is associated with a higher mortality rate. Caution when prescribing antivirals is recommended in immunocompromised patients because there is more drug resistance seen in these patients.

These updates also discuss the use of different influenza tests. In the outpatient setting, primary doctors don’t have time for test results that may take 2 days to come back. Only rapid tests make the sense in the primary care setting. Additionally, in the age of COVID, it is important to make an accurate diagnosis so we should be testing patients. There is resistance seen with the antivirals we prescribe for influenza so prescribing them empirically without a confirmed diagnosis of influenza may be doing more harm than good.

One gap in these recommendations is vaccination. This topic was not covered at all. It would be helpful to have a strategy in place to prevent infection in populations rather than focusing just on exposed individuals. A discussion of when and who and to vaccinate would be helpful. Research into the effectiveness of vaccines is key and more accurate development of a season’s influenza vaccine would be beneficial. Currently, there is much vaccine misinformation being spread around. Education and information regarding influenza vaccines, especially coming from WHO, is crucial.

Another failure of these recommendations is that the guidelines apply only to those who present within a few days of becoming symptomatic. As family doctors, we know many of our patients self-treat or consult Google. They often don’t come for medical care until they’ve been sick for a week or longer. There are no guidelines for these patients.

In general, these guidelines are comprehensive and do a great job discussing the current medications available. However, more is needed to increase vaccination rates. Patients need to know that if they may be sick with influenza, they need to seek medical care as soon as possible. We, as family doctors, need to do a better job of risk-stratifying our patients and prescribing prophylactic medication when suitable. Every infection we prevent aids in the health of our community and the global population at large.

Dr. Girgis practices family medicine in South River, New Jersey, and is a clinical assistant professor of family medicine at Robert Wood Johnson Medical School, New Brunswick, New Jersey. She has no relevant conflicts of interest.

As primary care physicians, we are often the first ones patients see when they become infected with influenza. According to Centers for Disease Control and Prevention statistics, approximately 5%-20% of the US population will be infected with influenza every year. Additionally, more than 200,000 of these patients will be hospitalized because of complications related to influenza.

Earlier in September, the World Health Organization (WHO) issued its latest clinical practice guidelines for influenza for the 2024-2025 season. This is a 213-page document aimed at healthcare providers who treat patients infected with influenza. It includes treatment for those with severe and nonsevere influenza infections, those in both the outpatient and hospitalized setting, as well as medication prophylaxis for those exposed to the virus. Additionally, it defines risk estimates for those who are at risk of being hospitalized or dying. In contrast, previous updates focused on management of severe influenza or those at risk of severe influenza.

These guidelines cover recommendations regarding all the antiviral medications for treating influenza used around the world. For the purpose of this article, we will focus on those most commonly used in the United States.

A newer medication discussed was baloxavir. It is recommended to be used for patients with nonsevere influenza who are at high risk for progression to severe disease. The advice is to not use it for those with little risk of progression to severe disease. Oseltamivir is recommended for those with severe infection.

The guidelines recommend against using antibiotics for those who have a low likelihood of having a bacterial coinfection. As primary care doctors, we often prescribe medications to help with symptoms. These guidelines recommend against the use of corticosteroids and antibiotics but did advise that NSAIDs could be used for symptom relief.

One of the important parts of these guidelines is prevention in patients who have been exposed but are asymptomatic. They recommend baloxavir or oseltamivir but only for those patients who are at high risk of being hospitalized if they were to become infected. Any of the antivirals can be used for patients who are exposed to the novel influenza A, which is associated with a higher mortality rate. Caution when prescribing antivirals is recommended in immunocompromised patients because there is more drug resistance seen in these patients.

These updates also discuss the use of different influenza tests. In the outpatient setting, primary doctors don’t have time for test results that may take 2 days to come back. Only rapid tests make the sense in the primary care setting. Additionally, in the age of COVID, it is important to make an accurate diagnosis so we should be testing patients. There is resistance seen with the antivirals we prescribe for influenza so prescribing them empirically without a confirmed diagnosis of influenza may be doing more harm than good.

One gap in these recommendations is vaccination. This topic was not covered at all. It would be helpful to have a strategy in place to prevent infection in populations rather than focusing just on exposed individuals. A discussion of when and who and to vaccinate would be helpful. Research into the effectiveness of vaccines is key and more accurate development of a season’s influenza vaccine would be beneficial. Currently, there is much vaccine misinformation being spread around. Education and information regarding influenza vaccines, especially coming from WHO, is crucial.

Another failure of these recommendations is that the guidelines apply only to those who present within a few days of becoming symptomatic. As family doctors, we know many of our patients self-treat or consult Google. They often don’t come for medical care until they’ve been sick for a week or longer. There are no guidelines for these patients.

In general, these guidelines are comprehensive and do a great job discussing the current medications available. However, more is needed to increase vaccination rates. Patients need to know that if they may be sick with influenza, they need to seek medical care as soon as possible. We, as family doctors, need to do a better job of risk-stratifying our patients and prescribing prophylactic medication when suitable. Every infection we prevent aids in the health of our community and the global population at large.

Dr. Girgis practices family medicine in South River, New Jersey, and is a clinical assistant professor of family medicine at Robert Wood Johnson Medical School, New Brunswick, New Jersey. She has no relevant conflicts of interest.

Hospitals and laboratories across the United States are grappling with a shortage of Becton Dickinson BACTEC blood culture bottles that threatens to extend at least until September.

In a health advisory, the Centers for Disease Control and Prevention (CDC) warned that the critical shortage could lead to “delays in diagnosis, misdiagnosis, or other challenges” in the management of patients with infectious diseases.

Most blood cultures in the United States are performed using continuous-monitoring blood culture systems; the Becton Dickinson system is used in about half of all US laboratories and is only compatible with the brand’s BACTEC blood culture media bottles.

Healthcare providers, laboratories, healthcare facility administrators, and state, tribal, local, and territorial health departments affected by the shortage “should immediately begin to assess their situations and develop plans and options to mitigate the potential impact,” according to the health advisory.
 

What to Do

To reduce the impact of the shortage, facilities are urged to:

• Determine the type of blood culture bottles they have
• Optimize the use of blood cultures at their facility
• Take steps to prevent blood culture contamination
• Ensure that the appropriate volume of blood is collected for culture
• Assess alternate options for blood cultures
• Work with a nearby facility or send samples to another laboratory

Health departments are advised to contact hospitals and laboratories in their jurisdictions to determine whether the shortage will affect them. Health departments are also encouraged to educate others on the supply shortage, optimal use of blood cultures, and mechanisms for reporting supply chain shortages or interruptions to the Food and Drug Administration (FDA), as well as to help with communication between laboratories and facilities willing to assist others in need.

To further assist affected providers, the CDC, in collaboration with the Infectious Diseases Society of America, hosted a webinar with speakers from Johns Hopkins University, Massachusetts General Hospital, and Vanderbilt University, who shared what their institutions are doing to cope with the shortage and protect patients.
 

Why It Happened

In June, Becton Dickinson warned its customers that they may experience “intermittent delays” in the supply of some BACTEC blood culture media over the coming months because of reduced availability of plastic bottles from its supplier.

In a July 22 update, the company said the supplier issues were “more complex” than originally communicated and it is taking steps to “resolve this challenge as quickly as possible.”

In July, the FDA published a letter to healthcare providers acknowledging the supply disruptions and recommended strategies to preserve the supply for patients at highest risk.

Becton Dickinson has promised an update by September to this “dynamic and evolving situation.”

A version of this article appeared on Medscape.com.

Hospitals and laboratories across the United States are grappling with a shortage of Becton Dickinson BACTEC blood culture bottles that threatens to extend at least until September.

In a health advisory, the Centers for Disease Control and Prevention (CDC) warned that the critical shortage could lead to “delays in diagnosis, misdiagnosis, or other challenges” in the management of patients with infectious diseases.

Most blood cultures in the United States are performed using continuous-monitoring blood culture systems; the Becton Dickinson system is used in about half of all US laboratories and is only compatible with the brand’s BACTEC blood culture media bottles.

Healthcare providers, laboratories, healthcare facility administrators, and state, tribal, local, and territorial health departments affected by the shortage “should immediately begin to assess their situations and develop plans and options to mitigate the potential impact,” according to the health advisory.
 

What to Do

To reduce the impact of the shortage, facilities are urged to:

• Determine the type of blood culture bottles they have
• Optimize the use of blood cultures at their facility
• Take steps to prevent blood culture contamination
• Ensure that the appropriate volume of blood is collected for culture
• Assess alternate options for blood cultures
• Work with a nearby facility or send samples to another laboratory

Health departments are advised to contact hospitals and laboratories in their jurisdictions to determine whether the shortage will affect them. Health departments are also encouraged to educate others on the supply shortage, optimal use of blood cultures, and mechanisms for reporting supply chain shortages or interruptions to the Food and Drug Administration (FDA), as well as to help with communication between laboratories and facilities willing to assist others in need.

To further assist affected providers, the CDC, in collaboration with the Infectious Diseases Society of America, hosted a webinar with speakers from Johns Hopkins University, Massachusetts General Hospital, and Vanderbilt University, who shared what their institutions are doing to cope with the shortage and protect patients.
 

Why It Happened

In June, Becton Dickinson warned its customers that they may experience “intermittent delays” in the supply of some BACTEC blood culture media over the coming months because of reduced availability of plastic bottles from its supplier.

In a July 22 update, the company said the supplier issues were “more complex” than originally communicated and it is taking steps to “resolve this challenge as quickly as possible.”

In July, the FDA published a letter to healthcare providers acknowledging the supply disruptions and recommended strategies to preserve the supply for patients at highest risk.

Becton Dickinson has promised an update by September to this “dynamic and evolving situation.”

