← Ask your own question

Do vaccines cause autism?

No. The best available evidence, including large systematic reviews and cohort studies involving millions of children, shows no link between vaccines and autism.

This conclusion holds for the MMR vaccine specifically and for childhood vaccines in general, including those that once contained thimerosal.

Strength of evidence

Strong

Multiple Cochrane systematic reviews, a World Health Organization expert committee review, and a U.S. Institute of Medicine review of the epidemiologic literature all reached the same conclusion, based on large cohort and case-control studies covering millions of children.

What the evidence says

No, vaccines do not cause autism. This has been one of the most heavily studied questions in modern medicine, and every major independent review has come to the same answer. A large Cochrane systematic review covering over a million children found that MMR, MMRV, and combined MMR+varicella vaccines did not cause autism or any other serious condition looked at. The World Health Organization's vaccine safety committee likewise concluded that no evidence supports a causal link between the MMR vaccine and autism.

The original fear started with a single 1998 paper suggesting a link between MMR and autism. The Canadian Paediatric Society notes that this report was later found to be fraudulent and was withdrawn by the journal, and that many large studies worldwide have since found no such link.

Autism diagnoses have risen over recent decades, but this reflects broader diagnostic criteria and greater awareness and screening, not vaccination. The American Academy of Pediatrics has stated that more than 40 high-quality studies across seven countries and over 5.6 million people found no connection between vaccines and autism.

You may see a recent U.S. government webpage that questions this consensus. Major pediatric organizations, including the American Academy of Pediatrics, have publicly objected to that change, saying it does not reflect the scientific evidence. The consistent findings from Cochrane, WHO, and decades of independent research remain unchanged: vaccines do not cause autism.

Sources

✓Reviewed by CH, MD, FRCPC

Reviewed by a specialist physician certified by the Royal College of Physicians and Surgeons of Canada, who has read this answer against the sources listed above and confirmed it reflects them. That is not medical advice about your child. How we review

Answer checked July 28, 2026

Educational information only. Not medical advice, not a diagnosis, and no doctor-patient relationship is created by using this. Founded Parent has not examined your child and does not know their history, so this may not apply to you. In an emergency, call your local emergency number. What Founded Parent cannot do

Report a problem with this answer

Related questions

Have a different question? Founded Parent searches published paediatric guidelines and peer-reviewed research, then tells you how strong the evidence actually is.

Ask a question

Educational information only. Not medical advice, not a diagnosis, and no doctor-patient relationship is created by using this. Founded Parent has not examined your child and does not know their history, so its answers may not apply to you. Never delay or disregard advice from a qualified health professional because of something you read here. In an emergency, call your local emergency number.