MMR vaccine receipt was defined as having aCurrent Procedural Terminology(CPT) orICD-9-CMprocedure code indicating receipt of each component (measles, mumps, and rubella) after 1 year of age (eTable 1 in theSupplement). The date of administration of the trivalent MMR (or the last-administered...
This observational cohort study reports no association between the MMR vaccine and autism spectrum disorder among US children with older siblings with