A version of this article appeared on Medscape.com.

Hospitals and laboratories across the United States are grappling with a shortage of Becton Dickinson BACTEC blood culture bottles that threatens to extend at least until September.

In a health advisory, the Centers for Disease Control and Prevention (CDC) warned that the critical shortage could lead to “delays in diagnosis, misdiagnosis, or other challenges” in the management of patients with infectious diseases.

Most blood cultures in the United States are performed using continuous-monitoring blood culture systems; the Becton Dickinson system is used in about half of all US laboratories and is only compatible with the brand’s BACTEC blood culture media bottles.

Healthcare providers, laboratories, healthcare facility administrators, and state, tribal, local, and territorial health departments affected by the shortage “should immediately begin to assess their situations and develop plans and options to mitigate the potential impact,” according to the health advisory.
 

What to Do

To reduce the impact of the shortage, facilities are urged to:

• Determine the type of blood culture bottles they have
• Optimize the use of blood cultures at their facility
• Take steps to prevent blood culture contamination
• Ensure that the appropriate volume of blood is collected for culture
• Assess alternate options for blood cultures
• Work with a nearby facility or send samples to another laboratory

Health departments are advised to contact hospitals and laboratories in their jurisdictions to determine whether the shortage will affect them. Health departments are also encouraged to educate others on the supply shortage, optimal use of blood cultures, and mechanisms for reporting supply chain shortages or interruptions to the Food and Drug Administration (FDA), as well as to help with communication between laboratories and facilities willing to assist others in need.

To further assist affected providers, the CDC, in collaboration with the Infectious Diseases Society of America, hosted a webinar with speakers from Johns Hopkins University, Massachusetts General Hospital, and Vanderbilt University, who shared what their institutions are doing to cope with the shortage and protect patients.
 

Why It Happened

In June, Becton Dickinson warned its customers that they may experience “intermittent delays” in the supply of some BACTEC blood culture media over the coming months because of reduced availability of plastic bottles from its supplier.

In a July 22 update, the company said the supplier issues were “more complex” than originally communicated and it is taking steps to “resolve this challenge as quickly as possible.”

In July, the FDA published a letter to healthcare providers acknowledging the supply disruptions and recommended strategies to preserve the supply for patients at highest risk.

Becton Dickinson has promised an update by September to this “dynamic and evolving situation.”

A version of this article appeared on Medscape.com.

The link between influenza infection and a rise in short-term risk for acute myocardial infarction (MI) has been reaffirmed in a new study, which showed the risk appears to be particularly elevated in individuals with no prior diagnosis of coronary artery disease.

“Our study results confirm previous findings of an increased risk of MI during or immediately following acute severe flu infection and raises the idea of giving prophylactic anticoagulation to these patients,” reported Patricia Bruijning-Verhagen, MD, University Medical Center Utrecht, the Netherlands, who is the senior author of the study, which was published online in NEJM Evidence.

“Our results also change things — in that we now know the focus should be on people without a history of cardiovascular disease — and highlight the importance of flu vaccination, particularly for this group,” she pointed out.

The observational, self-controlled, case-series study linked laboratory records on respiratory virus polymerase chain reaction (PCR) testing from 16 laboratories in the Netherlands to national mortality, hospitalization, medication, and administrative registries. Investigators compared the incidence of acute MI during the risk period — days 1-7 after influenza infection — with that in the control period — 1 year before and 51 weeks after the risk period.

The researchers found 26,221 positive PCR tests for influenza, constituting 23,405 unique influenza illness episodes. Of the episodes of acute MI occurring in the year before or the year after confirmed influenza infection and included in the analysis, 25 cases of acute MI occurred on days 1-7 after influenza infection and 394 occurred during the control period.

The adjusted relative incidence of acute MI during the risk period compared with during the control period was 6.16 (95% CI, 4.11-9.24).

The relative incidence of acute MI in individuals with no previous hospitalization for coronary artery disease was 16.60 (95% CI, 10.45-26.37); for those with a previous hospital admission for coronary artery disease, the relative incidence was 1.43 (95% CI, 0.53-3.84).

A temporary increase in the risk for MI has been reported in several previous studies. A 2018 Canadian study by Kwong and colleagues showed a sixfold elevation in the risk for acute MI after influenza infection, which was subsequently confirmed in studies from the United States, Denmark, and Scotland.

In their study, Dr. Bruijning-Verhagen and colleagues aimed to further quantify the association between laboratory-confirmed influenza infection and acute MI and to look at specific subgroups that might have the potential to guide a more individualized approach to prevention.

They replicated the Canadian study using a self-controlled case-series design that corrects for time-invariant confounding and found very similar results: A sixfold increase in the risk for acute MI in the first week after laboratory-confirmed influenza infection.

“The fact that we found similar results to Kwong et al. strengthens the finding that acute flu infection is linked to increased MI risk. This is becoming more and more clear now. It also shows that this effect is generalizable to other countries,” Dr. Bruijning-Verhagen said.
 

People Without Cardiovascular Disease at Highest Risk 

The researchers moved the field ahead by also looking at whether there is a difference in risk between individuals with flu who already had cardiovascular disease and those who did not.

“Most previous studies of flu and MI didn’t stratify between individuals with and without existing cardiovascular disease. And the ones that did look at this weren’t able to show a difference with any confidence,” Dr. Bruijning-Verhagen explained. “There have been suggestions before of a higher risk of MI in individuals with acute flu infection who do not have existing known cardiovascular disease, but this was uncertain.” 

The current study showed a large difference between the two groups, with a much higher risk for MI linked to flu in individuals without any known cardiovascular disease.

“You would think patients with existing cardiovascular disease would be more at risk of MI with flu infection, so this was a surprising result,” reported Dr. Bruijning-Verhagen. “But I think the result is real. The difference between the two groups was too big for it not to be.”

Influenza can cause a hypercoagulable state, systemic inflammation, and vascular changes that can trigger MI, even in patients not thought to be at risk before, she pointed out. And this is on top of high cardiac demands because of the acute infection.

Patients who already have cardiovascular disease may be protected to some extent by the cardiovascular medications that they are taking, she added.

These results could justify the use of short-term anticoagulation in patients with severe flu infection to cover the high-risk period, Dr. Bruijning-Verhagen suggested. “We give short-term anticoagulation as prophylaxis to patients when they have surgery. This would not be that different. But obviously, this approach would have to be tested.”

Clinical studies looking at such a strategy are currently underway.
 

‘Get Your Flu Shot’

The results reinforce the need for anyone who is eligible to get the flu vaccine. “These results should give extra weight to the message to get your flu shot,” she said. “Even if you do not consider yourself someone at risk of cardiovascular disease, our study shows that you can still have an increased risk of MI as a result of severe flu infection.” 

In many countries, the flu vaccine is recommended for everyone older than 60 or 65 years and for younger people with a history of cardiovascular disease. Data on flu vaccination was not available in the current study, but the average age of patients infected with flu was 74 years, so most patients would have been eligible to receive vaccination, she said.

In the Netherlands where the research took place, flu vaccination is recommended for everyone older than 60 years, and uptake is about 60%.

“There will be some cases in younger people, but the number needed to vaccinate to show a benefit would be much larger in younger people, and that may not be cost-effective,” reported Dr. Bruijning-Verhagen.

Flu vaccination policies vary across the world, with many factors being taken into account; some countries already advocate for universal vaccination every year.
 

Extend Flu Vaccination to Prevent ACS 

This study “provides further impetus to policy makers to review and update guidelines on prevention of acute coronary syndromes,” Raina MacIntyre, MBBS, Zubair Akhtar, MPH, and Aye Moa, MPH, University of New South Wales, Sydney, Australia, wrote in an accompanying editorial.

“Although vaccination to prevent influenza is recommended and funded in many countries for people 65 years of age and older, the additional benefits of prevention of ACS [acute coronary syndromes] have not been adopted universally into policy and practice nor have recommendations considered prevention of ACS in people 50-64 years of age,” they added.

“Vaccination is low-hanging fruit for people at risk of acute myocardial infarction who have not yet had a first event. It is time that we viewed influenza vaccine as a routine preventive measure for ACS and for people with coronary artery disease risk factors, along with statins, blood pressure control, and smoking cessation,” she explained.

The question of whether the link found between elevated MI risk and severe flu infection might be the result of MI being more likely to be detected in patients hospitalized with severe flu infection, who would undergo a thorough workup, was raised in a second editorial by Lori E. Dodd, PhD, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.

“I think this would be very unlikely to account for the large effect we found,” responded Dr. Bruijning-Verhagen. “There may be the occasional silent MI that gets missed in patients who are not hospitalized, but, in general, acute MI is not something that goes undetected.”

A version of this article appeared on Medscape.com.

The link between influenza infection and a rise in short-term risk for acute myocardial infarction (MI) has been reaffirmed in a new study, which showed the risk appears to be particularly elevated in individuals with no prior diagnosis of coronary artery disease.

“Our study results confirm previous findings of an increased risk of MI during or immediately following acute severe flu infection and raises the idea of giving prophylactic anticoagulation to these patients,” reported Patricia Bruijning-Verhagen, MD, University Medical Center Utrecht, the Netherlands, who is the senior author of the study, which was published online in NEJM Evidence.

“Our results also change things — in that we now know the focus should be on people without a history of cardiovascular disease — and highlight the importance of flu vaccination, particularly for this group,” she pointed out.

The observational, self-controlled, case-series study linked laboratory records on respiratory virus polymerase chain reaction (PCR) testing from 16 laboratories in the Netherlands to national mortality, hospitalization, medication, and administrative registries. Investigators compared the incidence of acute MI during the risk period — days 1-7 after influenza infection — with that in the control period — 1 year before and 51 weeks after the risk period.

