I’ve never had a flu shot. One year when we lived in Michigan, our next door neighbor got the flu shot, and we ran into him when he arrived home from getting the shot. He had the flu within 24 hours, and hubby and our children all had it within days. That ruined me on those shots.
We had swine flu hit our house before it was a big news item. One of our boys caught it from his baseball coach who had gone to Mexico for a weeklong vacation. The flu shot would not have helped.
H1N1 strain was included in the vaccine by that winter (and still is). I didn't elect the flu shot for my kids that season because they had also already contracted the swine flu (diagnosed in the ER) so had natural immunity. But the immunity is temporary so they and I have had the shots since (mine last week, and it hurt pretty bad for an hour and then quit. Usually I feel nothing).