By Josh Nathan-Kazis

Any patient hospitalized with influenza should be quickly checked for H5N1 bird flu, the Centers for Disease Control and Prevention said Thursday, as the federal government continues to ramp up its preparations for a potential pandemic.

The new policy comes a week after a 5-year-old child in San Francisco tested positive for bird flu, despite no known exposure to infected animals. The child was not hospitalized and has recovered.

The H5N1 bird flu virus has been spreading widely in U.S. dairy cattle for nearly a year, and has been decimating poultry farms since 2022. The CDC has confirmed 67 human cases since last year in the U.S., one of them fatal. Experts have long feared that H5N1 has the potential to set off a human pandemic.

The CDC had previously said that flu patients who had been in contact with sick animals should be tested immediately for H5N1. The new guidance extends that recommendation to all hospitalized influenza patients.

CDC officials say they extended the guidance now because they are seeing more H5N1 patients whose illness they cannot track back to an infected bird or cow.

"What we've seen in recent weeks, as I mentioned, is an increasing number of cases among individuals where there have not been any identified exposure [to sick animals]," CDC Principal Deputy Director Dr. Nirav Shah told reporters on a Thursday press call. "That's a newer finding in the history of H5 -- not something that we've seen."

H5N1 is a subtype of influenza A, the broad category of viruses that cause most flu cases in the U.S. Under the current system, hospitals send batches of samples from patients who test positive for influenza A to public-health laboratories every few days to determine whether any of the patients have H5N1. That process is slow, Shah said, and often doesn't return results until the patient has already left the hospital.

Now, the CDC is telling hospitals that they should test all samples from hospitalized patients who test positive for influenza A within 24 hours to see if they are infected with H5N1.

Shah said that the CDC isn't changing its guidance because it is growing more worried about the H5N1 outbreak. The CDC continues to believe that the current risk from H5N1 to the general public is low.

Still, Shah said that the system needs to be able to identify patients with H5N1 more quickly. Knowing sooner if patients have H5N1 can ease the process of investigating whether their contacts are infected, and can help guide the broader public-health response.

The new announcement comes amid a flurry of last-minute efforts by the Biden administration to ramp up its preparations for a potential H5N1 pandemic, including the launch last month of a program to track bird flu in untreated milk, and new funding for pandemic-response programs.

Write to Josh Nathan-Kazis at josh.nathan-kazis@barrons.com

This content was created by Barron's, which is operated by Dow Jones & Co. Barron's is published independently from Dow Jones Newswires and The Wall Street Journal.

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January 16, 2025 13:23 ET (18:23 GMT)

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