The federal agency is asking hospitalists and labs to accelerate this process in order to know if they are dealing with avian influenza.
Image credit: CDC
Today, the Centers for Disease Control and Prevention (CDC) has issued a health advisory requesting clinicians and laboratories to expedite the subtyping of influenza A-positive specimens from hospitalized patients, especially those in the intensive care unit (ICU). The federal agency said they are looking for this be performed within 24 hours and they stated on their website that this type of approach will look to prevent delays in identifying human infections with avian influenza A(H5N1) viruses, in order to enable better patient care and timely infection control and case investigation. 1
CDC gets involved with investigations once a case has been determined to be avian influenza.
Subtyping is significant to determine in people who have a history of relevant exposure to wild or domestic animals infected or possibly infected with avian influenza.
The CDC has issued a health advisory urging rapid subtyping of influenza A-positive specimens, particularly in ICU patients.
Subtyping is crucial for identifying potential cases of avian influenza A(H5) in individuals with exposure to infected animals.
Despite 67 confirmed human cases of avian influenza A(H5N1) since 2022 (66 in 2024), the CDC assesses the risk to the general public as low.
CDC still considers the risk from avian influenza to be low to the general public but is closely monitoring this dynamic situation. At this time, while seasonal influenza levels are high nationally, nearly all people who are currently hospitalized with influenza A virus infections probably have seasonal influenza.
CDC has routinely recommended hospitals perform influenza testing for inpatients with suspected influenza, and now with the highly pathogenic avian influenza A(H5N1) viruses circulating in animals, and in some limited cases, humans, this becomes a more significant public health concern.
The agency points out that most influenza tests ordered in clinical settings do not distinguish avian influenza A(H5) viruses from seasonal influenza A viruses; a positive result simply confirms influenza A virus infection. Therefore, using tests that identify the seasonal influenza A virus subtype will help identify whether infection with a seasonal influenza A virus is present. If a test result is positive for influenza A virus but negative for seasonal influenza A virus subtypes [ie, A(H1) and A(H3)], the virus detected might be a novel influenza A virus, such as influenza A(H5), and specimens should be prioritized for shipment to a public health laboratory for additional testing.
There are a few commercial laboratories offering influenza A(H5) subtyping in the clinical setting. Additionally, the FDA offers a list of influenza A typing and subtyping tests. Services like diagnostic and subtype testing that are reasonable and necessary to diagnose illness are covered in most cases by both public and private health insurers.
As of today, there have been a total of 67 human cases diagnosed with 1 fatality. This goes back to 2022, and 66 of these cases were diagnosed in 2024.
