Association between the risk of seizure and COVID-19 vaccinations: A self-controlled case-series study.

OBJECTIVE: The risk of seizure following BNT162b2 and CoronaVac vaccinations has been sparsely investigated. This study aimed to evaluate this association. METHOD: Patients who had their first seizure-related hospitalization between February 23, 2021 and January 31, 2022, were identified in Hong Kong. All seizure episodes happening on the day of vaccination (day 0) were excluded, since clinicians validated that most of the cases on day 0 were syncopal episodes. Within-individual comparison using a modified self-controlled case series analysis was applied to estimate the incidence rate ratio (IRR) with 95% confidence intervals (CIs) of seizure using conditional Poisson regression. RESULTS: We identified 1656 individuals who had their first seizure-related hospitalization (BNT162b2: 426; CoronaVac: 263; unvaccinated: 967) within the observation period. The incidence of seizure was 1.04 (95% CI .80-1.33) and 1.11 (95% CI .80-1.50) per 100 000 doses of BNT162b2 and CoronaVac administered, respectively. Sixteen and 17 individuals, respectively, received a second dose after having a first seizure within 28 days after the first dose of BNT162b2 and CoronaVac vaccinations. None had recurrent seizures after the second dose. There was no increased risk during day 1-6 after the first (BNT162b2: IRR = 1.39, 95% CI = .75-2.58; CoronaVac: IRR = 1.19, 95% CI = .50-2.83) and second doses (BNT162b2: IRR = 1.36, 95% CI = .72-2.57; CoronaVac: IRR = .71, 95% CI = .22-2.30) of vaccinations. During 7-13, 14-20, and 21-27 days post-vaccination, no association was observed for either vaccine. SIGNIFICANCE: The findings demonstrated no increased risk of seizure following BNT162b2 and CoronaVac vaccinations. Future studies will be warranted to evaluate the risk of seizure following COVID-19 vaccinations in different populations, with subsequent doses to ensure the generalizability.

Impact of COVID-19 on seizure-related emergency attendances and hospital admissions - A territory-wide observational study.

This is a territory-wide study to investigate the impact of coronavirus disease 2019 (COVID-19) pandemic on Accident and Emergency Department (A&E) attendances and acute ward admissions for seizures. Adult patients who presented to the A&E with seizures from January 23, 2020 to March 24, 2020 (study period) were included and compared with parallel intervals from 2015 to 2019 (control periods). Preexisting time trend in control periods and potential changes during COVID-19 were analyzed by Poisson, negative and logistic regression models. Accident and Emergency Department attendances and ward admissions for seizures decreased significantly during the COVID-19 pandemic. A total of 319 and 230 recorded ward admissions and A&E attendances for seizures were identified during the study period in 2020, compared with 494 and 343 per annum, respectively in the control periods. The ratio of acute ward admission per A&E attendance for seizures did not change significantly. Intensive care utility and mortality rates remained stable. For some patients, delaying medical attention due to fear of nosocomial COVID-19 cross-infection may lead to severe or even life-threatening consequences. This change in medical help-seeking behavior calls for new medical care models to meet the service gap. Education to patients with epilepsy and their caregivers is of utmost importance during this pandemic.

Changes in pediatric seizure-related emergency department attendances during COVID-19 - A territory-wide observational study.

A territory-wide retrospective observational study was conducted in Hong Kong between January 23 to April 22, 2020 to demonstrate changes in pediatric seizure-related accident and emergency department (A&E) visits during the COVID-19 pandemic. Parallel periods from 2015 to 2019 were used as control. All-cause A&E attendances in all paediatric age groups decreased significantly during the study period. Seizure-related attendances decreased across all pediatric age-groups in 2020 (RR 0.379, 95% CI 0.245-0.588), with a disproportionately large decrease in the 0-6 years age group (RR 0.303, 95% CI 0.174-0.526) compared with the 7-18 years age group (RR 0.534, 95% CI 0.393-0.719). Decrease in RTI-related A&E attendances was also more drastic in the 0-6 age group. The two time trends are congruent in the 0-6 years but not the 7-18 years age group. Such a trend is suggestive of the usefulness of infection control measures in seizure prevention, especially amongst young children.