PUBLIC HEALTHH5N1 Continues to Spread in the U.S. Amid Growing Concern About Threat to Public

Highly pathogenic avian influenza (HPAI) A(H5) viruses continue to spread across the United States, with nearly 86 million birds affected in 1,118 reported outbreaks across 48 states as of April 10. The CDC issued a health advisory last week informing clinicians, state health departments, and the public of a confirmed case of H5N1 in a human patient in Texas. As just two humans-both of who worked closely with livestock-have been infected with H5N1 in the United States ever (one in Colorado in 2022 and the recent case in Texas), public health authorities continue to emphasize that the risk to the general public remains low, despite worrying trends in the spread of this virus amongst birds and mammals in the US and Canada.

Pandora Reportwrites that not everyone is convinced.

Luciana Borio and Phil Krause discuss this in their article for STAT News that was published today, writing “The recent detection of H5N1 bird flu in U.S. cattle, coupled with reports of a dairy worker contracting the virus, demands a departure from the usual reassurances offered by federal health officials. While they emphasize there’s no cause for alarm and assert diligent monitoring, it’s imperative we break from this familiar script.”

STAT’s Helen Branswell covered the same topic in a piece last week, writing in part “To put these developments in perspective, STAT turned to Dutch virologist Ron Fouchier, a leading expert on H5N1, for his assessment of these latest twists in the H5 saga. Fouchier, who studies avian influenza at the Erasmus Medical Center in Rotterdam, was at the center of a controversy about H5N1 in 2012, when a U.S. scientific advisory group moved to restrict publication of research he and a team at the University of Wisconsin-Madison had done — separately — to see what mutations would be needed for the virus to be able to spread efficiently among people, so-called gain of function research.”

“Fouchier takes little solace from the fact that current versions of H5N1 seem to infect people less frequently, and to cause mostly mild illness when they do. The global range of H5 viruses — the sheer volume of the virus in nature — and the numbers of mammals H5 has shown itself capable of sickening is unprecedented, he said, making anticipating its future path harder than ever to gauge.”

Regardless of the official risk to the public, the last few weeks have brought several worrying developments as cows were once thought to be unlikely victims of H5N1, and frequent human contact with livestock gives the virus more opportunity to spread to people. Because of this, as Nature news explains, “Scientists are scrambling to assess how well candidate vaccines and antiviral drugs will work against the circulating strain and to update diagnostic kits for identifying infections in people quickly. They are also trying to understand whether the cows were infected by birds or another source, and are on alert for any changes in the situation that could raise the risk for people.”