The relationship between the MMR vaccine and autism.
A couple of aspects you may find interesting:
About 90 percent of children in England received MMR at the time this paper was written. Because MMR is administered at a time when many children are diagnosed with autism, it would be expected that most children with autism would have received an MMR vaccine, and that many would have received the vaccine recently. The observation that some children with autism recently received MMR is, therefore, expected.
Perhaps the best data examining when symptoms of autism are first evident are the "home-movie studies". These studies took advantage of the fact that many parents take movies of their children during their first birthday (before they have received the MMR vaccine). Home movies from children who were eventually diagnosed with autism and those who were not diagnosed with autism were shown to blinded eurodevelopmental specialists. Investigators were, with a very high degree of accuracy, able to separate autistic from non-autistic children at one year of age.
These studies found that subtle symptoms of autism are present earlier than some parents had suspected, and that receipt of the MMR vaccine did not precede the first symptoms of autism.