Based on the Tools for Practice article, “The autism-vaccine story: fiction and deception?” by G. Michael Allan and Noah Ivers. An earlier version of this article appeared in the Canadian Family Physician.
Clinical question
Is there any link between the measles-mumps-rubella (MMR) vaccine and autism?
Evidence
- In 1998, Wakefield and colleagues published a study of 12 children that suggested a link among MMR vaccine, gastrointestinal symptoms, and autism.
- At least 20 higher-quality studies have since failed to show any link between the MMR vaccine and autism.
- A cohort study following more than 500,000 children for a mean of 4 years found no association between MMR vaccination and autism or autistic spectrum disorder.
- A case-control study of 1294 autistic and 4469 non-autistic children found no association with vaccination.
- Time-series analyses reveal no association between the start of MMR immunization and autism, and no association between trends in vaccination rates and autism.
- Canadian research shows no link between MMR vaccination and neurodevelopmental disorders.
- Studies also show no association with the preservative thimerosal, another suggested cause of autism.
Context
The truth about the Wakefield study is as follows:
- The 12 children in the study were carefully selected, and many of their parents already believed MMR vaccination was the cause of their children’s autism.
- Dr. Wakefield had serious undisclosed financial conflicts: he was funded by lawyers involved in lawsuits against immunization manufacturers and was applying for a new vaccine patent.
- In 2004, 10 of the 13 authors retracted their support for the MMR-autism association.
- Britain’s General Medical Council investigation found Wakefield guilty of dishonesty and irresponsibility.
- In 2010, the Lancet fully retracted the Wakefield study.
The legacy of this unfortunate publication includes decreased immunization rates with increased measles rates and continued parental immunization fear.
Bottom line
Convincing evidence from multiple countries shows no association between MMR vaccine (or thimerosal) and autistic disorders. The origins of this controversy incorporate unethical conduct and misleading research.
Implementation
A gap exists between ideal and actual pediatric immunization rates. Meta-analysis of 47 randomized controlled trials showed that patient reminders can increase immunization rates. Adding new babies to a register at first visits and using patient reminders when immunizations are due are effective, feasible, office-based approaches to improving immunization rates. Patient leaflets are available to help address concerns about long-term side effects.
Notes
Dr. Mike Allan is an expert advisor with EvidenceNetwork.ca, an Associate Professor in the Department of Family Medicine at the University of Alberta in Edmonton and the Director of Evidence and CPD with Alberta College of Family Physicians. Dr. Noah Ivers is a family physician at Women’s College Hospital in Toronto, Ont.
Experts available for interview
Mike Allan, MD
University of Alberta
Evidence-based Primary Care Practice
780-248-2057 | 780-342-4038 (clinic) | 780-720-4093 (c) | [email protected]
Stephen Hwang, MD, MPH
St. Michael’s Hospital
Vaccine Safety & Public Health
416-864-5991 | [email protected] | @StephenHwang
John Millar, MD, FRCP(C), MHSc
University of British Columbia
Public Health & Health Policy
604-922-0995 or (c) 604-785-9058 | [email protected] | @JohnMillar10
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