The best way to protect against flu and its potentially serious complications is with a flu vaccine. The Centers for Disease Control and Prevention recommends that almost everyone six months and older get a seasonal flu vaccine each year, ideally by the end of October. However, as long as flu viruses are circulating, vaccination should continue throughout flu season, even into January or later.
Flu vaccination is especially important for people 65 years and older because they are at higher risk of developing serious flu complications. Flu vaccines are updated each season to keep up with changing viruses. Also, immunity wanes over a year so annual vaccination is needed to ensure the best possible protection against flu. Because immunity may decrease more quickly in older people, it is especially important that this group is not vaccinated too early (in July or August). September and October are generally good times to be vaccinated for people 65 years and older.
A flu vaccine protects against the flu viruses that research indicates will be most common during the upcoming season. Flu vaccines for 2021-2022 have been updated from last season’s vaccine to better match circulating viruses. Immunity from vaccination fully sets in after about two weeks.
Because of age-related changes in their immune systems, people 65 years and older may not respond as well to vaccination as younger people.