1957–1958 influenza pandemic
Flu is a serious disease, caused by influenza viruses, that can lead to hospitalization and even death. Your best defense is vaccination, which provides important protection from flu and its potential complications.
Influenza (flu) viruses typically spread in fall and winter, with activity peaking between December and February. Every flu season is different, and the substantial health impacts can vary widely from season to season, with some flu seasons being worse than others.
Flu viruses can change from year to year, so the vaccine is updated every year to protect against new flu virus strains that are expected to circulate in the United States. The FDA plays a key role in making sure flu vaccines are safe, effective, and of high quality.