The H5N1 avian influenza virus is mutating to evade immune defenses in mammals following prior infection or vaccination.

New research suggests that past exposure to seasonal flu viruses may help protect people from severe illness caused by the ...

Early flu exposure helps immunity against H5N1 infection, with older adults having stronger antibody responses.

Scientists say a concerning genetic mutation has appeared in H5N1 bird flu infected cats living in a New Jersey suburb of New ...