It boggles the mind that we still have to (re-)explain one of the better understood medical discovery every few decades.<p>Vaccines have been experimented with since the 18th century, and formalized by Pasteur in the 1870s. We've had nearly <i>140 years</i> of data on the subject, if there was something statistically significant we would know by now, no?<p>I believe antivax ideas are in some ways the result of vaccination being a victim of its own success: it just works, so there is no visible manifestation of its effect (no massive amount of sick people around), and because we are wired to look out for potential threats some people will zoom in on this odd practice of injecting people with dead viruses, and come up with all sorts of paranoid ideas. If you go to third world countries were mass vaccination is either recent or an ongoing process (and were people <i>do know</i> what happens when there is no vaccination) and try to take their kids' vaccines away from them because of some antivax delusion, they will kick your teeth in, no question.