The researchers found 26,221 positive PCR tests for influenza, constituting 23,405 unique influenza illness episodes. Of the episodes of acute MI occurring in the year before or the year after confirmed influenza infection and included in the analysis, 25 cases of acute MI occurred on days 1-7 after influenza infection and 394 occurred during the control period.

The adjusted relative incidence of acute MI during the risk period compared with during the control period was 6.16 (95% CI, 4.11-9.24).

The relative incidence of acute MI in individuals with no previous hospitalization for coronary artery disease was 16.60 (95% CI, 10.45-26.37); for those with a previous hospital admission for coronary artery disease, the relative incidence was 1.43 (95% CI, 0.53-3.84).

A temporary increase in the risk for MI has been reported in several previous studies. A 2018 Canadian study by Kwong and colleagues showed a sixfold elevation in the risk for acute MI after influenza infection, which was subsequently confirmed in studies from the United States, Denmark, and Scotland.

In their study, Dr. Bruijning-Verhagen and colleagues aimed to further quantify the association between laboratory-confirmed influenza infection and acute MI and to look at specific subgroups that might have the potential to guide a more individualized approach to prevention.

They replicated the Canadian study using a self-controlled case-series design that corrects for time-invariant confounding and found very similar results: A sixfold increase in the risk for acute MI in the first week after laboratory-confirmed influenza infection.

“The fact that we found similar results to Kwong et al. strengthens the finding that acute flu infection is linked to increased MI risk. This is becoming more and more clear now. It also shows that this effect is generalizable to other countries,” Dr. Bruijning-Verhagen said.
 

People Without Cardiovascular Disease at Highest Risk 

The researchers moved the field ahead by also looking at whether there is a difference in risk between individuals with flu who already had cardiovascular disease and those who did not.

“Most previous studies of flu and MI didn’t stratify between individuals with and without existing cardiovascular disease. And the ones that did look at this weren’t able to show a difference with any confidence,” Dr. Bruijning-Verhagen explained. “There have been suggestions before of a higher risk of MI in individuals with acute flu infection who do not have existing known cardiovascular disease, but this was uncertain.” 

The current study showed a large difference between the two groups, with a much higher risk for MI linked to flu in individuals without any known cardiovascular disease.

“You would think patients with existing cardiovascular disease would be more at risk of MI with flu infection, so this was a surprising result,” reported Dr. Bruijning-Verhagen. “But I think the result is real. The difference between the two groups was too big for it not to be.”

Influenza can cause a hypercoagulable state, systemic inflammation, and vascular changes that can trigger MI, even in patients not thought to be at risk before, she pointed out. And this is on top of high cardiac demands because of the acute infection.

Patients who already have cardiovascular disease may be protected to some extent by the cardiovascular medications that they are taking, she added.

These results could justify the use of short-term anticoagulation in patients with severe flu infection to cover the high-risk period, Dr. Bruijning-Verhagen suggested. “We give short-term anticoagulation as prophylaxis to patients when they have surgery. This would not be that different. But obviously, this approach would have to be tested.”

Clinical studies looking at such a strategy are currently underway.
 

‘Get Your Flu Shot’

The results reinforce the need for anyone who is eligible to get the flu vaccine. “These results should give extra weight to the message to get your flu shot,” she said. “Even if you do not consider yourself someone at risk of cardiovascular disease, our study shows that you can still have an increased risk of MI as a result of severe flu infection.” 

In many countries, the flu vaccine is recommended for everyone older than 60 or 65 years and for younger people with a history of cardiovascular disease. Data on flu vaccination was not available in the current study, but the average age of patients infected with flu was 74 years, so most patients would have been eligible to receive vaccination, she said.

In the Netherlands where the research took place, flu vaccination is recommended for everyone older than 60 years, and uptake is about 60%.

“There will be some cases in younger people, but the number needed to vaccinate to show a benefit would be much larger in younger people, and that may not be cost-effective,” reported Dr. Bruijning-Verhagen.

Flu vaccination policies vary across the world, with many factors being taken into account; some countries already advocate for universal vaccination every year.
 

Extend Flu Vaccination to Prevent ACS 

This study “provides further impetus to policy makers to review and update guidelines on prevention of acute coronary syndromes,” Raina MacIntyre, MBBS, Zubair Akhtar, MPH, and Aye Moa, MPH, University of New South Wales, Sydney, Australia, wrote in an accompanying editorial.

“Although vaccination to prevent influenza is recommended and funded in many countries for people 65 years of age and older, the additional benefits of prevention of ACS [acute coronary syndromes] have not been adopted universally into policy and practice nor have recommendations considered prevention of ACS in people 50-64 years of age,” they added.

“Vaccination is low-hanging fruit for people at risk of acute myocardial infarction who have not yet had a first event. It is time that we viewed influenza vaccine as a routine preventive measure for ACS and for people with coronary artery disease risk factors, along with statins, blood pressure control, and smoking cessation,” she explained.

The question of whether the link found between elevated MI risk and severe flu infection might be the result of MI being more likely to be detected in patients hospitalized with severe flu infection, who would undergo a thorough workup, was raised in a second editorial by Lori E. Dodd, PhD, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.

“I think this would be very unlikely to account for the large effect we found,” responded Dr. Bruijning-Verhagen. “There may be the occasional silent MI that gets missed in patients who are not hospitalized, but, in general, acute MI is not something that goes undetected.”

A version of this article appeared on Medscape.com.

The link between influenza infection and a rise in short-term risk for acute myocardial infarction (MI) has been reaffirmed in a new study, which showed the risk appears to be particularly elevated in individuals with no prior diagnosis of coronary artery disease.

“Our study results confirm previous findings of an increased risk of MI during or immediately following acute severe flu infection and raises the idea of giving prophylactic anticoagulation to these patients,” reported Patricia Bruijning-Verhagen, MD, University Medical Center Utrecht, the Netherlands, who is the senior author of the study, which was published online in NEJM Evidence.

“Our results also change things — in that we now know the focus should be on people without a history of cardiovascular disease — and highlight the importance of flu vaccination, particularly for this group,” she pointed out.

The observational, self-controlled, case-series study linked laboratory records on respiratory virus polymerase chain reaction (PCR) testing from 16 laboratories in the Netherlands to national mortality, hospitalization, medication, and administrative registries. Investigators compared the incidence of acute MI during the risk period — days 1-7 after influenza infection — with that in the control period — 1 year before and 51 weeks after the risk period.

The researchers found 26,221 positive PCR tests for influenza, constituting 23,405 unique influenza illness episodes. Of the episodes of acute MI occurring in the year before or the year after confirmed influenza infection and included in the analysis, 25 cases of acute MI occurred on days 1-7 after influenza infection and 394 occurred during the control period.

The adjusted relative incidence of acute MI during the risk period compared with during the control period was 6.16 (95% CI, 4.11-9.24).

The relative incidence of acute MI in individuals with no previous hospitalization for coronary artery disease was 16.60 (95% CI, 10.45-26.37); for those with a previous hospital admission for coronary artery disease, the relative incidence was 1.43 (95% CI, 0.53-3.84).

A temporary increase in the risk for MI has been reported in several previous studies. A 2018 Canadian study by Kwong and colleagues showed a sixfold elevation in the risk for acute MI after influenza infection, which was subsequently confirmed in studies from the United States, Denmark, and Scotland.

In their study, Dr. Bruijning-Verhagen and colleagues aimed to further quantify the association between laboratory-confirmed influenza infection and acute MI and to look at specific subgroups that might have the potential to guide a more individualized approach to prevention.

They replicated the Canadian study using a self-controlled case-series design that corrects for time-invariant confounding and found very similar results: A sixfold increase in the risk for acute MI in the first week after laboratory-confirmed influenza infection.

“The fact that we found similar results to Kwong et al. strengthens the finding that acute flu infection is linked to increased MI risk. This is becoming more and more clear now. It also shows that this effect is generalizable to other countries,” Dr. Bruijning-Verhagen said.
 

People Without Cardiovascular Disease at Highest Risk 

The researchers moved the field ahead by also looking at whether there is a difference in risk between individuals with flu who already had cardiovascular disease and those who did not.

“Most previous studies of flu and MI didn’t stratify between individuals with and without existing cardiovascular disease. And the ones that did look at this weren’t able to show a difference with any confidence,” Dr. Bruijning-Verhagen explained. “There have been suggestions before of a higher risk of MI in individuals with acute flu infection who do not have existing known cardiovascular disease, but this was uncertain.” 

The current study showed a large difference between the two groups, with a much higher risk for MI linked to flu in individuals without any known cardiovascular disease.

“You would think patients with existing cardiovascular disease would be more at risk of MI with flu infection, so this was a surprising result,” reported Dr. Bruijning-Verhagen. “But I think the result is real. The difference between the two groups was too big for it not to be.”

Influenza can cause a hypercoagulable state, systemic inflammation, and vascular changes that can trigger MI, even in patients not thought to be at risk before, she pointed out. And this is on top of high cardiac demands because of the acute infection.

Patients who already have cardiovascular disease may be protected to some extent by the cardiovascular medications that they are taking, she added.

These results could justify the use of short-term anticoagulation in patients with severe flu infection to cover the high-risk period, Dr. Bruijning-Verhagen suggested. “We give short-term anticoagulation as prophylaxis to patients when they have surgery. This would not be that different. But obviously, this approach would have to be tested.”

Clinical studies looking at such a strategy are currently underway.
 

‘Get Your Flu Shot’

The results reinforce the need for anyone who is eligible to get the flu vaccine. “These results should give extra weight to the message to get your flu shot,” she said. “Even if you do not consider yourself someone at risk of cardiovascular disease, our study shows that you can still have an increased risk of MI as a result of severe flu infection.” 

