The only time that I ever got the flu was about a month after my first flu shot.
i get flu shot every year due to lung problems, an most folks will be sick aroudn me, and i might get sick, but get it pretty mild compared to them that didn’t get the shot- I was on meds that caused lung issues like bronchitis, and got a flu one year that i didn’t get the shot, and ended up in ER fighting to breathe- so since then i do get flu shots-
but my nephew got the flu shot just once and got mega sick- he was one sick person for a week or so- so he won’t get them anymore-