I have a cousin in a developing country with autism, who never got vaccination shots as a kid. Also a friend's kid in the same country has measles encephalitis because he never got a shot.
Measles is a horrible disease, and people who propagate against vaccinations are forgetful of the damage it still causes.
The root cause of autism increases is probably overall environmental degradation, the same reason frogs and bees are disappearing.
1'The Crash and Burn of an Autism Guru' - NYT