When you have kids, you get the flu shot, like 240 said. It's not just to protect you at that point. It's to protect them as well. I never used to get it either, until a doctor I trust made it clear to me that is was unsafe for the kids for me not to get it. My wife works in a hospital as well, so she has to get it as well.
Ironically, I got the shot this year, and I got the flu anyway. I'm about 2 weeks into it (nearing the end of it now) and it sucked bad. BUT I did not transmit it to my wife or kids. That, to me, is why I do it and have the kids get it.
I am not comfortable with it at all, but this year, I saw why it is important. Like someone said above, injecting hormones > danger then flu shots. Even pharma grade. But you'll see when you have kids. Your opinions change a lot.