CDC’s Recommendation to Accelerate the Subtyping of Positive Influenza A Respiratory Specimens from Hospitalized Patients
By Bridget Parsons
What laboratories need to know in light of recent avian influenza cases
The Centers for Disease Control and Prevention (CDC) issued a key recommendation on January 16, 2025 for healthcare providers to expedite the subtyping of positive influenza A respiratory specimens from hospitalized patients.1 This guidance comes at a critical time, as a result of the recent cases of highly pathogenic avian influenza A (H5N1) raising significant public health concerns. While the CDC’s recommendation is more crucial than ever for managing influenza in patients, understanding your testing options, such as the LIAISON PLEX® Respiratory Flex Assay, can help you stay aligned with evolving testing guidelines in the fight against this pathogen.
Why subtyping influenza A is critical right now
Influenza A is the primary driver of seasonal influenza outbreaks, but it’s also the most likely to mutate into novel strains that could pose significant public health risks. The avian influenza A (H5N1) has been a cause of particular concern over recent months due to an uptick in human infections. This strain, while not yet a widespread threat to humans, has the potential to mutate rapidly, which is why the CDC’s recommendation for subtyping influenza A respiratory specimens has never been more critical.
- Distinguishing between seasonal influenza and avian influenza strains
By subtyping positive influenza A specimens, you can distinguish between seasonal strain (H1N1 or H3N2) or a more concerning strain like avian influenza A (H5N1). Avian influenza primarily spreads from birds to humans, often through direct contact or exposure to contaminated environments. Furthermore, if the patient has a known history of poultry exposure, early identification of H5N1 is critical to ensuring appropriate patient management, including stricter isolation measures and reporting to public health authorities. - Tracking emerging threats
While seasonal influenza strains follow a predictable pattern of evolution each year, avian influenza presents a higher level of uncertainty. Subtyping tests allow monitoring of whether H5N1 or similar strains are becoming more prevalent in your community and can provide early warning signs of shifts in the virus’s behavior, allowing health authorities to respond quickly. - Facilitating appropriate public health responses
Subtyping for H1 and H3 influenza A cases helps not only with individual patient management but also with the larger public health response. Early detection of avian influenza allows public health officials to take prompt action, such as issuing targeted advisories, deploying appropriate antivirals, and tracing contacts of infected individuals. By incorporating subtyping into your testing strategy, you’re helping to contribute critical data that allows for a more nuanced, informed public health response.
Preparing your laboratory
Not all influenza tests can provide subtyping results directly. In many cases, subtyping may require additional resources or a longer processing time, which could delay diagnosis and treatment. Ensure your laboratory is equipped to handle subtyping and prioritization of timely results for positive influenza A respiratory samples, especially in cases where avian influenza is suspected.
Diasorin’s newest system, the LIAISON PLEX®, is uniquely designed to help laboratories meet the changing demands of respiratory testing. The LIAISON PLEX® Respiratory Flex Assay provides a selection of 19 respiratory pathogens but allows you to create customized patient- and season-specific mini panels, unlike static syndromic panels. You can easily add or remove H1 and H3 from a mini panel as seasonal or outbreak demands occur.
Moreover, LIAISON PLEX® Flex Software allows users to instantly append additional targets after a run completion if desired. So, if a non-subtyping custom panel returns a positive influenza A result, users could easily choose to add H1 and H3, without additional consumables or testing time.
To learn more about the LIAISON PLEX® System and Assays that may be a fit for your laboratory, visit our website or contact us.
A vital step in protecting public health
The CDC’s recommendation to subtype positive influenza A respiratory samples is an important step in maintaining vigilance during influenza season, particularly in light of the potential threats posed by avian influenza A (H5N1). By identifying and differentiating between seasonal and more concerning strains like H5N1, you can help protect your patients, your community, and ultimately contribute to the global fight against influenza.
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