No, a flu vaccine cannot cause the flu.
The viruses in a flu shot are killed (inactivated) and can’t cause the flu illness. While a flu vaccine can't give you the flu illness, there are potential side effects from getting a flu vaccine. These side effects are usually mild and short-lived, especially when compared to symptoms of flu.
Why should I get a flu shot?
Flu vaccines keep you from getting seriously sick with the flu.
Vaccines can prevent you from getting flu illness. If you do get the flu, vaccines can prevent you from becoming severely ill, especially if you have a chronic health condition like diabetes, heart disease or chronic lung disease. If you spend time around vulnerable populations like kids or seniors, you can protect them from serious illness by getting the vaccine.
Find more information at cdc.gov/flu