Autism Occurrence by MMR Vaccine Status Among US Children With Older Siblings With and Without Autism

Abstract

IMPORTANCE Despite research showing no link between the measles-mumps-rubella (MMR) vaccine and autism spectrum disorders (ASD), beliefs that the vaccine causes autism persist, leading to lower vaccination levels. Parents who already have a child with ASD may be especially wary of vaccinations. OBJECTIVE To report ASD occurrence by MMR vaccine status in a large sample of US children who have older siblings with and without ASD. DESIGN, SETTING, AND PARTICIPANTS A retrospective cohort study using an administrative claims database associated with a large commercial health plan. Participants included children continuously enrolled in the health plan from birth to at least 5 years of age during 2001-2012 who also had an older sibling continuously enrolled for at least 6 months between 1997 and 2012. EXPOSURES MMR vaccine receipt (0, 1, 2 doses) after 1 year of age. MAIN OUTCOMES AND MEASURES ASD status defined as 2 claims with a diagnosis code in any position for autistic disorder or other specified pervasive developmental disorder (PDD) including Asperger syndrome, or unspecified PDD (International Classification of Diseases, Ninth Revision, Clinical Modification 299.0x, 299.8x, 299.9x). RESULTS Of 95 727 children with older siblings, 994 (1.04%) were diagnosed with ASD and 1929 (2.02%) had an older sibling with ASD. Of those with older siblings with ASD, 134 (6.9%) had ASD, vs 860 (0.9%) children with unaffected siblings (P < .001). MMR vaccination rates (Ն1 dose) were 84% (n = 78 549) at age 2 years and 92% (n = 86 063) at age 5 years for children with unaffected older siblings, vs 73% (n = 1409) at age 2 years and 86% (n = 1660) at age 5 years for children with affected siblings. MMR vaccine receipt was not associated with an increased risk of ASD at any age. For children with older siblings with ASD, at age 2, the adjusted relative risk (RR) of ASD for 1 dose of MMR vaccine vs no vaccine was 0.76 (95% CI, 0.48-1.22; P = .25), and at age 5, the RR of ASD for 2 doses compared with no vaccine was 0.56 (95% CI, 0.30-1.04; P = .07). For children whose older siblings did not have ASD, at age 2, the adjusted RR of ASD for 1 dose was 0.91 (95% CI, 0.68-1.20; P = .50) and at age 5, the RR of ASD for 2 doses was 1.09 (95% CI, 0.76-1.54; P = .65). CONCLUSIONS AND RELEVANCE In this large sample of privately insured children with older siblings, receipt of the MMR vaccine was not associated with increased risk of ASD, regardless of whether older siblings had ASD. These findings indicate no harmful association between MMR vaccine receipt and ASD even among children already at higher risk for ASD.

See Me, See My Child

“…In a recent study of 95,727 children with older siblings, receiving the series of MMR vaccines was not associated with increased risk of ASD, even if the younger children were at higher risk because an older sibling had been diagnosed with ASD (Jain et al, 2015).…”

Vaccination Rates among Younger Siblings of Children with Autism

“…2 Although vaccination behaviors were not our primary focus, studies showing decreased rates of vaccination against measles–mumps–rubella (MMR) among high-risk infants prompted us to analyze available data on vaccination behaviors in our sample of 206 families from southern California (71 of which had a child with autism spectrum disorder and 135 that did not have a child with autism spectrum disorder) (Table 1). 3,4 …”

“…These findings are consistent with reported rates of MMR vaccination among children at older ages and across broader sampling regions. 3,4 …”

Progress in pediatrics in 2015: choices in allergy, endocrinology, gastroenterology, genetics, haematology, infectious diseases, neonatology, nephrology, neurology, nutrition, oncology and pulmonology

“…Using an administrative claims database associated with a large US health plan, Jain et al [57] confirmed that measles, mumps and rubella vaccine was not associated with an increased risk of autistic spectrum disorder at any age in 95 727 children. They found that children with an older sibling with autistic spectrum disorder, more frequently develop autistic spectrum disorder, compared with those with siblings without autistic spectrum disorder ( p  < .001).…”