This letter to the New England Journal of Medicine reports an increase in the rate of non-medical exemptions from the childhood vaccinations generally required by state law. (Non-medical exemptions are permitted in 48 of the 50 United States.) States that allow "philosophical," as opposed to only "religious," exemptions to mandated childhood vaccinations, had higher rates of exemption, as did states with "easier" opt-out provisions. Easy opt-out states allow parents to opt out of the vaccination requirement by filling out a standardized form supplied by the school; harder opt-out provisions require an original and/or notarized letter from the parent, or a form obtainable only from the state health department.
For whatever reason--but certainly including unscientific vaccine/autism fear-mongering--there has been a dramatic decline in US parents' willingness to vaccinate their children. The result has been the return of deadly childhood diseases including pertussis, whooping cough and measles. Vaccination is among the most effective public health measures. Certainly, states should make it harder for parents to opt out of vaccination programs for non-medical reasons. But rates of opt-out are on the rise even in "difficult" opt-out states, and there is some evidence that when states make it hard to opt out of vaccination for non-medical reasons, parents respond by pressuring doctors to write them bogus "medical" excuses.
The root of the problem seems to be that vaccines are victims of their own success. Most people haven't seen the effects of the awful childhood diseases that vaccines have been so effective at eradicating. But they've heard about vaccine reactions, and have heard all the unsubstantiated--or downright fraudulent--claims about vaccines and autism. How many kids will have to suffer or die with whooping cough or measles or pertussis before the public can be persuaded to trust in some of the most reliable science in all of public health?