When I was in the ARMY I resisted the flu vaccine. I took all the required ones for the deployments but since I had never had the flu and didn't want to introduce it into my body I managed do dodge the docs and avoid the flu vaccine. I was threatened with discipline but when push came to shove they did nothing.
I have still never had the flu. I have only thrown up three times in my life (two of those due to alcohol). I am certain I was exposed to the Corona virus in Feb/Mar due to people around me who were displaying every symptom, but never had more than a sore throat for a day. My immune system is up to the task.
I am not anti vaccine but fight to avoid the ones that are not particularly effective due to various strains of the disease being in play. The flu vaccine is always the best guess as to which strain to treat for in a given year. My children have had the important ones but we claim a religious exemption for flu with our school system. My kids have never had the flue either.