This is simply not true. I've talked to a psychologist who treated kids with autism about this. Autism is usually diagnosed at a young age when children develop and also get vaccinated. This leads to bias in some of their parents who are looking for someone or something to blame for their misfortune. Combine this with the fact that in the last two decades diagnostic for autism was extended to other less severe disorders such as Asperger's. If adults would develop autism after getting vaccinated, then it would support this crackpot theory, but they don't.