In many countries, the flu vaccine is recommended for everyone older than 60 or 65 years and for younger people with a history of cardiovascular disease. Data on flu vaccination was not available in the current study, but the average age of patients infected with flu was 74 years, so most patients would have been eligible to receive vaccination, she said.

In the Netherlands where the research took place, flu vaccination is recommended for everyone older than 60 years, and uptake is about 60%.

“There will be some cases in younger people, but the number needed to vaccinate to show a benefit would be much larger in younger people, and that may not be cost-effective,” reported Dr. Bruijning-Verhagen.

Flu vaccination policies vary across the world, with many factors being taken into account; some countries already advocate for universal vaccination every year.
 

Extend Flu Vaccination to Prevent ACS 

This study “provides further impetus to policy makers to review and update guidelines on prevention of acute coronary syndromes,” Raina MacIntyre, MBBS, Zubair Akhtar, MPH, and Aye Moa, MPH, University of New South Wales, Sydney, Australia, wrote in an accompanying editorial.

“Although vaccination to prevent influenza is recommended and funded in many countries for people 65 years of age and older, the additional benefits of prevention of ACS [acute coronary syndromes] have not been adopted universally into policy and practice nor have recommendations considered prevention of ACS in people 50-64 years of age,” they added.

“Vaccination is low-hanging fruit for people at risk of acute myocardial infarction who have not yet had a first event. It is time that we viewed influenza vaccine as a routine preventive measure for ACS and for people with coronary artery disease risk factors, along with statins, blood pressure control, and smoking cessation,” she explained.

The question of whether the link found between elevated MI risk and severe flu infection might be the result of MI being more likely to be detected in patients hospitalized with severe flu infection, who would undergo a thorough workup, was raised in a second editorial by Lori E. Dodd, PhD, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.

“I think this would be very unlikely to account for the large effect we found,” responded Dr. Bruijning-Verhagen. “There may be the occasional silent MI that gets missed in patients who are not hospitalized, but, in general, acute MI is not something that goes undetected.”

A version of this article appeared on Medscape.com.

A recent study published in JAMA Network Open described the epidemiological characteristics of respiratory syncytial virus (RSV) infection in Ontario, Canada, after the onset of the COVID-19 pandemic. It is the latest in a series of studies that suggest that virus circulation dynamics and hospitalizations have changed over time. These are crucial pieces of information for managing the seasonal epidemic.
 

News From Canada

The Canadian study compared hospitalization rates and characteristics of children aged < 5 years who were admitted to the hospital for RSV infection during three prepandemic seasons (2017-2020) and two “postpandemic” seasons (2021-2023).

Compared with the prepandemic period, the 2021-2022 RSV season peaked a little earlier (early December instead of mid-December) but had comparable hospitalization rates. The 2022-2023 season, on the other hand, peaked a month earlier with a more than doubled hospitalization rate. Hospitalizations increased from about 2000 to 4977. In 2022, hospitalizations also occurred in spring and summer. In 2022-2023, more hospitalizations than expected were observed, especially in the 24-59–month-old group.

The percentage of patients hospitalized in intensive care units (ICUs) increased (11.4% in 2021-2022 and 13.9% in 2022-2023 compared with 9.8% in 2017-2018), and the ICU hospitalization rate tripled compared with the prepandemic period. No differences were observed in ICU length of stay or severe outcomes (such as use of extracorporeal membrane oxygenation or hospital mortality). The use of mechanical ventilation increased, however.
 

News From the USA

Another recent study, published in Pediatrics, provides an overview of RSV epidemiology in the United States based on data collected from seven pediatric hospitals across the country. Data from 2021 and 2022 were compared with those from four prepandemic seasons (2016-2020).

Most observations agree with what was reported in the Canadian study. In the four prepandemic years, the peak of RSV-associated hospitalizations was recorded in December-January. In 2021, it was in July, and in 2022, it was in November. Hospitalization rates of RSV-positive patients in 2021 and 2022 were higher than those in the prepandemic period. In 2022, compared with 2021, the hospitalization rate of children aged < 2 years did not change, while that of children aged 24-59 months increased significantly.

In 2022, the percentage of children requiring oxygen therapy was higher. But unlike in the other study, the percentage of children undergoing mechanical ventilation or those hospitalized in ICUs was not significantly different from the past. It is worth noting that in 2022, multiple respiratory coinfections were more frequently found in RSV-positive hospitalized children.
 

News From Italy

“In our experience, as well, the epidemiology of RSV has shown changes following the pandemic,” Marta Luisa Ciofi degli Atti, MD, head of the Epidemiology, Clinical Pathways, and Clinical Risk Complex Operating Unit at the Bambino Gesù Pediatric Hospital in Rome, Italy, told Univadis Italy. “Before the pandemic, RSV infection peaks were regularly in late December-January. The pandemic, with its containment measures, interrupted the typical seasonality of RSV: A season was skipped, and in 2021, there was a season that was different from all previous ones because it was anticipated, with a peak in October-November and a much higher incidence. In 2022, we also had a higher autumn incidence compared with the past, with a peak in November. However, the number of confirmed infections approached prepandemic levels. The season was also anticipated in 2023, so prepandemic epidemiology does not seem to have stabilized yet.”

As did Canada and the USA, Italy had an increase in incidence among older children in 2022. “Cases of children aged 1-4 years increased from 24% in 2018 to 30%, and those of children aged 5-9 years from 5.4% to 8.7%,” said Dr. Ciofi degli Atti. “Children in the first year of life were similarly affected in the pre- and postpandemic periods, while cases increased among older children. It is as if there has been an accumulation of susceptible patients: Children who did not get sick in the first year of life during the pandemic and got sick later in the postpandemic period.”
 

Predicting (and Preventing) Chaos

As described in an article recently published in the Italian Journal of Pediatrics, Dr. Ciofi degli Atti worked on a model to predict the peak of RSV infections. “It is a mathematical predictive model that, based on observations in a certain number of seasons, allows the estimation of expectations,” she explained. It is challenging to develop a model when there are highly disruptive events such as a pandemic, she added, but these situations make predictive tools of the utmost interest. “The predictive capacity for the 2023 season was good: We had predicted that the peak would be reached in week 49, and indeed, the peak was observed in December.”

The study’s authors noted that in the years considered, the seasonal peak of RSV infections always occurred 4-5 weeks after the week in which the number of hospitalizations doubled or tripled. “It is a curve that rises very rapidly,” said the epidemiologist.

“RSV infection causes severe clinical conditions that affect young children who may need hospitalization and sometimes respiratory assistance. The epidemic peaks within a few weeks and has a disruptive effect on healthcare organization,” said Dr. Ciofi degli Atti. “Preventive vaccination is a huge opportunity in terms of health benefits for young children, who are directly involved, and also to reduce the impact that seasonal RSV epidemics have on hospital pathways. At the national and regional levels, work is therefore underway to start vaccination to prevent the circulation of this virus.”
 

This story was translated from Univadis Italy, which is part of the Medscape Professional Network, using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

A recent study published in JAMA Network Open described the epidemiological characteristics of respiratory syncytial virus (RSV) infection in Ontario, Canada, after the onset of the COVID-19 pandemic. It is the latest in a series of studies that suggest that virus circulation dynamics and hospitalizations have changed over time. These are crucial pieces of information for managing the seasonal epidemic.
 

News From Canada

The Canadian study compared hospitalization rates and characteristics of children aged < 5 years who were admitted to the hospital for RSV infection during three prepandemic seasons (2017-2020) and two “postpandemic” seasons (2021-2023).

Compared with the prepandemic period, the 2021-2022 RSV season peaked a little earlier (early December instead of mid-December) but had comparable hospitalization rates. The 2022-2023 season, on the other hand, peaked a month earlier with a more than doubled hospitalization rate. Hospitalizations increased from about 2000 to 4977. In 2022, hospitalizations also occurred in spring and summer. In 2022-2023, more hospitalizations than expected were observed, especially in the 24-59–month-old group.

The percentage of patients hospitalized in intensive care units (ICUs) increased (11.4% in 2021-2022 and 13.9% in 2022-2023 compared with 9.8% in 2017-2018), and the ICU hospitalization rate tripled compared with the prepandemic period. No differences were observed in ICU length of stay or severe outcomes (such as use of extracorporeal membrane oxygenation or hospital mortality). The use of mechanical ventilation increased, however.
 

News From the USA

Another recent study, published in Pediatrics, provides an overview of RSV epidemiology in the United States based on data collected from seven pediatric hospitals across the country. Data from 2021 and 2022 were compared with those from four prepandemic seasons (2016-2020).

Most observations agree with what was reported in the Canadian study. In the four prepandemic years, the peak of RSV-associated hospitalizations was recorded in December-January. In 2021, it was in July, and in 2022, it was in November. Hospitalization rates of RSV-positive patients in 2021 and 2022 were higher than those in the prepandemic period. In 2022, compared with 2021, the hospitalization rate of children aged < 2 years did not change, while that of children aged 24-59 months increased significantly.

In 2022, the percentage of children requiring oxygen therapy was higher. But unlike in the other study, the percentage of children undergoing mechanical ventilation or those hospitalized in ICUs was not significantly different from the past. It is worth noting that in 2022, multiple respiratory coinfections were more frequently found in RSV-positive hospitalized children.
 

News From Italy

“In our experience, as well, the epidemiology of RSV has shown changes following the pandemic,” Marta Luisa Ciofi degli Atti, MD, head of the Epidemiology, Clinical Pathways, and Clinical Risk Complex Operating Unit at the Bambino Gesù Pediatric Hospital in Rome, Italy, told Univadis Italy. “Before the pandemic, RSV infection peaks were regularly in late December-January. The pandemic, with its containment measures, interrupted the typical seasonality of RSV: A season was skipped, and in 2021, there was a season that was different from all previous ones because it was anticipated, with a peak in October-November and a much higher incidence. In 2022, we also had a higher autumn incidence compared with the past, with a peak in November. However, the number of confirmed infections approached prepandemic levels. The season was also anticipated in 2023, so prepandemic epidemiology does not seem to have stabilized yet.”

