Vaccination and Neurodevelopmental Disorders: A Study of Nine-Year-Old Children Enrolled in Medicaid

Results: The analysis of claims data for 47,155 nine-year-old children revealed that: 1) vaccination was associated with significantly increased odds for all measured NDDs [neurodevelopmental disorders]; 2) among children born preterm and vaccinated, 39.9% were diagnosed with at least one NDD compared to 15.7% among those born preterm and unvaccinated (OR 3.58, 95% CI: 2.80, 4.57); and 3) the relative risk of ASD [autism spectrum disorder] increased according to the number of visits that included vaccinations. Children with just one vaccination visit were 1.7 times more likely to have been diagnosed with ASD than the unvaccinated (95% CI: 1.21, 2.35) whereas those with 11 or more visits were 4.4 times more likely to have been diagnosed with ASD than those with no visit for vaccination (95% CI: 2.85, 6.84).

Conclusions: These results suggest that the current vaccination schedule may be contributing to multiple forms of NDD; that vaccination coupled with preterm birth was strongly associated with increased odds of NDDs compared to preterm birth in the absence of vaccination; and increasing numbers of visits that included vaccinations were associated with increased risks of ASD.

link to full study

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