US reports fourth human case of bird flu
The U.S. reported its fourth case of bird flu on Wednesday at a Colorado dairy farm. Authorities are working to expand the availability of potential vaccines and commercial tests and provide financial assistance to affected farmers.
The dairy farmer had close contact with cows that tested positive for H5N1, a highly pathogenic bird flu, and the worker reported only ‘eye symptoms’, according to at the Centers for Disease Control and Prevention (CDC).
The person took antiviral medication and has recovered, the CDC said. The agency is sequencing a sample of the virus to see if it has developed any worrisome mutations.
More than 780 people have been checked for symptoms this year and at least 53 have been tested for H5N1, the CDC said reportsThe vast majority of these tests were conducted in Michigan.
Colorado has the highest number of affected herds, according to to the United States Department of Agriculture (USDA). A cat in Colorado has also tested positive after no known contact with poultry or dairy farms.
Before this year’s outbreak in dairy cattle, the only previous human case identified in the U.S. was in Colorado in 2022, after an inmate was exposed to the virus while culling a flock of infected poultry.
The new case follows an announcement the day before by U.S. officials about plans to boost supplies of H5N1 vaccines and expand testing availability.
The U.S. is working with vaccine maker Moderna to help develop and produce mRNA bird flu vaccines “if needed,” said Dawn O’Connell, assistant secretary for preparedness and response (ASPR). Human safety and efficacy trials would likely begin next year, she said.
While the $176 million contract While it focuses on H5N1 vaccines, it could also be used to develop or purchase vaccines against other flu strains or emerging infectious diseases, McConnell said.
The U.S. has also ordered 4.8 million doses of another type of H5N1 vaccine, which is expected to roll off the production line in mid-July, “faster than we initially anticipated,” McConnell said.
These vaccines still need to be approved by the Food and Drug Administration (FDA) before they can be administered to humans.
Officials say the risk of bird flu to humans remains low and the H5N1 vaccine is not currently recommended for anyone.
Officials also raised the possibility of using antiviral drugs against flu to prevent transmission of the H5N1 virus among people, if the virus mutates and becomes more effective at human-to-human transmission.
“The vaccines are generally better at preventing severe disease than they are at preventing transmission,” said Nirav Shah, deputy director of the CDC, adding that wider distribution of antivirals could help with the latter.
Expanding the availability of testing would allow people at risk of H5N1 to go to a commercial lab to get tested, which could improve access to testing and make it faster.
The U.S. currently has about 750,000 tests for H5N1, with another 1.2 million expected in the next two to three months, all of which are being run in public health labs. The CDC is working to share its test designs with commercial companies, and on June 10 the agency opened a call for companies to propose new H5N1 test designs.
On Monday, the USDA opened a financial assistance program for dairy producers with herds infected with H5N1. While infected cows usually survive, their milk production often drops, and discarding H5N1-infected milk means lost revenue.
The new program would allow any dairy farmer with H5N1-positive cows to apply for federal aid, similar to programs that exist for poultry farmers who lose their herds. Experts hope it will encourage producers to test their herds and help curb the spread of bird flu.
Six states have also signed up for the USDA’s voluntary pilot program for dairy herd status, and 24 herds are participating in the agency’s financial assistance programs to improve on-farm biosecurity and testing.
There’s also research underway to develop avian flu vaccines for cows, but that process takes time, said Eric Deeble, the USDA’s acting senior advisor for the H5N1 response. “It’s going to be a while before a vaccine is available … and in the meantime, we’re going to continue to emphasize biosecurity” — such as limiting the number of people on farms or cleaning and disinfecting equipment and clothing. So far, studies indicate that people are moving the virus between farms via shared workers, cows, vehicles and equipment.