How long does it take for the flu vaccine to work?
There is no exact answer for how long it takes for a flu vaccine to start working. The exact
time it takes for a vaccine to reach its full effect varies for every individual. However, it
generally takes about two weeks for your body to generate a sufficient amount of antibodies to
protect you from the flu. During the first two weeks after receiving your vaccine you are still
susceptible to the flu and it is still possible to catch the flu despite the flu vaccine.