You know, I really can't add a thing to this article. I only wish that the morons of the world (ahem, Jenny McCarthy) would read it with an open mind and actually learn something. But then again, pigs'd fly first. Instead, credulous people choose to believe in crackpot theories and revile people who work hard to reduce sickness in the world. Oh, and make death threats against them. Why oh why, do people actually listen to Jenny instead of Amy?
Truly -- while people believe that they are exercising their rights to make their own medical decisions and appropriate medical decisions for their children, inadequate immunization brings a great deal of risk to the population as a whole, as well as to each individual person. Herd immunity is a function of a large enough percent of the population being vaccinated -- if that number too low, herd immunity disappears. You need quite a high percentage of population vaccinated to provide herd immunity for the community. For example, measles and pertussis are rather contagious and may require up to 94% of the population to be vaccinated for that vaccine to confer herd immunity.
Herd immunity confers protection to those who either can't receive a vaccine due to health reasons (immunocompromised, cancer, chemotherapy, infants) or people whose vaccines have failed (they don't "take" in everyone). Therefore, when these "concerned parents" choose not to vaccinate their children, they are actually endangering the health of other parents' kids, even if those kids are vaccinated. So while part of me says "fuck you, evil parents who don't vaccinate their kids, your kids'll pay for it", in reality, it is those who are sick and vulnerable that bear the brunt of these people's folly.