Yes. The two years I didn't get it I caught the flu. And the years that the flu shot didn't cover the strain that ended up hitting our area, I caught the flu. So, for me, not getting the shot is a guarantee I'll catch the flu. And getting the flu sucks! I usually get a sore arm and feel run-down the evening I get my shot, and sometimes I get a mild fever, but that's it for side effects, and it's much better than catching the flu.