About
- Level: Laboratory Advisory
- Audience: Clinical Laboratory Professionals
LOCS message
On January 16, 2025, the U.S. Centers for Disease Control and Prevention (CDC) issued a Health Alert Network (HAN) Health Advisory following sporadic human infections with avian influenza A(H5N1) viruses amid high levels of seasonal influenza activity. CDC recommends a shortened timeline for subtyping all influenza A specimens among hospitalized patients and increasing efforts at clinical laboratories to identify non-seasonal influenza. To prevent delays in identifying human infections with avian influenza A(H5N1) viruses, clinicians and laboratorians are reminded to test for influenza A-positive specimens from hospitalized patients, particularly those in an intensive care unit (ICU).
CDC still considers the risk from avian influenza A(H5) viruses to the public to be low but is closely monitoring this dynamic situation.
Recommendations for Clinical Laboratories:
- Subtype and send respiratory specimens that are positive for influenza A but negative for seasonal influenza A virus subtypes [i.e., negative for A(H1) and A(H3)] to a public health laboratory as soon as possible and within 24 hours of obtaining the results. Do not batch specimens for consolidated or bulk shipment to the public health laboratory if that would result in shipping delays for any such specimen.
- If influenza A virus subtyping is not available at the hospital or the clinical laboratory of the treating facility, public health officials should be notified, and arrangements made for influenza A virus-positive respiratory specimens to be subtyped at a public health laboratory or a commercial laboratory with this testing capability. Specimens should be clearly linked to clinical information from the patient to ensure specimens from severely ill and ICU patients are prioritized.
- Immediately contact the state, tribal, local, or territorial public health authority if a positive result for influenza A(H5) virus is obtained using a laboratory developed test (LDT) or another A(H5) subtyping test to initiate important time-critical actions.
Recommendations for Public Health Laboratories:
- Complete influenza A virus subtyping assays within 24 hours of receipt and report results to CDC, as required.
Please review the HAN for more information including recommendations for testing hospitalized patients, clinicians, clinical laboratories, public health laboratories, and the public.
We encourage you to share this message widely with your network(s).
Resources
- Bird Flu | CDC
- Accelerated Subtyping of Influenza A in Hospitalized Patients | HAN
- H5 Bird Flu: Current Situation | CDC
- 2024-2025 Influenza Season: Surveillance For Novel Influenza A and Seasonal Influenza Viruses | CDC
- Interim Guidance for Infection Control Within Healthcare Settings When Caring for Confirmed Cases, Probable Cases, and Cases Under Investigation for Infection with Novel Influenza A Viruses Associated with Severe Disease | CDC
- Case Definitions for Investigations of Human Infection with Avian Influenza A Viruses in the United States | CDC
- Interim Guidance for Employers to Reduce Exposure to Avian Influenza A Viruses for People Working with Animals | CDC
Contact us
Please use the information below if you have any questions.
- If you are a clinical or public health laboratory professional, contact LOCS.
- For media inquiries, contact the CDC Newsroom.
- For all other questions, contact CDC-INFO.
Thank you,
The Laboratory Outreach Communication System
Laboratory Outreach Communication System (LOCS) | Division of Laboratory Systems (DLS)
Office of Laboratory Systems and Response (OLSR)
Centers for Disease Control and Prevention (CDC)
LOCS@cdc.gov
www.cdc.gov/locs/php/about