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

A shot for a flu vaccination. A late February meeting of scientists from around the world is figuring out the recipe for the best vaccine for the upcoming fall flu season.

After the U.S. withdrew from the World Health Organization, it wasn't clear they would participate in this WHO-led meeting to determine the recipe for the next flu vaccine.

(Image credit: Jens Kalaene/picture alliance)