With regards to the question of "many Googlers being antivaxers", I wonder how common it is for a family to not think of themselves as anti-vax, but through bad luck in or poor research in selecting a pediatrician they end up getting fewer vaccines for their kids. Personally, I think I might know one such family where that seemed to be the case, someone who didn't seem to realize something kooky their pediatrician had said. I would imagine that would come up by the time they go to school though.