We know that vaccines are highly effective in preventing diseases so much so that those that have been around a long time have been so effective that most people couldn’t imagine having someone in their community with polio or smallpox. The introduction of the vaccines has led to a major decline in the number of children dying before reaching adult, or of reaching adulthood in an impaired state – and the factgs suggest that the vaccines were a major cause.
Given the huge number of people throughout the world using vaccines, if there was a problem we would be seeing a hugh number of people with autism – and that simply isn’t the case. Many have noted that autism does correlate with some other things, such as lower infant mortality (sick kids survive but are impared), older parents, contraception, etc.
Some have suggested increase in diagnosis of “autism” is tied to government benefits given when such a benefit is made and that many kids who might otherwise be considered “normal” were reclassed as “special” to get the handouts. The increase in autism doesn’t appear to be a factor in underdeveloped countries where vaccines are used routinely.