As did Canada and the USA, Italy had an increase in incidence among older children in 2022. “Cases of children aged 1-4 years increased from 24% in 2018 to 30%, and those of children aged 5-9 years from 5.4% to 8.7%,” said Dr. Ciofi degli Atti. “Children in the first year of life were similarly affected in the pre- and postpandemic periods, while cases increased among older children. It is as if there has been an accumulation of susceptible patients: Children who did not get sick in the first year of life during the pandemic and got sick later in the postpandemic period.”
 

Predicting (and Preventing) Chaos

As described in an article recently published in the Italian Journal of Pediatrics, Dr. Ciofi degli Atti worked on a model to predict the peak of RSV infections. “It is a mathematical predictive model that, based on observations in a certain number of seasons, allows the estimation of expectations,” she explained. It is challenging to develop a model when there are highly disruptive events such as a pandemic, she added, but these situations make predictive tools of the utmost interest. “The predictive capacity for the 2023 season was good: We had predicted that the peak would be reached in week 49, and indeed, the peak was observed in December.”

The study’s authors noted that in the years considered, the seasonal peak of RSV infections always occurred 4-5 weeks after the week in which the number of hospitalizations doubled or tripled. “It is a curve that rises very rapidly,” said the epidemiologist.

“RSV infection causes severe clinical conditions that affect young children who may need hospitalization and sometimes respiratory assistance. The epidemic peaks within a few weeks and has a disruptive effect on healthcare organization,” said Dr. Ciofi degli Atti. “Preventive vaccination is a huge opportunity in terms of health benefits for young children, who are directly involved, and also to reduce the impact that seasonal RSV epidemics have on hospital pathways. At the national and regional levels, work is therefore underway to start vaccination to prevent the circulation of this virus.”
 

This story was translated from Univadis Italy, which is part of the Medscape Professional Network, using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

A recent study published in JAMA Network Open described the epidemiological characteristics of respiratory syncytial virus (RSV) infection in Ontario, Canada, after the onset of the COVID-19 pandemic. It is the latest in a series of studies that suggest that virus circulation dynamics and hospitalizations have changed over time. These are crucial pieces of information for managing the seasonal epidemic.
 

News From Canada

The Canadian study compared hospitalization rates and characteristics of children aged < 5 years who were admitted to the hospital for RSV infection during three prepandemic seasons (2017-2020) and two “postpandemic” seasons (2021-2023).

Compared with the prepandemic period, the 2021-2022 RSV season peaked a little earlier (early December instead of mid-December) but had comparable hospitalization rates. The 2022-2023 season, on the other hand, peaked a month earlier with a more than doubled hospitalization rate. Hospitalizations increased from about 2000 to 4977. In 2022, hospitalizations also occurred in spring and summer. In 2022-2023, more hospitalizations than expected were observed, especially in the 24-59–month-old group.

The percentage of patients hospitalized in intensive care units (ICUs) increased (11.4% in 2021-2022 and 13.9% in 2022-2023 compared with 9.8% in 2017-2018), and the ICU hospitalization rate tripled compared with the prepandemic period. No differences were observed in ICU length of stay or severe outcomes (such as use of extracorporeal membrane oxygenation or hospital mortality). The use of mechanical ventilation increased, however.
 

News From the USA

Another recent study, published in Pediatrics, provides an overview of RSV epidemiology in the United States based on data collected from seven pediatric hospitals across the country. Data from 2021 and 2022 were compared with those from four prepandemic seasons (2016-2020).

Most observations agree with what was reported in the Canadian study. In the four prepandemic years, the peak of RSV-associated hospitalizations was recorded in December-January. In 2021, it was in July, and in 2022, it was in November. Hospitalization rates of RSV-positive patients in 2021 and 2022 were higher than those in the prepandemic period. In 2022, compared with 2021, the hospitalization rate of children aged < 2 years did not change, while that of children aged 24-59 months increased significantly.

In 2022, the percentage of children requiring oxygen therapy was higher. But unlike in the other study, the percentage of children undergoing mechanical ventilation or those hospitalized in ICUs was not significantly different from the past. It is worth noting that in 2022, multiple respiratory coinfections were more frequently found in RSV-positive hospitalized children.
 

News From Italy

“In our experience, as well, the epidemiology of RSV has shown changes following the pandemic,” Marta Luisa Ciofi degli Atti, MD, head of the Epidemiology, Clinical Pathways, and Clinical Risk Complex Operating Unit at the Bambino Gesù Pediatric Hospital in Rome, Italy, told Univadis Italy. “Before the pandemic, RSV infection peaks were regularly in late December-January. The pandemic, with its containment measures, interrupted the typical seasonality of RSV: A season was skipped, and in 2021, there was a season that was different from all previous ones because it was anticipated, with a peak in October-November and a much higher incidence. In 2022, we also had a higher autumn incidence compared with the past, with a peak in November. However, the number of confirmed infections approached prepandemic levels. The season was also anticipated in 2023, so prepandemic epidemiology does not seem to have stabilized yet.”

As did Canada and the USA, Italy had an increase in incidence among older children in 2022. “Cases of children aged 1-4 years increased from 24% in 2018 to 30%, and those of children aged 5-9 years from 5.4% to 8.7%,” said Dr. Ciofi degli Atti. “Children in the first year of life were similarly affected in the pre- and postpandemic periods, while cases increased among older children. It is as if there has been an accumulation of susceptible patients: Children who did not get sick in the first year of life during the pandemic and got sick later in the postpandemic period.”
 

Predicting (and Preventing) Chaos

As described in an article recently published in the Italian Journal of Pediatrics, Dr. Ciofi degli Atti worked on a model to predict the peak of RSV infections. “It is a mathematical predictive model that, based on observations in a certain number of seasons, allows the estimation of expectations,” she explained. It is challenging to develop a model when there are highly disruptive events such as a pandemic, she added, but these situations make predictive tools of the utmost interest. “The predictive capacity for the 2023 season was good: We had predicted that the peak would be reached in week 49, and indeed, the peak was observed in December.”

The study’s authors noted that in the years considered, the seasonal peak of RSV infections always occurred 4-5 weeks after the week in which the number of hospitalizations doubled or tripled. “It is a curve that rises very rapidly,” said the epidemiologist.

“RSV infection causes severe clinical conditions that affect young children who may need hospitalization and sometimes respiratory assistance. The epidemic peaks within a few weeks and has a disruptive effect on healthcare organization,” said Dr. Ciofi degli Atti. “Preventive vaccination is a huge opportunity in terms of health benefits for young children, who are directly involved, and also to reduce the impact that seasonal RSV epidemics have on hospital pathways. At the national and regional levels, work is therefore underway to start vaccination to prevent the circulation of this virus.”
 

This story was translated from Univadis Italy, which is part of the Medscape Professional Network, using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

People who have recovered from long COVID can suffer relapses or flare-ups from new viral infections — not just from COVID but from cold, flu, and other viral pathogens, researchers have found.

In some cases, they may be experiencing what researchers call viral interference, something also experienced by people with HIV and other infections associated with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Clinical studies on the issue are limited, but patients, doctors, and researchers report many people who previously had long COVID have developed recurring symptoms after consequent viral infections.

Viral persistence — where bits of virus linger in the body — and viral reactivation remain two of the leading suspects for Yale researchers. Viral activation occurs when the immune system responds to an infection by triggering a dormant virus.

Anecdotally, these flare-ups occur more commonly in patients with long COVID with autonomic dysfunction — severe dizziness when standing up — and other symptoms of ME/CFS, said Alba Azola, MD, a Johns Hopkins Medicine rehabilitation specialist in Baltimore, Maryland, who works with patients with long COVID and other “fatiguing illnesses.”

At last count, about 18% of those surveyed by the Centers for Disease Control and Prevention said they had experienced long COVID. Nearly 60% of those surveyed said they had contracted COVID-19 at least once.

Dr. Azola said that very afternoon she had seen a patient with the flu and a recurrence of previous long COVID symptoms. Not much data exist about cases like this.

“I can’t say there is a specific study looking at this, but anecdotally, we see it all the time,” Dr. Azola said.

She has not seen completely different symptoms; more commonly, she sees a flare-up of previously existing symptoms.

David Putrino, PhD, is director of rehabilitation innovation for the Mount Sinai Health System in New York City. He treats and studies patients with long COVID and echoes what others have seen.

Patients can “recover (or feel recovered) from long COVID until the next immune challenge — another COVID infection, flu infection, pregnancy, food poisoning (all examples we have seen in the clinic) — and experience a significant flare-up of your initial COVID infection,” he said.

“Relapse” is a better term than reinfection, said Jeffrey Parsonnet, MD, an infectious diseases specialist and director of the Dartmouth Hitchcock Post-Acute COVID Syndrome Clinic, Lebanon, New Hampshire.

“We see patients who had COVID-19 followed by long COVID who then get better — either completely or mostly better. Then they’ve gotten COVID again, and this is followed by recurrence of long COVID symptoms,” he said.

“Every patient looks different in terms of what gets better and how quickly. And again, some patients are not better (or even minimally so) after a couple of years,” he said.
 

Patients Tell Their Stories

On the COVID-19 Long Haulers Support Facebook group, many of the 100,000 followers ask about viral reactivation. Delainne “Laney” Bond, RN, who has battled postinfection chronic illness herself, runs the Facebook group. From what she sees, “each time a person is infected or reinfected with SARS-CoV-2, they have a risk of developing long COVID or experiencing worse long COVID. Multiple infections can lead to progressive health complications.”

