Why do I get vaccinated each year?
I got the flu vaccine last year - why do I need it again?
The flu virus changes and adapts very rapidly, partly because so many people contract it year to year.
As a result of this adaptation, new vaccines are developed each year that better prevent the spread of the virus. At the same time, our immunity declines over time, so we need a 'booster' of sorts.
However, there are several thousand variations of the virus, and while the vaccine may not cover ALL of them, it is intended to protect against the most common variants based on reported cases.