Media Advisory
Tuesday December 31, 2024
Balancing increased vigilance and maintaining the status quo.
What
The highly pathogenic H5N1 avian influenza A virus (H5N1 HPAI) remains a low risk to the general public, and public health experts in the United States believe that available treatments and vaccines, as well as those under development, are sufficient to prevent serious illness. However, the National Institutes of Health (NIH) and its federal partners remain focused on monitoring the virus and assessing changes, according to top officials at the National Institute of Allergy and Infectious Diseases (NIAID), which is part from the NIH.
In a comment published in the New England Journal of Medicine, NIAID Director Jeanne M. Marrazzo, MD, MPH, and Michael G. Ison, MD, MS, chief of the Respiratory Diseases Branch in NIAID’s Division of Microbiology and Infectious Diseases, say people should find a balance between increased vigilance and “the status quo”. » regarding HPAI H5N1.
Since 1996, HPAI H5N1 influenza viruses have circulated in at least 23 countries. In late 2021, HPAI H5N1 spread from Europe to North America, causing sporadic infections among wild birds and poultry farms. In 2022, the virus spread to South America where it devastated birds and marine mammals. In March 2024, USDA scientists identified HPAI H5N1 in dairy cows in the United States, which subsequently reached herds in 16 states. The virus has been detected in dairy herds in three states in the past 30 days, according to USDA/APHIS. In 2024, the virus has caused 66 confirmed and 7 probable cases of influenza in people in the United States and one case in Canada. These human cases were caused by either the H5N1 type circulating in birds (D1.1) or the type circulating in dairy cows (B3.13).
In this context, Drs. Marrazzo and Ison say there are four keys to controlling the current outbreak. The first imperative is rapid and effective collaboration among researchers in human and veterinary medicine, public health, healthcare, and professional workers, such as dairy and poultry workers.
This involves cultivating trust not only between many entities, but also with people seeking care for symptoms of concern, including conjunctivitis, the authors write. Fortunately, so far, most cases of H5N1 HPAI in the United States have been mild and resolved on their own without requiring treatment.
Their second key is to focus on the Canadian HPAI H5N1 patient, who developed respiratory failure and required medical intervention and life-saving treatment before recovering. The authors write that the mutations found in the virus in this patient highlight an urgent need for vigilant disease surveillance to identify and evaluate viral changes to assess the risk of person-to-person transmission. . They say effective surveillance requires that comprehensive genomic sequencing data from animals and humans be quickly and easily available.
Without information about where and when isolates were collected, the data cannot be linked phylogenetically to other reported sequences, limiting understanding of how the virus spreads, they write. These data would also provide the opportunity to rapidly detect mutations that could portend avidity for the human respiratory epithelium, which could require as little as a mutation of the virus.
Third, researchers must continue to develop and test medical countermeasures – such as vaccines and therapies that eliminate or mitigate disease – against H5N1 and other influenza viruses. Fortunately, current vaccine candidates neutralize circulating strains, which so far are susceptible to antivirals that may mitigate disease transmission and severity, they write.
Finally, Drs. Marrazzo and Ison encourage people to take precautions to prevent exposure to the virus and minimize the risk of infection. For example, people who work with poultry and cows should use personal protective equipment and learn about occupational hazards when working with birds and mammals, as the CDC and USDA have recommended to several times.
Ideally, following these four steps will help scientists and public health officials investigating H5N1 HPAI more quickly answer the many remaining questions about how the virus spreads, evolves, and affects people, other mammals, and the birds.
Article
M Ison and J Marrazzo. The emerging threat of H5N1 to human health. NEJM DOI: 10.1056/NEJMe2416323 (2024).
WHO
NIAID Director Jeanne M. Marrazzo, MD, MPH, and Michael G. Ison, MD, MS, chief of the Respiratory Diseases Branch in NIAID’s Division of Microbiology and Infectious Diseases, are available for comment.
Contact
To schedule interviews, please contact Ken Pekoc, (301) 402-1663, kpekoc@niaid.nih.gov.
NIAID conducts and supports research – at the NIH, across the United States and around the world – to study the causes of infectious and immune-mediated diseases and to develop better ways to prevent, diagnose and treat these diseases. Press releases, fact sheets, and other NIAID-related materials are available at NIAID website.
About the National Institutes of Health (NIH):The NIH, the nation’s medical research agency, is comprised of 27 institutes and centers and is part of the U.S. Department of Health and Human Services. The NIH is the primary federal agency that conducts and supports basic, clinical, and translational medical research, and studies the causes, treatments, and cures for common and rare diseases. For more information about the NIH and its programs, visit www.nih.gov.
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