title: Number of antigens in early childhood vaccines and neuropsychological outcomes at age 7-10 years.
abstract: OBJECTIVE
  Concerns have been raised that children may be receiving too many immunizations under the recommended schedule in the USA. We used a publicly available dataset to evaluate the association between antibody-stimulating proteins and polysaccharides from early childhood vaccines and neuropsychological outcomes at age 7-10 years.
  
  
  METHODS
  Children aged 7-10 years from four managed care organizations underwent standardized tests for domain-specific neuropsychological outcomes: general intellectual function, speech and language, verbal memory, attention and executive function, tics, achievement, visual spatial ability, and behavior regulation. Vaccination histories up to 24 months of age were obtained from medical charts, electronic records, and parents' records. Logistic regressions and structural equation modeling (SEM) were used to determine associations between total antigens up to 7, 12, and 24 months and domain-specific outcomes.
  
  
  RESULTS
  On average, children (N = 1047) received 7266, 8127, and 10 341 antigens by ages 7, 12, and 24 months, respectively. For adjusted analyses, increase (per 1000) in the number of antigens was not associated with any neuropsychological outcomes. Antigen counts above the 10th percentile, compared with lower counts, were also not associated with any adverse outcomes. However, children with higher antigen counts up to 24 months performed better on attention and executive function tests (odds ratio for lower scores = 0.51, 95% confidence interval = 0.26, 0.99). Similar results were found with SEM analysis (b = 0.08, p = 0.02).
  
  
  CONCLUSIONS
  We did not find any adverse associations between antigens received through vaccines in the first two years of life and neuropsychological outcomes in later childhood. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
authors.affiliation: Immunization Safety Office, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Shahed
authors.initials: S
authors.lastname: Iqbal
authors.forename: John P
authors.initials: JP
authors.lastname: Barile
authors.forename: William W
authors.initials: WW
authors.lastname: Thompson
authors.forename: Frank
authors.initials: F
authors.lastname: DeStefano
mesh_terms: D000941:Antigens / Q000032:analysis* / Q000276:immunology; D002648:Child; D006801:Humans; D007115:Immunization Schedule; D016015:Logistic Models; D008606:Mental Processes; D008961:Models, Structural; D009483:Neuropsychological Tests; D014611:Vaccination / Q000592:standards* / Q000706:statistics & numerical data; D014612:Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000941:Antigens; D014612:Vaccines
keywords: antigens; child health; epidemiology; neuropsychology; pediatrics; pharmacoepidemiology