Can Vaccines Trigger Autism?

Abstract

A link between vaccines and autism is increasingly suspected, because vaccines contain neurotoxins and immune suppressants as well as live viruses that could affect a susceptible population. I investigate the possible link by comparing the proportion of children classified with either autism (AUT) or speech or language impairment (SLI) and the proportion of children who received all recommended vaccines by age two in each U.S. state from 2001 and 2005. I find a higher vaccination rate is associated with a higher prevalence of children with autism or SLI. I also examine intra-state data for California and Pennsylvania and find a similar association. Finally, I find that states with a greater proportion of completely unvaccinated children also tend to have lower rates of autism. The results suggest that autism and speech or language impairments could be side effects of vaccination.

Keywords: Health, autism, vaccines

JEL Classification: I10, I12, I18, O15