I've been hearing that if I get a flu shot, I'll either become immune to the virus or I'll end up in bed for a week. Is it worth the hassle? -Joseph A., Chicago IL
“You should get a flu vaccine—no excuses!” says Susan J. Rehm, M.D., medical director of the National Foundation for Infectious Diseases. Since flu viruses change constantly, there’s some chance you can get the flu even if vaccinated, but the vaccine can’t cause the flu. (You might experience mild, short-lasting side effects such as a low-grade fever or aches.) Rehm advises getting vaccinated early, since it typically takes about two weeks for antibodies to develop after vaccination. Keep in mind: A vaccine won’t help you if you’ve already got the flu.