Debunking the Supposed Link Between MMR Vaccine and Autism

Robert S. Baltimore, MD reviewing Jain A et al. JAMA 2015 Apr 21. King BH. JAMA 2015 Apr 21.

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.

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.

CITATION(S):

Jain A et al. Autism occurrence by MMR vaccine status among US children with older siblings with and without autism. JAMA 2015 Apr 21; 313:1534. 

King BH.Promising forecast for autism spectrum disorders. JAMA 2015 Apr 21; 313:1518.