U.S. hasn't sent essential seasonal flu data to WHO ahead of key vaccine meeting

Seasonal flu vaccines need to be updated each year because the virus changes so frequently. But the U.S. hasn't contributed its information on what's spreading there since January, a World Health Organization (WHO) official said.

For seasonal influenza, which forced schools to shut down in some American states earlier this month, the data isn't being shared, Dr. Wenqing Zhang, head of the WHO's global influenza program, told journalists in a webinar on Wednesday.

The U.S. Centers for Disease Control and Prevention (CDC) and U.S. Food and Drug Administration (FDA) normally participate in global discussions hosted by WHO on influenza vaccinations twice a year.

Detailed seasonal flu information is important to monitor outbreaks globally and to inform which influenza strains should be included in vaccines for the Northern Hemisphere's following winter.

"Since 20th January, CDC has not yet reported into the WHO platform of Flunet and FluID," Zhang said, referring to two databases for influenza surveillance. As of last week, the U.S. was publicly releasing some flu information nationally.

When U.S. President Donald Trump was inaugurated on Jan. 20, he called for his country to leave WHO, starting in January 2026.

A WHO meeting is scheduled for next week in London to discuss the composition of influenza vaccines. So far, WHO says the U.S. has not indicated whether it will attend.

At the meeting, participants look at the data to come to a consensus on if the strains in the previous seasonal vaccine are still thought to work or if they need to be updated.

Kanta Subbarao says the U.S. also contributes expertise on vaccine effectiveness and key material used by vaccine manufacturers.

Subbarao, a pediatric infectious diseases specialist and influenza scientist now working at Laval University in Quebec City, served as director of WHO's Collaborating Centre for Influenza in Melbourne, Australia. It is one of five such centres for human influenza along with the U.S. CDC in Atlanta, England, China and Japan.

"I think this is a very bad time for the flu vaccine," Subbarao said.

"The CDC and FDA are very actively involved normally in this process, so it's a little hard for me to fathom what it will look like without them."

Subbarao said the U.S. collaborating centre often receives influenza viruses from Canada and other parts of the Americas as well as Africa and parts of Asia.

Dr. Keiji Fukuda, a physician and epidemiologist who has attended influenza vaccine meetings and worked for both WHO and CDC, said it's crucial for U.S. experts to go.