My opinion on autism cannot be trusted, because my family is affected.
Disclaiming that, I think there is more than one condition traveling under that name. My grandaughter is on a very strict non-wheat/non-dairy diet. It
absolutely does not cure her, but her condition is vastly worse if she comes off the diet. Responsible research on the diet help, for some kids, is coming out of Uppsala.

Her mother, who teaches Biology, has fallen in and out of the anti-vax trap. In her case, I think it was caused by her personal hit and her Libertarian husband’s crap. We have discussions.