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Vaccinations and Autism

In 1998, Andrew Wakefield and co-workers published an article in The Lancet claiming that the combination measles-mumps-rubella (MMR) vaccine caused autism (see ▶Measles-MumpsRubella (MMR) Vaccination). One year later, following a pointed directive by the United States Public Health Service and the American Academy of Pediatrics (AAP) to remove thimerosal (an ethylmercury-containing preservative) from vaccines, parents became concerned that mercury caused autism. During the next ten years, epidemiological studies showed that both of these hypotheses were incorrect. A few years later, the hypothesis again shifted – this time to the more diffuse and more difficult to test notion that too many vaccines given too early caused autism.While it is unethical to prospectively test children who either have or