The mutated strain, known as subclade K, is causing a surge in cases in the United Kingdom, Canada, and Japan. Here's what to know.

H5N1 bird flu has been circulating in U.S. wildlife since late 2021 but has caused only one human fatality. Now a different ...

Pfizer's mRNA flu vaccine worked better than a standard flu shot in a large Phase 3 trial, researchers reported in the ...

California could see an early and especially sharp start to the annual flu season, as a combination of low vaccination rates and late mutations to the virus may leave the state particularly exposed to ...

Recombinant quadrivalent influenza vaccine (RIV4) and standard egg-based quadrivalent inactivated IV (IIV4) show comparable effectiveness in reducing influenza-related hospitalization among older ...

Those who got flu shots were were less likely to end up in the emergency room. People who got a flu shot earlier this year may be less likely to suffer a severe COVID-19 infection down the road, ...