no association between receipt of the measles-mumps-rubella (MMR) vaccine and increased risk of autism spectrum disorder (ASD) regardless of whether older siblings had ASD, which might put younger siblings at increased risk of ASD or might make families warier of vaccinating their younger children...
MMR vaccine receipt was defined as having a Current Procedural Terminology (CPT) or ICD-9-CM procedure code indicating receipt of each component (measles, mumps, and rubella) after 1 year of age (eTable 1 in the Supplement). The date of administration of the trivalent MMR (or the last-ad...