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Immunization Science

Autism and age at first MMR vaccination

The article

Age at First Measles-Mumps-Rubella Vaccination in Children With Autism and School-Matched Control Subjects: A Population-Based Study in Metropolitan Atlanta. DeStefano F, Karapurkar Bhasin T, Thompson WW, Yeargin-Allsopp M, and Boyle C. Pediatrics 2004;113: 259-266

The question

Are children vaccinated at an earlier age with the measles-mumps-rubella (MMR) vaccine at a higher risk of developing autism than children vaccinated at a later age?

The study

This study examined the hypothesis that earlier age at vaccination (for example, before the time at which autism starts to develop) might be associated with an increased risk for autism.

Researchers compared the immunization records of 625 children diagnosed with autism with 1824 non-autistic (control) children of the same age, gender, and school in metropolitan Atlanta. They looked for significant differences in the age at the first MMR vaccination between the two groups.

The findings

In general, children in both groups were vaccinated with MMR at the same age. Most children with autism (70.5%) and control children (67.5%) were vaccinated between 12 and 17 months of age. Similar proportions of case and control children had been vaccinated before 18 months or 24 months. Also, no age associations were found for specific subgroups of children with autism.

“Similar proportions of case and control children were vaccinated by the recommended age or shortly after (ie, before 18 months) and before the age by which atypical development is usually recognized in children with autism (ie, 24 months),” the researchers wrote. “Vaccination before 36 months was more common among case children than control children, especially among children 3 to 5 years of age, likely reflecting immunization requirements for enrollment in early intervention programs.”

The relevance/bottom line

This study shows that age at first vaccination with MMR is not associated with a higher risk of developing autism.

NNii’s comments

Measles, German measles and mumps are serious diseases that can be prevented by immunization. There is no evidence that MMR vaccine causes ASD.