or how about just pointing out the silliness of the anti-vaxer conspiracy theories in general?
I happen to like vaccines very much, I was a pincushion for them when I was in the Navy, and occasionally go for the inexpensive flu shots when available.
So yeah SOME real dangers from vaccines, but you just have to have the smarts to watch for them. Flu shots CAN give you the flu, or a rash, or other allergic reaction. But they usually don't. So you either get a doctor to monitor it, or show some common sense and read the warnings on the label...
(/me not a doctor, so YMMV)