What does the evidence establish about vaccines and autism?
Confidence as of August 4, 2026
3 claims2 open questions
Our take
The paper that started the autism-vaccine claim was retracted. Large studies since have not found a causal link.
Why we say this
The Lancet, 2010
Retracted the 1998 Wakefield paper that claimed an MMR–autism association.
Institute of Medicine, 2004
The body of evidence rejected a causal relationship between MMR vaccine and autism.
U.S. EHR cohort, 2026
In 2.5 million children, the first MMR dose before age 2 was not associated with an autism diagnosis.
This is not a claim of absolute truth. Read the whole story for more context.
as of August 4, 2026
This story tracks the evidence regarding claims that routine childhood vaccines cause autism spectrum disorder. The question became widely public after a 1998 Lancet paper that was later retracted. Subsequent epidemiological studies, systematic reviews, and official health agency assessments have extensively examined the claim.
Where things stand
The original paper proposing a link was retracted and its lead author lost his medical license over research misconduct. Large epidemiological studies and major reviews have not found a causal relationship between vaccines such as MMR and autism, although public concern persists and unrelated claims about other vaccines or ingredients are sometimes discussed separately.
Soon you'll be able to follow a story and get notified when the evidence changes.
Confidence
as of August 4, 2026The strongest artifacts include the retracted Wakefield paper itself, large population studies (including a 2026 U.S. EHR cohort of about 2.5 million children), the Institute of Medicine review, and CDC vaccine safety summaries. These sources do not establish that vaccines cause autism. Claims about specific vaccine components such as thimerosal or newer vaccines may require separate evaluation, but the central MMR-autism hypothesis has been extensively tested and not corroborated.
This is our best read given the published evidence we have reviewed — not a claim of absolute truth.
Open questions
How should rare adverse events be monitored as vaccine schedules change?
Routine surveillance continues even when major causal claims are not supported.
How should public trust be rebuilt when a retracted study had outsized influence?
The history of this claim affects how later vaccine evidence is received.
What would change our mind
- Multiple independent high-quality studies consistently demonstrating a causal relationship between routine childhood vaccines and autism.
- New authenticated evidence showing that major existing reviews systematically misclassified or omitted relevant cases.
Timeline — How we got here
4 updates · append-onlyNew evidenceLarge U.S. EHR cohort finds no MMR–autism link before age 2
Burstain and colleagues analyzed Cosmos electronic health records for more than 2.5 million U.S. children and found no association between receiving the first MMR dose from ages 11.5 to 24 months and a later autism diagnosis — reinforcing earlier epidemiological evidence against an MMR–autism causal link.
Claims & evidence
Each claim is tracked separately — not a single verdict.The 1998 Lancet paper that claimed an association between MMR vaccination and autism was retracted by the journal.
Evidence basis- February 6, 2010Retraction—Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children
The Lancet retracted the paper after an investigation concluded several elements were incorrect.
Large epidemiological studies have not found evidence that MMR vaccination causes autism.
Evidence basis- May 17, 2004Immunization Safety Review: Vaccines and Autism
The review concluded the body of evidence rejected a causal relationship between MMR vaccine and autism.
- Vaccines and Autism: A Summary of the Evidence
CDC summarizes studies showing no link between vaccines and autism.
- August 4, 2026Association between first MMR vaccination before age 2 years and childhood autism in a U.S. EHR cohort of 2.5 million children (Burstain et al.)
In a national retrospective EHR cohort of more than 2.5 million children, receiving the first MMR dose from ages 11.5 to 24 months was not associated with an increased likelihood of an autism diagnosis.
Current evidence establishes that routine childhood vaccines cause autism.
Evidence basis- May 17, 2004Immunization Safety Review: Vaccines and Autism
The review rejected a causal relationship between MMR vaccine and autism.
What this doesn’t establish
Claims commonly associated with this story that the available evidence does not establish. Confirming a narrow fact here is not confirmation of the broader narrative around it. As such, these claims are not included in the claims bar above.
Because the Wakefield paper was retracted, every possible vaccine safety concern about every vaccine is disproved.
Evidence basis- Vaccines and Autism: A Summary of the Evidence
Retraction of one discredited paper does not, by itself, address every distinct vaccine safety question.
Help improve this story
Point us at a source, a mistake, or a framing problem. Every submission is reviewed by a human before anything changes — this is not a vote on what’s true.
Confidence last reviewed August 4, 2026. Updates are append-only; nothing here is edited silently.
Soon you'll be able to follow a story and get notified when the evidence changes.