The posts on her site include many queries about reinfections. A post from December included nearly 80 comments with people describing the full range of symptoms. Some stories relayed how the reinfection symptoms were short lived. Some report returning to their baseline — not completely symptom free but improved.

Doctors and patients say long COVID comes and goes — relapsing-remitting — and shares many features with other complex multisystem chronic conditions, according to a new National Academy of Sciences report. Those include ME/CFS and the Epstein-Barr virus.

As far as how to treat, Dr. Putrino is one of the clinical researchers testing antivirals. One is Paxlovid; the others are drugs developed for the AIDS virus.

“A plausible mechanism for long COVID is persistence of the SARS-CoV-2 virus in tissue and/or the reactivation of latent pathogens,” according to an explanation of the research on the PolyBio Institute website, which is involved with the research.

In the meantime, “long COVID appears to be a chronic condition with few patients achieving full remission,” according to a new Academy of Sciences report. The report concludes that long COVID recovery can plateau at 6-12 months. They also note that 18%-22% of people who have long COVID symptoms at 5 months are still ill at 1 year.

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

People who have recovered from long COVID can suffer relapses or flare-ups from new viral infections — not just from COVID but from cold, flu, and other viral pathogens, researchers have found.

In some cases, they may be experiencing what researchers call viral interference, something also experienced by people with HIV and other infections associated with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Clinical studies on the issue are limited, but patients, doctors, and researchers report many people who previously had long COVID have developed recurring symptoms after consequent viral infections.

Viral persistence — where bits of virus linger in the body — and viral reactivation remain two of the leading suspects for Yale researchers. Viral activation occurs when the immune system responds to an infection by triggering a dormant virus.

Anecdotally, these flare-ups occur more commonly in patients with long COVID with autonomic dysfunction — severe dizziness when standing up — and other symptoms of ME/CFS, said Alba Azola, MD, a Johns Hopkins Medicine rehabilitation specialist in Baltimore, Maryland, who works with patients with long COVID and other “fatiguing illnesses.”

At last count, about 18% of those surveyed by the Centers for Disease Control and Prevention said they had experienced long COVID. Nearly 60% of those surveyed said they had contracted COVID-19 at least once.

Dr. Azola said that very afternoon she had seen a patient with the flu and a recurrence of previous long COVID symptoms. Not much data exist about cases like this.

“I can’t say there is a specific study looking at this, but anecdotally, we see it all the time,” Dr. Azola said.

She has not seen completely different symptoms; more commonly, she sees a flare-up of previously existing symptoms.

David Putrino, PhD, is director of rehabilitation innovation for the Mount Sinai Health System in New York City. He treats and studies patients with long COVID and echoes what others have seen.

Patients can “recover (or feel recovered) from long COVID until the next immune challenge — another COVID infection, flu infection, pregnancy, food poisoning (all examples we have seen in the clinic) — and experience a significant flare-up of your initial COVID infection,” he said.

“Relapse” is a better term than reinfection, said Jeffrey Parsonnet, MD, an infectious diseases specialist and director of the Dartmouth Hitchcock Post-Acute COVID Syndrome Clinic, Lebanon, New Hampshire.

“We see patients who had COVID-19 followed by long COVID who then get better — either completely or mostly better. Then they’ve gotten COVID again, and this is followed by recurrence of long COVID symptoms,” he said.

“Every patient looks different in terms of what gets better and how quickly. And again, some patients are not better (or even minimally so) after a couple of years,” he said.
 

Patients Tell Their Stories

On the COVID-19 Long Haulers Support Facebook group, many of the 100,000 followers ask about viral reactivation. Delainne “Laney” Bond, RN, who has battled postinfection chronic illness herself, runs the Facebook group. From what she sees, “each time a person is infected or reinfected with SARS-CoV-2, they have a risk of developing long COVID or experiencing worse long COVID. Multiple infections can lead to progressive health complications.”

The posts on her site include many queries about reinfections. A post from December included nearly 80 comments with people describing the full range of symptoms. Some stories relayed how the reinfection symptoms were short lived. Some report returning to their baseline — not completely symptom free but improved.

Doctors and patients say long COVID comes and goes — relapsing-remitting — and shares many features with other complex multisystem chronic conditions, according to a new National Academy of Sciences report. Those include ME/CFS and the Epstein-Barr virus.

As far as how to treat, Dr. Putrino is one of the clinical researchers testing antivirals. One is Paxlovid; the others are drugs developed for the AIDS virus.

“A plausible mechanism for long COVID is persistence of the SARS-CoV-2 virus in tissue and/or the reactivation of latent pathogens,” according to an explanation of the research on the PolyBio Institute website, which is involved with the research.

In the meantime, “long COVID appears to be a chronic condition with few patients achieving full remission,” according to a new Academy of Sciences report. The report concludes that long COVID recovery can plateau at 6-12 months. They also note that 18%-22% of people who have long COVID symptoms at 5 months are still ill at 1 year.

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

People who have recovered from long COVID can suffer relapses or flare-ups from new viral infections — not just from COVID but from cold, flu, and other viral pathogens, researchers have found.

In some cases, they may be experiencing what researchers call viral interference, something also experienced by people with HIV and other infections associated with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Clinical studies on the issue are limited, but patients, doctors, and researchers report many people who previously had long COVID have developed recurring symptoms after consequent viral infections.

Viral persistence — where bits of virus linger in the body — and viral reactivation remain two of the leading suspects for Yale researchers. Viral activation occurs when the immune system responds to an infection by triggering a dormant virus.

Anecdotally, these flare-ups occur more commonly in patients with long COVID with autonomic dysfunction — severe dizziness when standing up — and other symptoms of ME/CFS, said Alba Azola, MD, a Johns Hopkins Medicine rehabilitation specialist in Baltimore, Maryland, who works with patients with long COVID and other “fatiguing illnesses.”

At last count, about 18% of those surveyed by the Centers for Disease Control and Prevention said they had experienced long COVID. Nearly 60% of those surveyed said they had contracted COVID-19 at least once.

Dr. Azola said that very afternoon she had seen a patient with the flu and a recurrence of previous long COVID symptoms. Not much data exist about cases like this.

“I can’t say there is a specific study looking at this, but anecdotally, we see it all the time,” Dr. Azola said.

She has not seen completely different symptoms; more commonly, she sees a flare-up of previously existing symptoms.

David Putrino, PhD, is director of rehabilitation innovation for the Mount Sinai Health System in New York City. He treats and studies patients with long COVID and echoes what others have seen.

Patients can “recover (or feel recovered) from long COVID until the next immune challenge — another COVID infection, flu infection, pregnancy, food poisoning (all examples we have seen in the clinic) — and experience a significant flare-up of your initial COVID infection,” he said.

“Relapse” is a better term than reinfection, said Jeffrey Parsonnet, MD, an infectious diseases specialist and director of the Dartmouth Hitchcock Post-Acute COVID Syndrome Clinic, Lebanon, New Hampshire.

“We see patients who had COVID-19 followed by long COVID who then get better — either completely or mostly better. Then they’ve gotten COVID again, and this is followed by recurrence of long COVID symptoms,” he said.

“Every patient looks different in terms of what gets better and how quickly. And again, some patients are not better (or even minimally so) after a couple of years,” he said.
 

Patients Tell Their Stories

On the COVID-19 Long Haulers Support Facebook group, many of the 100,000 followers ask about viral reactivation. Delainne “Laney” Bond, RN, who has battled postinfection chronic illness herself, runs the Facebook group. From what she sees, “each time a person is infected or reinfected with SARS-CoV-2, they have a risk of developing long COVID or experiencing worse long COVID. Multiple infections can lead to progressive health complications.”

The posts on her site include many queries about reinfections. A post from December included nearly 80 comments with people describing the full range of symptoms. Some stories relayed how the reinfection symptoms were short lived. Some report returning to their baseline — not completely symptom free but improved.

Doctors and patients say long COVID comes and goes — relapsing-remitting — and shares many features with other complex multisystem chronic conditions, according to a new National Academy of Sciences report. Those include ME/CFS and the Epstein-Barr virus.

As far as how to treat, Dr. Putrino is one of the clinical researchers testing antivirals. One is Paxlovid; the others are drugs developed for the AIDS virus.

“A plausible mechanism for long COVID is persistence of the SARS-CoV-2 virus in tissue and/or the reactivation of latent pathogens,” according to an explanation of the research on the PolyBio Institute website, which is involved with the research.

In the meantime, “long COVID appears to be a chronic condition with few patients achieving full remission,” according to a new Academy of Sciences report. The report concludes that long COVID recovery can plateau at 6-12 months. They also note that 18%-22% of people who have long COVID symptoms at 5 months are still ill at 1 year.

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

With avian influenza spreading quickly around the globe, the virus has more opportunities to mutate and cause problems for people. By some calculations, H5N1 bird flu is still at least two mutations away from widespread human infections, but experts warn that new flu symptoms in individuals at high risk are likely to start turning up in health systems this summer.

“There is a broad range of symptoms to be watching for,” said Vivien Dugan, PhD, director of the influenza division at the US Centers for Disease Control and Prevention (CDC). “Some of this will not be obvious or at the forefront of our minds.”

Dr. Dugan is leading the team of CDC scientists that is working with partners from the US Department of Agriculture, the US Food and Drug Administration (FDA), and state and local health departments to track and respond to the H5N1 bird flu outbreak currently sweeping through the United States.

Since 2022, avian influenza A viruses have been detected in more than 9300 wild birds in 50 states and territories and in commercial and backyard flocks.

“It’s a bad situation,” said Florian Krammer, PhD, professor of vaccinology at the Icahn School of Medicine at Mount Sinai in New York. “Globally, we’ve seen tons of exposure in cities around the world and even in the birds here in New York City where I am.”

