Autism and Vaccines

Approved by Council on March 14, 2016

Vaccines work with the immune system to prevent infectious diseases like polio, measles, diphtheria, and whooping cough. As such, vaccines are one of the greatest success stories in all of medicine. Unfortunately, immunization rates have dropped in recent years in part because of concerns about whether some vaccines may be associated with autism.

Years ago, some people questioned whether the onset of characteristic symptoms of autism coincided with the timing of immunizations. Since then, multiple studies conducted in several different countries have demonstrated that there is no causal association between vaccines and autism. Neither vaccines nor their preservatives increase the rate of autism compared to unvaccinated children. Vaccines do not change the timing of autism symptoms, nor is there any effect on autism severity. Even in families at greater risk for autism, for example, where there is already a child with autism, there is no increase in the likelihood that the second child will have autism if he or she is vaccinated. Recent studies have also demonstrated that brain changes associated with autism risk most likely occur before birth and well before any immunizations are ever administered.

On the other hand, the consequences of measles, diphtheria, whooping cough, and other preventable diseases can be catastrophic. As immunization rates in the population fall, the risks of these diseases become more and more significant.

AACAP continues to support efforts to ensure that all children receive appropriate immunizations.

  • Age appropriate vaccinations are safe and may prevent serious illnesses.
  • There is no evidence to support any link between vaccinations or their preservatives and autism.
  • Research in the potential causes of autism, particularly possible environmental risk factors, should continue to be a priority.


Centers for Disease Control (CDC). Vaccines Do Not Cause Autism. Accessed on 29 February, 2016, at:

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Schechter R, Grether JK. Continuing increases in autism reported to California’s developmental services system: Mercury in retrograde. Arch Gen Psychiatry. 2008;65:19-24.

Taylor B, Miller E, Farrington CP, et al. Autism and measles, mumps, and rubella vaccine: no epidemiological evidence for a causal association. Lancet. 1999;353(9169):2026-2029.

Taylor LE, Swerdfeger AL, Eslick GD. Vaccines are not associated with autism: An evidence-based meta-analysis of case-control and cohort studies. Vaccine. 2014 June;32(29):3623–3629.