I know, some do, some don't. Arguments on either side. One of the most ardent refusals I've heard was from a senior scientist and erstwhile acting director of the National Institutes of Health who had worked on flu vaccines, so take that for what it's worth. Knowing both arguments, I've had flu shots regularly over the years hoping it either is efficacious and/or that it was good placebo, which is sometimes as good as efficacious. So far, so good, with the flu. My object in posting this is, if you "do" flu shots, late September or early October seems to be the most effective timing in terms of getting best immunity according to the CDC site, though they'd rather you get it earlier or later than not at all, all the way into the flu season in late winter. I won't try to give much advice on this, since I'm not a pro on the subject, but we're getting to prime time if you're getting a flu shot. Kids and older people benefit the most, since they have the worst time if they catch the flu.