CP, like most childhood diseases, can be extremley nasty if you get a bad dose of it, are immuno-suppressed, or have underlying health problems... I think a lot of the reason behind the vaccine would be to protect the members of our community who are more vunerable and susceptible to it, again by herd immunity (just hypothesising- don't quote me).

I had my first dose of Gardasil, and I was kicking myself for it. I didn't put nearly as much thought or research in as I did with kid's vaccines. I can speak first hand of the side effects- I fainted about 15 minutes after i had my first dose, in the middle of a shopping centre.