Ivy, thank you for the excellent points you brought up regarding the misinformation about autism spectrum disorder (from mercury poisoning, to MMR vaccination, to blah blah blah). It reminds me of Jenny McCarthy's ridiculous statement of how she CURED HER SON OF AUTISM.
One big recent issue surrounding vaccinations was due to the possible linkage between Thiomersal (a preservative for vaccines) and development of autistic-like symptoms. This has been negated as a linkage of causation becauase ASD is not a mitochondrial disorder, hence, there is no logic of why thiomersal would be an issue.
Also, like Lux said, the rate of increase in diagnosis is because today, unlike 50 years ago, there is hella lot more awareness about the disorder, as well as, more refined diagnosing techniques.
Finally, another excellent point by Ivy, is the "herd immunity". Those who are opting out of vaccinations for their children, of course, it is their right to do so, but, they are relying implicitly on the rest of the herd to be healthy, hence, x, y, z disease is not a likely concern for them.
If everyone stopped getting the vaccines, then, the concern for x, y, z disease as a real possibility in a given population increases exponentially and significantly (p=0.05), given the likelihood of exposures, rate of cross-infection, incubation period, success rate of treatment being inverse (lower) than rate of cross-infection & incubation (containment of disease). A very real issue is also the general population's comparatively weak immune system, than say, someone in West Africa. Because we're too "clean".
I am quite skeptic of those who say they get "informed" about vaccines and to what degree their knowledge acquisition is from valid sources versus hype.
For example, the program for the HPV vaccination in Canada for young girls, given what I know of it so far, wouldn't recommend.
Not all vaccinations = good. It's about the process of getting informed, and, as a reaction to the hype FOR vaccination, not falling into the trap of going to the opposite spectrum, by falling into the hype AGAINST vaccination.