Birds shed the virus in their saliva, mucous, and feces, so people or other animals with close, unprotected contact with infected birds or their contaminated environments can be infected. 

And for the first time in March 2024, H5N1 bird flu was reported in dairy cows. The US Department of Agriculture said that at last count, 101 dairy herds in 12 states had been infected, with several cases also found in dairy workers.
 

From Birds to Cattle and Farm Workers

The National Veterinary Services Laboratories confirmed the infections were highly pathogenic avian influenza H5N1 clade 2.3.4.4b of Eurasian lineage. Also known as the goose, Guangdong clade from China, phylogenetic analysis and epidemiology suggests a single introduction into cows followed by onward transmission.

“I was surprised when H5 was introduced to dairy cattle in this way,” Dr. Dugan said. “Influenza viruses are always surprising us and it reminds me to stay humble and keep an open mind when dealing with them.”

People rarely inhale or get sufficient virus in their eyes or mouth to get sick, Dr. Dugan said, but those in close contact with animals are still at risk for infection, which could lead to upper respiratory tract symptoms such as shortness of breath, cough, sore throat, or runny or stuffy nose.

Like with other viruses, people can also experience muscle or body aches, headache, fatigue, fever or, as was seen in farm workers, conjunctivitis.

But there are less-common symptoms too like diarrhea, nausea, and vomiting — and sometimes, even seizures.

The risk to the general public is still low, Dr. Dugan said, but authorities recommend that people working with animals wash their hands with soap and water and wear personal protective equipment that includes fluid-resistant coveralls, a waterproof apron, a safety-approved respirator, properly fitted goggles or face shield, a head or hair cover, gloves, and boots.

Dr. Dugan said that health care providers often don’t take a history of occupational exposures when a patient presents with flu. But with rising rates of bird flu in new animal hosts, “this will be an important next step.”
 

Asking Unusual Questions

This approach is not standardized on most electronic health records, so these are questions that clinicians will need to initiate themselves.

“Physicians should ask about work,” said Meghan Davis, PhD, associate professor at the Johns Hopkins Bloomberg School of Public Health in Baltimore. “If it’s not already on the radar, asking about any direct contact with dairy cows, poultry, pigs, wild birds, or wild mammals is important.”

Dr. Davis says she’s worried about a new study tracking risk factors for farm-to-farm transmission because it shows that farms testing positive for avian influenza often have workers with a family member also employed on another farm. “This suggests that we might need to be on the lookout for possible transmission within families,” she said. Now, we have to ask “not just if the person with symptoms has contact with or works on a dairy farm, milk processing plant, or slaughterhouse, but also if any family member does.”

Dr. Davis said that it’s important to bear in mind when taking these histories that there may be younger workers on farms and in slaughter and processing facilities due to exemptions or illegal work.

What is important now is to get the situation under control this season in dairy cattle, Dr. Krammer said. “This will be easier to stop in cows than humans, so this is the time to stop moving dairy cattle and start vaccinating them.”
 

Spotting New Cases

Since April 2024, there have been three human cases of avian influenza after exposure to dairy cows reported. “And what we don’t want to see this summer is an unusual human cluster of influenza. It’s important we keep a close, watchful eye for this,” Dr. Krammer said.

“Influenza viruses do very interesting things and as we head into fall and winter flu season, we don’t want new human co-infections that could cause major problems for us,” he said.

If people become mixing vessels of a seasonal cocktail of multiple viruses, that could empower H5N1 to mutate again into something more dangerous, sparking a new pandemic.

“It wasn’t all that long ago that we were asking China difficult questions about the steps Chinese authorities took to protect human lives from SARS-CoV-2 in the COVID pandemic. Now, we must ask ourselves many of these questions,” Dr. Krammer said. “We are at a crucial crossroad where we will either elude a new pandemic or see one take off, risking 10 to 20 million lives.”

There is a precedent for safely evading more trouble, Dr. Krammer pointed out. Government agencies have already been working with the poultry industry for a couple of years now. “And here, we have successfully stopped H5N1 with new regulations and policies.”

But moving from poultry farms to cattle has not been an easy transition, Dr. Dugan said. Cattle farms have no experience with bird flu or tactics to contain it with regulations, and officials too are working in new, unfamiliar terrain.

“What we have now isn’t a science problem, it’s a policy issue, and it hasn’t always been clear who is in charge,” Dr. Krammer said.

“Agencies are working together at the state, federal, and global level,” said Dr. Dugan. “We are increasing our transparency and are working to share what we know, when we know it.”

The infrastructure built during the COVID pandemic has helped teams prepare for this new crisis, Dr. Dugan said. Year-round, layered monitoring has clinical labs reporting seasonal influenza and novel cases.

“Laboratories are ready to help with testing,” Dr. Dugan said.

Specimens should be collected as soon as possible from patients with flu symptoms. A nasopharyngeal swab is recommended with a nasal swab combined with an oropharyngeal swab. If a patient has conjunctivitis with or without respiratory symptoms, both a conjunctival swab and a nasopharyngeal swab should be collected. 

People with severe respiratory disease should also have lower respiratory tract specimens collected.

Standard, contact, and airborne precautions are recommended for patients presenting for medical care who have illness consistent with influenza and recent exposure to birds or other animals.
 

Antiviral Drugs

There are four FDA-approved antivirals for influenza: Oseltamivir phosphate (available as a generic drug or by the trade name Tamiflu), zanamivir (Relenza), peramivir (Rapivab) , and baloxavir (Xofluza).

For people with suspected or confirmed avian influenza, treatment is recommended as soon as possible. 

There are no clinical trials measuring the outcome of antivirals in people infected with avian influenza. However, data from animal models and human observational studies suggest a benefit.

“We can’t afford to wait this summer,” Dr. Krammer said. “We have an opportunity right now to stop this in cows before we risk infecting more people. I hope we do.”

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

With avian influenza spreading quickly around the globe, the virus has more opportunities to mutate and cause problems for people. By some calculations, H5N1 bird flu is still at least two mutations away from widespread human infections, but experts warn that new flu symptoms in individuals at high risk are likely to start turning up in health systems this summer.

“There is a broad range of symptoms to be watching for,” said Vivien Dugan, PhD, director of the influenza division at the US Centers for Disease Control and Prevention (CDC). “Some of this will not be obvious or at the forefront of our minds.”

Dr. Dugan is leading the team of CDC scientists that is working with partners from the US Department of Agriculture, the US Food and Drug Administration (FDA), and state and local health departments to track and respond to the H5N1 bird flu outbreak currently sweeping through the United States.

Since 2022, avian influenza A viruses have been detected in more than 9300 wild birds in 50 states and territories and in commercial and backyard flocks.

“It’s a bad situation,” said Florian Krammer, PhD, professor of vaccinology at the Icahn School of Medicine at Mount Sinai in New York. “Globally, we’ve seen tons of exposure in cities around the world and even in the birds here in New York City where I am.”

Birds shed the virus in their saliva, mucous, and feces, so people or other animals with close, unprotected contact with infected birds or their contaminated environments can be infected. 

And for the first time in March 2024, H5N1 bird flu was reported in dairy cows. The US Department of Agriculture said that at last count, 101 dairy herds in 12 states had been infected, with several cases also found in dairy workers.
 

From Birds to Cattle and Farm Workers

The National Veterinary Services Laboratories confirmed the infections were highly pathogenic avian influenza H5N1 clade 2.3.4.4b of Eurasian lineage. Also known as the goose, Guangdong clade from China, phylogenetic analysis and epidemiology suggests a single introduction into cows followed by onward transmission.

“I was surprised when H5 was introduced to dairy cattle in this way,” Dr. Dugan said. “Influenza viruses are always surprising us and it reminds me to stay humble and keep an open mind when dealing with them.”

People rarely inhale or get sufficient virus in their eyes or mouth to get sick, Dr. Dugan said, but those in close contact with animals are still at risk for infection, which could lead to upper respiratory tract symptoms such as shortness of breath, cough, sore throat, or runny or stuffy nose.

Like with other viruses, people can also experience muscle or body aches, headache, fatigue, fever or, as was seen in farm workers, conjunctivitis.

But there are less-common symptoms too like diarrhea, nausea, and vomiting — and sometimes, even seizures.

The risk to the general public is still low, Dr. Dugan said, but authorities recommend that people working with animals wash their hands with soap and water and wear personal protective equipment that includes fluid-resistant coveralls, a waterproof apron, a safety-approved respirator, properly fitted goggles or face shield, a head or hair cover, gloves, and boots.

Dr. Dugan said that health care providers often don’t take a history of occupational exposures when a patient presents with flu. But with rising rates of bird flu in new animal hosts, “this will be an important next step.”
 

Asking Unusual Questions

This approach is not standardized on most electronic health records, so these are questions that clinicians will need to initiate themselves.

“Physicians should ask about work,” said Meghan Davis, PhD, associate professor at the Johns Hopkins Bloomberg School of Public Health in Baltimore. “If it’s not already on the radar, asking about any direct contact with dairy cows, poultry, pigs, wild birds, or wild mammals is important.”

Dr. Davis says she’s worried about a new study tracking risk factors for farm-to-farm transmission because it shows that farms testing positive for avian influenza often have workers with a family member also employed on another farm. “This suggests that we might need to be on the lookout for possible transmission within families,” she said. Now, we have to ask “not just if the person with symptoms has contact with or works on a dairy farm, milk processing plant, or slaughterhouse, but also if any family member does.”

Dr. Davis said that it’s important to bear in mind when taking these histories that there may be younger workers on farms and in slaughter and processing facilities due to exemptions or illegal work.

What is important now is to get the situation under control this season in dairy cattle, Dr. Krammer said. “This will be easier to stop in cows than humans, so this is the time to stop moving dairy cattle and start vaccinating them.”
 

