Cohort studyindependent cross-checkabstract checked★ key study I-SRC-104 in-depth review

MMR vaccine does not cause autism

Measles, Mumps, Rubella Vaccination and Autism: A Nationwide Cohort Study.

Overview

Hviid A et al.. Ann Intern Med 2019 · PMID 30831578 · DOI 10.7326/M18-2101

Among 657,461 Danish children, vaccinated children did not have more autism than unvaccinated ones.

Does the study support the specific claim? No · Methodological quality: high

Study explained simply

What did the researchers want to find out?: Test MMR-autism link
How was the study done?: Nationwide cohort
How many people, animals or samples were studied?: 657,461 children
What was actually found?: No increased autism risk
How large was the observed effect?: HR 0.93 (0.85-1.02)
What do the results mean in everyday life?: Fear of autism is not a reason to avoid MMR
What are the study's limitations?: Observational
What does it say about Elawady's specific claim?: Contradicts banning vaccines
Do the results apply to Germany and Europe?: High

Authors: Hviid A et al.
Journal: Ann Intern Med
Year: 2019
Identifier: PMID 30831578 DOI 10.7326/M18-2101
Verification: verified – PubMed efetch 2026-10-26; Crossref works record checked
Retracted: no
Corrections: none
Extent checked: abstract only
Conflicts of interest and funding: Funded by Novo Nordisk Foundation and Danish Ministry of Health.

Does MMR vaccination increase the risk of autism, including in susceptible subgroups or time windows?

Study design: Cohort study – Nationwide registry-based cohort study
Population: All children born in Denmark 1999-2010
Country: Denmark
Period: Follow-up to 31 August 2013
Sample size: 657,461 children; 5,025,754 person-years; 6517 autism diagnoses
Inclusion and exclusion criteria: Danish-born children followed from age 1

Exposure / intervention: MMR vaccination
Comparator: MMR-unvaccinated children
Endpoints: Autism diagnosis
Statistical methods: Cox regression adjusted for age, birth year, sex, other vaccines, sibling autism, autism risk score

Results: Fully adjusted autism HR for MMR-vaccinated vs unvaccinated 0.93 (95% CI 0.85-1.02). No increased risk in subgroups (sibling history, risk factors, other vaccines) or in time periods after vaccination.
Absolute risks: Incidence 129.7 per 100,000 person-years overall (reported; recalculated in stats/C-SRC-56_vaccines.py).
Authors' conclusion: MMR vaccination does not increase the risk for autism, does not trigger autism in susceptible children, and is not associated with clustering of cases after vaccination.

Orienting tool: ROBINS-E
Type of assessment: simplified assessment (abstract only)
Full formal assessment: no
Overall risk of bias: low
Rationale: Registry data minimise recall and selection bias; residual confounding possible but unlikely to hide harm.

HR CI log-symmetric (0.93; midpoint 0.931). Upper limit 1.02 excludes any meaningful increase.

Removes a common reason given for refusing vaccines (autism).

None of comparable quality.

Directly applicable.

High-quality evidence against a vaccine-autism link.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	high
Risk of bias	low
Precision of results	high
Directness	direct
Reproducibility	replicated
Consistency with the overall evidence	consistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable