The Centers for Disease Control and Prevention (CDC) recently released a new risk assessment regarding the H5N1 bird flu virus found in dairy cows. The assessment, conducted using the CDC’s influenza risk assessment tool (IRAT), determined that the virus has a slightly increased chance of causing a pandemic, with a score of 5.79, up from the previous score of 5.12. This places the risk within the “moderate” range according to the CDC tool.
The CDC explained that there is some uncertainty surrounding the assessment scores due to various factors such as the severity of the disease caused by the viruses and the level of immune protection in humans. Vivien Dugan, director of the CDC’s influenza division, emphasized that the IRAT is primarily used for government planning purposes and does not indicate a high risk to the general public.
The analysis was based on the first human case of H5N1 in the U.S. this year, reported in Texas. The assessment showed a fractional decrease in the public health impact of a potential pandemic caused by this virus. However, the recent cases of mild infections in workers culling chickens in Colorado raised concerns.
The United Kingdom’s Health Security Agency also raised its assessment of the pandemic risk of the H5N1 virus in cows due to sustained transmission in cattle in the U.S. Despite ongoing transmission in dairy herds, the virus has not shown increased capacity to spread among humans.
Michael Osterholm, director of the University of Minnesota’s Center for Infectious Diseases Research and Policy, described the situation as perplexing to researchers. The virus has caused severe illness in animals but has resulted in mainly mild human cases. Osterholm highlighted the importance of monitoring the virus for any changes that could enhance its ability to spread to humans.
Overall, while the risk assessment provides valuable information for government planning, the actual risk to the public remains low. The CDC continues to monitor the situation closely and collaborate with international partners to address any potential threats posed by the H5N1 virus.
