US stops sharing flu data with WHO amidst one of its worst flu seasons

While the US declared its intention to leave the World Health Organization (WHO) on 20 January, the process of severing ties with the international public health body formally takes one year. Yet US health agencies have already retreated from nearly all coordinated global health efforts around influenza surveillance. The move could jeopardise the efficacy of the next batch of flu vaccines both for the US and the rest of the world.

This comes as the US is in the midst of its most severe flu season in 15 years. At least 29 million people in the country have caught the illness since October and roughly 16,000 have died from it – and the season is only half over.

Numerous factors are probably behind the surge, including lower vaccination rates, says Erin Sorrell at Johns Hopkins University in Maryland. 

All of this underscores the importance of an upcoming WHO meeting. Scheduled for 28 February, the meeting will bring together influenza experts from around the world to select which strains the next flu shot will target. The decision is based on influenza samples collected from 151 national laboratories across 127 countries. These samples are then further analysed at WHO collaborating centres to characterise how the virus spreads, evolves and interacts with vaccines and other treatments.

These seven collaborating centres, two of which are based in the US, play a major role in global influenza surveillance and response preparedness, says Maria Van Kerkhove at WHO. The trouble is, the US centres stopped communicating with WHO. 

WHO is currently working with other collaborating centres to fill the information gap left by the US, says Van Kerkhove. The halt in US communication shouldn’t impact the WHO’s ability to develop an effective flu vaccine for next season, she says. But it will certainly make it more challenging to do so in the future.

It will also have ramifications for US public health. “We don’t get to provide our input on strains that we are most concerned about in the US and discuss mutations that we are observing here. Our technical experts, who are some of the best in the world, are not able to contribute to that conversation,” says Sorrell. “So, we are not only putting the world at a disadvantage, but absolutely the average American who would be looking to be vaccinated next year against seasonal flu.”

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Source: The New Scientist, 21 February 2025