OBJECTIVE: To assess any potential associations between epilepsy and up-to-date vaccination status or cumulative aluminum exposures from vaccines among children under 4 years of age.
STUDY DESIGN: We conducted a case-control study in the Vaccine Safety Datalink (VSD) cohort from 2008 through 2018. Epilepsy cases were identified up to 4 years of age by diagnosis codes with accompanying by antiseizure medication prescriptions. Controls had no diagnosis codes for epilepsy/seizures and no antiseizure medication before 4 years of age. Each case was matched to up to 10 controls. Cases and controls were matched on birthdate, sex, and VSD site. The exposures were age-specific up-to-date vaccination status categories, and continuous, cumulative aluminum content per adjuvant formulation from vaccination. Conditional logistic regression was used to estimate adjusted odds ratios and 95% confidence intervals for the associated risk of epilepsy. Secondary analyses were performed by age subgroups and limited to children with epilepsy of unknown etiology.
RESULTS: The primary analysis included 2,089 cases and 20,139 matched controls. No adjusted odds ratio (aOR) for risk of epilepsy was greater than 1 either for up-to-date immunization status or for cumulative exposure to aluminum per mg increase per adjuvant formulation. In addition, there was no statistically significant relationship in analyses by age group or limitation to children with epilepsy of unknown etiology.
CONCLUSION: Incident epilepsy was not associated with up-to-date vaccination status or cumulative vaccine aluminum exposure among children less than 4 years of age.