Do Vaccines Cause Autism? The Retracted Study and 25 Years of Evidence
False. The 1998 Wakefield study that claimed a vaccine–autism link was found to be fraudulent — the data was manipulated, ethical violations were serious, and the paper was fully retracted. Andrew Wakefield lost his medical licence. Dozens of independent studies covering millions of children find no connection between vaccines and autism.
"Vaccines — particularly the MMR vaccine — cause autism." is a myth. The scientific consensus is clear, the primary sources are documented above, and the claim does not survive scrutiny. Read on for the full evidence.
"Vaccines — particularly the MMR vaccine — cause autism."
No causal link between vaccines and autism has been established. The original claim originated in a fraudulent, retracted paper. Every large independent study conducted since has found no association.
Few medical myths have caused more documented harm than the vaccine–autism claim. Measles outbreaks have returned to countries that had effectively eliminated the disease. Children have died from vaccine-preventable illnesses. And the harm traces back to a single 1998 paper published in The Lancet — a paper subsequently found to be fraudulent, retracted by the journal, and the basis for its author losing his medical licence.
The Origin: The Wakefield Paper
In 1998, Andrew Wakefield and colleagues published a case series of 12 children in The Lancet, suggesting a link between the MMR (measles-mumps-rubella) vaccine, a novel intestinal syndrome, and autism. The paper received enormous media coverage. Subsequent investigations by journalist Brian Deer revealed systematic data manipulation: the children's records showed that their symptoms predated vaccination in most cases, contrary to what the paper reported. Wakefield had also accepted payments from lawyers seeking to sue vaccine manufacturers before the study, creating an undisclosed conflict of interest. He had also applied for patents for competing measles vaccines. The Lancet fully retracted the paper in 2010. The UK's General Medical Council found Wakefield guilty of serious professional misconduct and struck him off the medical register.
What the Evidence Shows
Since 1998, the vaccine–autism hypothesis has been tested in dozens of large, independent studies across multiple countries. A 2019 Danish cohort study following 657,461 children found no association between MMR vaccination and autism diagnosis. A 2020 meta-analysis examining over 1.2 million children across multiple countries found no relationship between any vaccine ingredient (including thimerosal, which was incorrectly cited as a cause) and autism. Studies in Japan, where the MMR vaccine was withdrawn in 1993 due to a mumps strain issue and replaced by separate vaccines, showed that autism rates continued to rise despite the absence of MMR — definitively breaking the proposed temporal link. The scientific and medical consensus is clear, consistent, and unambiguous.
The Thimerosal Claim
After the MMR claim was debunked, a secondary claim emerged targeting thimerosal, a mercury-based preservative used in some multi-dose vaccines (not MMR, which contains no thimerosal). Thimerosal was largely removed from childhood vaccines in the US, EU, and other countries between 1999 and 2001 as a precautionary measure despite no evidence of harm. Autism rates did not decline following this removal — they continued to rise on the same trajectory, further disconfirming the claim. Subsequent studies specifically examining thimerosal exposure found no association with autism.
The Verdict
No credible scientific evidence supports a causal link between any vaccine and autism. The original claim came from a fraudulent, retracted paper. Every large independent study has found no association. The cost of the myth — in preventable illness and death from vaccine-preventable diseases — is measurable and ongoing.
Primary Sources
Frequently Asked Questions
Do vaccines cause autism?
No. The original 1998 paper claiming this was found to be fraudulent and retracted. Dozens of large independent studies covering millions of children across multiple countries find no association between any vaccine and autism.
What happened to Andrew Wakefield?
Wakefield was found guilty of serious professional misconduct by the UK's General Medical Council, including data manipulation, undisclosed conflicts of interest (he was paid by lawyers suing vaccine manufacturers), and ethical violations in his study. He was struck off the UK medical register (lost his licence) in 2010, the same year The Lancet retracted his paper.
Does thimerosal in vaccines cause autism?
No. Thimerosal was removed from most childhood vaccines as a precautionary measure in 1999–2001 despite no evidence linking it to autism. After removal, autism rates continued rising at the same rate, disconfirming the hypothesis. Multiple studies specifically examining thimerosal exposure have found no link to autism.
What causes autism?
Autism spectrum disorder (ASD) has strong genetic components — studies of twins show high heritability. Many genes have been associated with ASD risk. Environmental factors during prenatal development may also play a role. The causes are complex, multiple, and not fully understood. What is well-established is that vaccines are not among them.
What are the risks of not vaccinating?
Unvaccinated individuals are at risk of diseases that are preventable, sometimes serious, and occasionally fatal — measles, whooping cough, meningitis, and others. Communities with reduced vaccination rates experience outbreaks of diseases that had been effectively eliminated. Vaccine-preventable diseases killed approximately 1.5 million children globally in 2021.
How We Verified This Claim
SmartAss Facts evaluates every popular belief against a three-tier source hierarchy: primary sources (peer-reviewed research, government datasets, and institutional reports), secondary sources (reputable journalism citing the primary), and tertiary sources (general reference). Only primary sources are cited.
For this myth — Vaccines — particularly the MMR vaccine — cause autism. — we reviewed the cited primary sources above, cross-referenced against independent scientific literature, and confirmed the verdict with the consensus position of relevant scientific bodies. Last reviewed: 2026-05-25.
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