HealthDay News — Measles, mumps, rubella (MMR) vaccination is not associated with an increased risk for autism, including in children with autism risk factors, according to a study published online March 5 in the Annals of Internal Medicine.
Anders Hviid, DrMedSci, from Statens Serum Institut in Copenhagen, Denmark, and colleagues conducted a nationwide cohort study in Denmark to examine whether the MMR vaccine increases the risk for autism in children. Data were included for 657,461 children born in Denmark from 1999 through December 31, 2010, with follow-up from age 1 through August 31, 2013.
The researchers found that 6517 children were diagnosed with autism during 5,025,754 person-years of follow-up (incidence rate, 129.7 per 100,000 person-years). The fully adjusted hazard ratio for autism was 0.93 when comparing MMR-vaccinated and unvaccinated children (95% confidence interval, 0.85 to 1.02). In subgroups of children defined according to sibling history of autism, autism risk factors, or other childhood vaccinations, or during specified time periods after vaccination, there was no consistently increased risk for autism after MMR vaccination.
“Our study adds to previous studies through significant additional statistical power and by addressing hypotheses of susceptible subgroups and clustering of cases,” the authors write. “We believe that our results offer reassurance and provide reliable data on which clinicians and health authorities can base decisions and public health policies.”
The study was partially funded by the Novo Nordisk Foundation.