Number of antigens in early childhood vaccines and neuropsychological outcomes at age 7-10 years

PurposeConcerns 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 7-10years. MethodsChildren aged 7-10years 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 24months 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 24months and domain-specific outcomes. ResultsOn average, children (N=1047) received 7266, 8127, and 10341 antigens by ages 7, 12, and 24months, 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 24months 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). ConclusionsWe 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.