Debunking the Supposed Link Between MMR Vaccine and Autism

May 6, 2015

Debunking the Supposed Link Between MMR Vaccine and Autism

  1. Robert S. Baltimore, MD

In a large cohort, measles-mumps-rubella vaccination was not associated with increased risk for autism spectrum disorders, even in children who had older siblings with such disorders.

  1. Robert S. Baltimore, MD

Many people believe that receipt of measles-mumps-rubella (MMR) vaccine is associated with increased risk for autism spectrum disorders (ASD), despite substantial research demonstrating that such a link does not exist. Children who have older siblings with ASD might be less likely to receive this vaccine than those whose older siblings are not so affected, because of increased parental fear that they, too, will develop ASD. Now, researchers have performed a large retrospective cohort study to determine whether ASD was more common in children who were immunized with MMR than those who did not receive the vaccine.

Using data from a large U.S. commercial health plan, the investigators identified 95,727 children enrolled in the plan who had an older sibling also enrolled. ASD was diagnosed in 994 (1.04%) of these children during follow-up. Of the 1929 children who had an older sibling with ASD, 134 (6.9%) developed ASD, compared with 860 (0.9%) of the 93,798 children with unaffected older siblings (P>0.001), suggesting a familial component in the risk for ASD. MMR vaccination rates (≥1 dose) were substantially higher, both at 2 years and at 5 years, in children with unaffected siblings than in those with affected ones (84% vs. 73% and 92% vs. 86%, respectively). Receipt of MMR vaccine was not associated with increased risk for ASD at any age, regardless of whether older siblings had ASD.

Comment — Infectious Diseases

I agree with these investigators, who conclude that MMR was not associated with increased risk for ASD — even among children already at greater risk because of having an older sibling with ASD. As noted in the accompanying editorial, despite many theories, we don't know the etiology of ASD.

Comment — Psychiatry

  1. Barbara Geller, MD

Ironically, prenatal rubella is associated with a very high incidence of ASD, estimated at 7% of affected toddlers (J Pediatrics 1978; 93:699). Thus, if the currently unvaccinated female children do not later receive rubella protection, they will be vulnerable to prenatal rubella and their offspring will be at high risk for ASD. Regrettably, it may take such data (from cases of rubella-related autism in the future) to convince parents to vaccinate their children. Although rubella has recently been eliminated in the U.S., imported cases from countries with active disease could trigger an outbreak similar to the recent measles outbreak stemming from an imported measles case.

Editor Disclosures at Time of Publication

  • Disclosures for Robert S. Baltimore, MD at time of publication Editorial boards Current Opinion in Pediatrics; Infectious Diseases in Children Leadership positions in professional societies Member Committee on Rheumatic Fever, Endocarditis and Kawasaki Disease


Reader Comments (1)

Roberta Kline MD Physician, Other

Many limitations of this study, including the retrospective nature, and limiting it to children using the same plan for 5 years. Until these studies look at the underlying genomics playing a role in detoxification of the chemicals in the vaccines, none of these studies can be applied to an individual wanting to know the risks and benefits of current vaccines. Genomic SNPs in many pathways are known to be associated with increased risk of ASD and other neurodevelopmental disorders, and environmental exposures are critical. For many, it is the total burden of so many vaccines that overwhelms the system.

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