Rhetorical Inoculation

I got into a debate with a student about vaccines the other day in class (because I mentioned I was getting my swine flu and tetanus shot) and I became a bit passionate about the topic, which is always embarrassing-- I try to remain as neutral as possible about most things-- but I ended up asking the class to raise their hands if they were for polio and the death of millions of children, and then I asked the class who was against polio and the death of millions of children-- but I got my just desserts, as my arm really hurts where I got my tetanus shot (but at least I have no chance of getting lock-jaw).