Why People Still Get the Flu Despite Vaccination

The flu shot helps protect you from the flu, but you can still get sick.

The flu virus changes every year, so the shot might not be a perfect match.

Your body needs time to build protection, about two weeks after the shot.

The shot's protection can also wear off.

Sometimes, what seems like the flu might be a different virus.

Even if you get the flu after vaccination, the shot usually makes the illness less serious, preventing serious problems.