There are many strains of the flu, hence why a new shot is needed every year. Some people will say, "what is the point? I just have to get a new one next year?" This mindset is why many people don't go out to get the flu shot. They may also believe it's a waste of time, because they'll end up sick anyway.
Another reason someone may not go and get the vaccine is due to their disagreeing belief of vaccines. Some people actually believe that with