Why it’s a bit surprising that the U.S. is attending a key global flu meeting : NPR

A flu vaccine. At the end of February, a meeting of scientists from around the world aims to determine the recipe for the best vaccine for the upcoming fall flu season.

Jens Kalaene/photo alliance/via Getty Images

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Jens Kalaene/photo alliance/via Getty Images

Over the past week, about 50 scientists from around the world have crowded into a conference room at a Hilton hotel in Istanbul, Turkey.

Their goal is to design a flu vaccine that will provide the best protection for the next flu season, starting in fall 2026. Every day, they review tons of data on how the virus is doing around the world, how last year’s vaccine performed, and which strains might be easiest for a vaccine to mass produce.

The meeting, convened by the World Health Organization twice a year, is a critical moment for WHO’s global influenza surveillance and response system.

It’s also “really tedious,” says Dr. Dan Jerniganwho led the National Center for Emerging and Zoonotic Infectious Diseases at the Centers for Disease Control and Prevention from 2023 to 2025. “In order for you to make the best choice about what to put in the vaccine, you have to look at a lot of things.”

In recent years, CDC scientists like Jernigan have played a major role in these meetings. But after the United States officially withdrew from the WHO in January, it was unclear whether it would attend a WHO-led meeting. Earlier this month, the administration confirmed that the CDC would send staff despite the United States’ exit from the organization, albeit virtually rather than in person.

“Representatives from the CDC will participate in the meeting to support international technical collaboration,” the Department of Health and Human Services said in a statement to NPR. “Their participation will focus solely on providing technical expertise, sharing surveillance data, and contributing to scientific discussions that inform vaccine strain recommendations. This participation does not change the United States’ position on WHO withdrawal.”

“I think this speaks to the irreplaceable nature of these multi-country networks,” says epidemiologist Jennifer Nuzzodirector of the Pandemic Center at Brown University. The Trump administration “can bluster and say, ‘We’re not going to do that,’ but at some point it comes up against the reality that there is no other way to protect the nation.”

However, the withdrawal of the United States from the WHO has called into question this global system and could ultimately diminish the influence of the United States in the development of the flu vaccine.

Global data collection

At any given time, the flu is spreading somewhere on Earth. Each year, approximately 1 billion people are infected. And throughout the year, the WHO surveillance system collects data on these sick patients in 130 countries.

These samples are then sent to seven larger laboratories, including the CDC in the United States. They are called WHO collaborating centers and try to make sense of all this viral data and select strains that might be suitable for vaccines.

This global system depends on the constant flow of samples from many countries to these seven largest laboratories. The WHO foots the bill for sending the samples, but when its biggest donor — the United States — pulled out last year, the flow of flu samples slowed largely because of the loss of U.S. dollars. Fewer samples means a dimmer view of the flu’s evolution, which could make it harder to determine which strains to put in next season’s vaccine.

“There has been a slight decline in the circulation of influenza vaccines globally due to a funding issue,” said Maria Van KerkhoveActing Director of the Department of Epidemic and Pandemic Threat Management at WHO, during a press conference on February 11. “But we were able to resume shipping around the world.”

Jernigan is nevertheless concerned about the long-term viability of the system, given the WHO’s financial constraints. The recent rise “doesn’t mean things are back to normal,” he said.

Another departure from normality is the absence of U.S. officials literally at the conference table.

“You want the whole process to be very objective and quantitative, but ultimately the interaction of different researchers is really important,” says Jernigan. CDC researchers have always had a lot of influence in choosing which strains to include in the vaccine. But with U.S. officials participating only virtually and the United States more generally avoiding international collaboration, representatives from other countries may be less inclined to follow the U.S. lead.

“You want your country’s issues to be represented in the flu virus selection” to ensure the best match, Jernigan says. With the United States only present virtually, he said, “they really have no incentive to select the vaccine virus that represents what might be circulating in the United States.”

NPR asked the Department of Health and Human Services, which houses the CDC, to address this concern, but the agency did not provide a response.

On Friday morning, the WHO will announce the committee’s recommended strains for next year’s flu vaccine. Manufacturers then begin the production process, which takes approximately nine months until the plates are ready for use.

“It is the ultimate multilateral product of a global system,” says Dr. Ali Khandean of public health at the University of Nebraska. “It is at least reassuring that the CDC is present at these meetings,” he says, but “whether we attend or not, we are seeing a loss of influence of the US government in the area of ​​global health.”