HHS urges clinical laboratories and public health labs to prepare for an increase in avian influenza A test orders during this year’s flu season
On January 16, the federal Centers for Disease Control and Prevention (CDC) issued a Health Alert Network (HAN) Health Advisory urging physicians and clinical laboratories to adhere to a shortened timeline for performing analysis and subtyping on all influenza A (H1N1) specimens during the current flu season. This is due to a marked increase in avian influenza A (H5N1, aka, bird flu) infections among humans.
The CDC suggests that hospitals treating patients for flu symptoms perform clinical laboratory tests for avian influenza A within 24 hours. This additional testing will pinpoint the specific type of flu infecting an individual patient and help prevent further spread of the bird flu virus.
“It’s the subtyping that takes us from knowing that a virus is in the general bucket of ‘influenza A’ to knowing more specifically whether it’s a garden-variety seasonal version of influenza A or, more rarely, a novel version of influenza A like H5N1,” CDC Principal Deputy Director Nirav Shah, MD, JD, told CNN.
According to the CDC, a panzootic of pathogenic avian H5N1 flu virus is currently affecting wild birds, poultry, dairy cows, and other animals throughout the country. There have been 67 total cases of bird flu identified in humans in the US since 2022, with 66 of those cases occurring in 2024.
The risk of humans contracting bird flu are low but is elevated among those who work closely with wild birds, poultry, and dairy cattle. The incidences of the flu virus in animals continues to increase, so CDC says it is important to identify potential bird flu cases in humans in a timely manner.
This demonstrates recognition by the CDC and the clinical laboratory profession that advances in molecular diagnostics and genetic testing now make it feasible for many hospital labs to perform these tests in-house on relevant patients. Such molecular testing is less expensive and produces a faster answer today, compared to just a few years ago.
This call for more lab tests in hospitals is also recognition of the value near-patient testing has from a public health perspective. Historically, it was regional and local public health labs that were sent specimens for testing from patients identified as having an infection that were a public health concern.
The good news is that this expands the role of hospital laboratories for all the right reasons. The downside is that hospital labs will probably see many test claims for these assays not be paid promptly by payers—or paid after unnecessary delays.
“The system right now tells us what has already happened. What we need is to shift to a system that tells us what’s happening in the moment. That is what we are doing today,” Nirav Shah, MD, JD (above), CDC principal deputy told CNN. Hospital and clinical laboratories will likely see an increase in orders for molecular and genetic testing for influenza A. (Photo copyright: Centers for Disease Control and Prevention.)
CDC Recommendations to Clinical Laboratories
The CDC alert also acknowledges that most individuals infected with avian flu were exposed to the virus via the handling of infected dairy cows or poultry in unprotected workplaces. There are no known cases of human-to-human transmission of the disease.
Most cases of avian flu in humans have been clinically mild and the patients quickly recover. However, on January 6, the CDC announced that an elderly patient with underlying health conditions in Louisiana who was previously hospitalized with severe avian influenza A illness had passed away. This case was the first confirmed death in the US attributed to the illness.
The CDC’s Health Advisory makes the following recommendations to clinical laboratories:
- Subtype respiratory specimens that are positive for influenza A, but negative for seasonal influenza A virus subtypes, and forward those specimens to a public health laboratory within 24 hours.
- Refrain from batching specimens for consolidated or bulk shipment to public health laboratories if that process could result in shipping delays.
- Notify public health officials if a hospital or clinical lab does not have access to influenza A virus subtyping and arrange for a public health or commercial lab with this testing capability to perform the analysis.
- Clearly link specimens to clinical information from the patient to ensure the prioritization of severely ill and ICU patients.
- Immediately contact local 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 time-critical actions.
The CDC’s Health Advisory also states public health laboratories should complete influenza A subtyping assays within 24 hours of receipt and report those results to the CDC, as required.
“One of the motivators of accelerating testing [is] so that we are, again, able to faster see difference between signal and noise, given that the volume of hospitalizations is going up as expected in a rather routine flu season,” Demetre Daskalakis, MD, MPH, director of the CDC’s National Center for Immunization and Respiratory Diseases (NCIRD), told CNN.
Preparing for more Bird Flu in Humans
According to the CDC, approximately 100,000 Americans have been hospitalized with type-A flu this season. The agency expects another 100,000 hospitalizations due to the virus before the end of this year. CDC is tracking flu infections on a weekly basis. Data can be reviewed on its website.
Other government organizations also are developing methods intended to curb the spread of the influenza virus. The federal Department of Agriculture recently launched a national program to test for bird flu in untreated milk. And the US Department of Health and Human Services (HHS) allocated $211 million in new funding to address emerging infectious diseases.
On January 17, the HHS announced it would give $590 million to Moderna to “accelerate the development of mRNA-based pandemic influenza vaccines and enhance mRNA platform capabilities so that the US is better prepared to respond to other emerging infectious diseases.”
“The funding will allow us to bring the benefits of mRNA vaccine technology to bear against a wider array of emerging threats,” said HHS Assistant Secretary for Preparedness and Response Dawn O’Connell, JD, in the announcement. “mRNA technology can be faster to develop and easier to update than other vaccines making it a helpful tool to have against viruses that move fast and mutate quickly.
Hospital laboratories and public health labs should prepare for a spike in test orders for avian influenza A as this year’s flu season progresses. As bird flu increases in animals, it increases the possibility that the disease might infect humans.
—JP Schlingman
Related Information:
Accelerated Subtyping of Influenza A in Hospitalized Patients
CDC Urges Faster Testing to Find Human Bird Flu Cases
Weekly US Influenza Surveillance Report: Key Updates for Week 2, Ending January 11, 2025
CDC Urges Hospitals to Fast-track Bird Flu Testing
First H5 Bird Flu Death Reported in United States
Top CDC Officials Warns US Needs ‘More Tests’ in Face of Bird Flu Fears