No link between COVID-19 vaccines and new-onset seizures

Individuals who have been vaccinated against COVID-19 appear to have a risk of new-onset seizure that is similar to that observed among unvaccinated individuals, according to the results of a meta-analysis.

Researchers searched multiple online databases for studies in which seizure occurrence following COVID-19 vaccination was investigated. Meta-analysis was conducted using random- and common-effect models and in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework. Risk of bias in the studies was assessed by the Newcastle–Ottawa Scale.

New-onset seizure incidence, the outcome of interest, was compared among (1) COVID-19 vaccine recipients, (2) unvaccinated cohorts, and (3) various types of COVID-19 vaccines.

Of the 40 studies that met the eligibility criteria, seven were included in the meta-analysis. The total cohort comprised 13,016,024 vaccine recipients and 13,013,262 unvaccinated individuals.

Pooled data showed that the incidence of new-onset seizure (over a 21- or 28-day period after vaccination) did not significantly differ between vaccine recipients and unvaccinated individuals (odds ratio [OR], 0.48, 95 percent confidence interval [CI], 0.19–1.20; p=0.12; I²=95 percent).

Data from four studies accounting for 19,769,004 mRNA vs 47,494,631 viral vector vaccine doses likewise showed no significant difference in new-onset seizure incidence between the two types of COVID-19 vaccines (OR, 1.18, 95 percent CI, 0.78–1.78; p=0.44; I²=0 percent).