I don't know what community you're talking about or the autism rate there. Since the rate of autism according to Wikipedia is about 0.1-0.2%, in a population of 40k random people you'd expect, on average, to find 40-80 autistic people. Of course, not every group is random and you will definitely see variations (which are especially noticeable at the extreme ends such as a disease that affects a tenth of a percent of the population). Autism appears likely to be linked to genetics, especially since 4.3 males have it for every female. Given that males are much more likely to have genetic issues because they lack two X chromosomes, that explanation would make sense. I don't see 4.3 males getting vaccinated for every female getting vaccinated.