FDA chief says bird flu risk to humans is low, but agency is preparing

May 8, 2024

The Food and Drug Administration (FDA) is preparing in case the current strain of avian flu circulating in the U.S. jumps to humans on a large scale, the agency’s commissioner told senators Wednesday. 

FDA Commissioner Robert Califf told the Senate Appropriations Committee that while the threat to humans is low and milk products are safe, the FDA and other agencies are working to scale up medical countermeasures. 

“So we got to have testing. Gotta have antivirals, and we need to have a vaccine ready to go. So we’ve been busy, getting prepared for if the virus does mutate in a way that jumps into humans on a larger level,” Califf said. 

Califf said there’s a possibility that the H5N1 influenza virus could jump to humans and infect the lungs.

“That would make it perhaps transmissible through the airways, which would be really bad,” he said. 

Califf stressed the public health risk is low, but the agency doesn’t want to be caught flat-footed. The mortality rate for cattle is less than 1 percent, and the virus has so far caused mostly mild illness. 

But it could be spreading asymptomatically, and Califf said dairy farmers and workers need to be protected with personal protective equipment (PPE). The use of PPE is routine in the poultry industry, but it’s new for the cattle industry, and Califf said he recognizes implementation will take time. 

“If we institute the countermeasures now and reduce the spread of the virus now, then we’re much less likely to see a mutation that jumps to humans for which we’re ill-prepared,” Califf said.

The current bird flu strain has infected 36 dairy cattle herds across nine states; Colorado, Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, South Dakota and Texas, according to the Centers for Disease Control and Prevention. 

There’s been just one documented case of human infection to date, which was found in a farmworker in Texas. His only symptom was conjunctivitis, from which he recovered. 

Califf said the FDA is confident vaccine production can be scaled up if needed, and the existing mRNA platforms can be deployed to match new strains.   

“We’re in an enviable position compared to any time in the history of the world,” Califf said. “Viruses are relatively simple, so coming up with a matching vaccine is entirely possible in a short period of time.”  

But, he added, “we’ve got to have the funding to keep the source warm.”