Spotting New Cases

Since April 2024, there have been three human cases of avian influenza after exposure to dairy cows reported. “And what we don’t want to see this summer is an unusual human cluster of influenza. It’s important we keep a close, watchful eye for this,” Dr. Krammer said.

“Influenza viruses do very interesting things and as we head into fall and winter flu season, we don’t want new human co-infections that could cause major problems for us,” he said.

If people become mixing vessels of a seasonal cocktail of multiple viruses, that could empower H5N1 to mutate again into something more dangerous, sparking a new pandemic.

“It wasn’t all that long ago that we were asking China difficult questions about the steps Chinese authorities took to protect human lives from SARS-CoV-2 in the COVID pandemic. Now, we must ask ourselves many of these questions,” Dr. Krammer said. “We are at a crucial crossroad where we will either elude a new pandemic or see one take off, risking 10 to 20 million lives.”

There is a precedent for safely evading more trouble, Dr. Krammer pointed out. Government agencies have already been working with the poultry industry for a couple of years now. “And here, we have successfully stopped H5N1 with new regulations and policies.”

But moving from poultry farms to cattle has not been an easy transition, Dr. Dugan said. Cattle farms have no experience with bird flu or tactics to contain it with regulations, and officials too are working in new, unfamiliar terrain.

“What we have now isn’t a science problem, it’s a policy issue, and it hasn’t always been clear who is in charge,” Dr. Krammer said.

“Agencies are working together at the state, federal, and global level,” said Dr. Dugan. “We are increasing our transparency and are working to share what we know, when we know it.”

The infrastructure built during the COVID pandemic has helped teams prepare for this new crisis, Dr. Dugan said. Year-round, layered monitoring has clinical labs reporting seasonal influenza and novel cases.

“Laboratories are ready to help with testing,” Dr. Dugan said.

Specimens should be collected as soon as possible from patients with flu symptoms. A nasopharyngeal swab is recommended with a nasal swab combined with an oropharyngeal swab. If a patient has conjunctivitis with or without respiratory symptoms, both a conjunctival swab and a nasopharyngeal swab should be collected. 

People with severe respiratory disease should also have lower respiratory tract specimens collected.

Standard, contact, and airborne precautions are recommended for patients presenting for medical care who have illness consistent with influenza and recent exposure to birds or other animals.
 

Antiviral Drugs

There are four FDA-approved antivirals for influenza: Oseltamivir phosphate (available as a generic drug or by the trade name Tamiflu), zanamivir (Relenza), peramivir (Rapivab) , and baloxavir (Xofluza).

For people with suspected or confirmed avian influenza, treatment is recommended as soon as possible. 

There are no clinical trials measuring the outcome of antivirals in people infected with avian influenza. However, data from animal models and human observational studies suggest a benefit.

“We can’t afford to wait this summer,” Dr. Krammer said. “We have an opportunity right now to stop this in cows before we risk infecting more people. I hope we do.”

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

With avian influenza spreading quickly around the globe, the virus has more opportunities to mutate and cause problems for people. By some calculations, H5N1 bird flu is still at least two mutations away from widespread human infections, but experts warn that new flu symptoms in individuals at high risk are likely to start turning up in health systems this summer.

“There is a broad range of symptoms to be watching for,” said Vivien Dugan, PhD, director of the influenza division at the US Centers for Disease Control and Prevention (CDC). “Some of this will not be obvious or at the forefront of our minds.”

Dr. Dugan is leading the team of CDC scientists that is working with partners from the US Department of Agriculture, the US Food and Drug Administration (FDA), and state and local health departments to track and respond to the H5N1 bird flu outbreak currently sweeping through the United States.

Since 2022, avian influenza A viruses have been detected in more than 9300 wild birds in 50 states and territories and in commercial and backyard flocks.

“It’s a bad situation,” said Florian Krammer, PhD, professor of vaccinology at the Icahn School of Medicine at Mount Sinai in New York. “Globally, we’ve seen tons of exposure in cities around the world and even in the birds here in New York City where I am.”

Birds shed the virus in their saliva, mucous, and feces, so people or other animals with close, unprotected contact with infected birds or their contaminated environments can be infected. 

And for the first time in March 2024, H5N1 bird flu was reported in dairy cows. The US Department of Agriculture said that at last count, 101 dairy herds in 12 states had been infected, with several cases also found in dairy workers.
 

From Birds to Cattle and Farm Workers

The National Veterinary Services Laboratories confirmed the infections were highly pathogenic avian influenza H5N1 clade 2.3.4.4b of Eurasian lineage. Also known as the goose, Guangdong clade from China, phylogenetic analysis and epidemiology suggests a single introduction into cows followed by onward transmission.

“I was surprised when H5 was introduced to dairy cattle in this way,” Dr. Dugan said. “Influenza viruses are always surprising us and it reminds me to stay humble and keep an open mind when dealing with them.”

People rarely inhale or get sufficient virus in their eyes or mouth to get sick, Dr. Dugan said, but those in close contact with animals are still at risk for infection, which could lead to upper respiratory tract symptoms such as shortness of breath, cough, sore throat, or runny or stuffy nose.

Like with other viruses, people can also experience muscle or body aches, headache, fatigue, fever or, as was seen in farm workers, conjunctivitis.

But there are less-common symptoms too like diarrhea, nausea, and vomiting — and sometimes, even seizures.

The risk to the general public is still low, Dr. Dugan said, but authorities recommend that people working with animals wash their hands with soap and water and wear personal protective equipment that includes fluid-resistant coveralls, a waterproof apron, a safety-approved respirator, properly fitted goggles or face shield, a head or hair cover, gloves, and boots.

Dr. Dugan said that health care providers often don’t take a history of occupational exposures when a patient presents with flu. But with rising rates of bird flu in new animal hosts, “this will be an important next step.”
 

Asking Unusual Questions

This approach is not standardized on most electronic health records, so these are questions that clinicians will need to initiate themselves.

“Physicians should ask about work,” said Meghan Davis, PhD, associate professor at the Johns Hopkins Bloomberg School of Public Health in Baltimore. “If it’s not already on the radar, asking about any direct contact with dairy cows, poultry, pigs, wild birds, or wild mammals is important.”

Dr. Davis says she’s worried about a new study tracking risk factors for farm-to-farm transmission because it shows that farms testing positive for avian influenza often have workers with a family member also employed on another farm. “This suggests that we might need to be on the lookout for possible transmission within families,” she said. Now, we have to ask “not just if the person with symptoms has contact with or works on a dairy farm, milk processing plant, or slaughterhouse, but also if any family member does.”

Dr. Davis said that it’s important to bear in mind when taking these histories that there may be younger workers on farms and in slaughter and processing facilities due to exemptions or illegal work.

What is important now is to get the situation under control this season in dairy cattle, Dr. Krammer said. “This will be easier to stop in cows than humans, so this is the time to stop moving dairy cattle and start vaccinating them.”
 

Spotting New Cases

Since April 2024, there have been three human cases of avian influenza after exposure to dairy cows reported. “And what we don’t want to see this summer is an unusual human cluster of influenza. It’s important we keep a close, watchful eye for this,” Dr. Krammer said.

“Influenza viruses do very interesting things and as we head into fall and winter flu season, we don’t want new human co-infections that could cause major problems for us,” he said.

If people become mixing vessels of a seasonal cocktail of multiple viruses, that could empower H5N1 to mutate again into something more dangerous, sparking a new pandemic.

“It wasn’t all that long ago that we were asking China difficult questions about the steps Chinese authorities took to protect human lives from SARS-CoV-2 in the COVID pandemic. Now, we must ask ourselves many of these questions,” Dr. Krammer said. “We are at a crucial crossroad where we will either elude a new pandemic or see one take off, risking 10 to 20 million lives.”

There is a precedent for safely evading more trouble, Dr. Krammer pointed out. Government agencies have already been working with the poultry industry for a couple of years now. “And here, we have successfully stopped H5N1 with new regulations and policies.”

But moving from poultry farms to cattle has not been an easy transition, Dr. Dugan said. Cattle farms have no experience with bird flu or tactics to contain it with regulations, and officials too are working in new, unfamiliar terrain.

“What we have now isn’t a science problem, it’s a policy issue, and it hasn’t always been clear who is in charge,” Dr. Krammer said.

“Agencies are working together at the state, federal, and global level,” said Dr. Dugan. “We are increasing our transparency and are working to share what we know, when we know it.”

The infrastructure built during the COVID pandemic has helped teams prepare for this new crisis, Dr. Dugan said. Year-round, layered monitoring has clinical labs reporting seasonal influenza and novel cases.

“Laboratories are ready to help with testing,” Dr. Dugan said.

Specimens should be collected as soon as possible from patients with flu symptoms. A nasopharyngeal swab is recommended with a nasal swab combined with an oropharyngeal swab. If a patient has conjunctivitis with or without respiratory symptoms, both a conjunctival swab and a nasopharyngeal swab should be collected. 

People with severe respiratory disease should also have lower respiratory tract specimens collected.

Standard, contact, and airborne precautions are recommended for patients presenting for medical care who have illness consistent with influenza and recent exposure to birds or other animals.
 

Antiviral Drugs

There are four FDA-approved antivirals for influenza: Oseltamivir phosphate (available as a generic drug or by the trade name Tamiflu), zanamivir (Relenza), peramivir (Rapivab) , and baloxavir (Xofluza).

For people with suspected or confirmed avian influenza, treatment is recommended as soon as possible. 

There are no clinical trials measuring the outcome of antivirals in people infected with avian influenza. However, data from animal models and human observational studies suggest a benefit.

“We can’t afford to wait this summer,” Dr. Krammer said. “We have an opportunity right now to stop this in cows before we risk infecting more people. I hope we do.”

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