Immediate and 6-month seizure outcomes following first and second SARS-CoV2 mRNA vaccinations: A multicenter study with a nationwide survey.

Objective: This study aimed to identify seizure outcomes in people with epilepsy (PWE) following severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) messenger RNA vaccination.

Methods: We examined PWE (n = 332, age ≥ 14 years) treated in four tertiary hospitals between 2021 and 2022 to assess the incidence of seizure worsening following vaccination using closed questions. We identified the clinical factors associated with worsening and 6-month vaccination outcomes. We also conducted a nationwide survey on self-reported seizure worsening using open questions, to which 261 general practitioners from 99 institutes contributed.

Results: Of the 282 PWE vaccinated in the four hospitals, 16 (5.7%) exhibited seizure worsening; most of them emerged within 48 h of vaccination and were not sustained. Thus, all PWE were at baseline condition 6 months after their vaccination. PWE with seizure worsening were more significantly associated with focal impaired awareness seizures (p < 0.001), high seizure frequency (p = 0.025), and drug-resistant epilepsy (p = 0.007) at baseline compared to PWE without worsening. Multivariate logistic regression analysis revealed that focal impaired awareness seizures were independently associated with worsening (odds ratio, 7.0; 95% confidence interval, 1.50-32.77). A nationwide survey of 5156 PWE data (real-world data) confirmed an extremely low incidence rate of self-reported seizure worsening (0.43%).

Significance: Some PWE, particularly refractory focal epilepsy, exhibit seizure worsening. However, the worsening events were infrequent, non-sustainable, and probably under-reported by PWE, suggesting that there is little evidence that worsening seizures discourage current and future vaccinations.