Abstract TMP11: Cerebral Venous Sinus Thrombosis After Covid-19 Vaccination In Korea: A Nationwide Cohort Study

Introduction: Covid-19 vaccination is reported to relate with cerebral venous sinus thrombosis (CVST). This study aims to evaluate the association between CVST and Covid-19 vaccination in Korea. Methods: Hospitalized patients with incident CVST during January 2021 to January 2022 were extracted from nationwide health insurance claim data, and the history of vaccination was investigated. We used modified self-controlled case series (SCCS) analysis comparing the occurrence of CVST between risk period (within 28 days of covid-19 inoculation) and control period (excluding the risk period) and calculated the incidence rate ratio (IRR) for CVST in risk period compared to control period. Sensitivity analysis with extended risk period up to 5 weeks was also performed. Results: A total of 373 CVST cases were recruited in this SCCS study. The IRR for CVST in risk period was 1·41 (95% CI 1·01-1.95) compare with a control period. Subgroup analysis according to demographic profile revealed IRR of 1.86(1.01-3.42) and 2.53(1.40-4.58) in the age of 30-49 and 50-64 respectively, and also significantly higher IRR of 1.84(1.14-26.96) in women. CVST without thrombocytopenia group showed similar IRR of 1.45 (1.04-2.01). In the sensitivity analysis with risk period extended to 5 weeks, the IRR was 1.55 (1.13-2.13), which was not significantly different to 4 weeks risk period. Conclusions: A significant increase in the risk of cerebral venous thrombosis after COVID-19 vaccination is suggested from this study. The risk was higher in the old age and women. Because our data is health insurance claim data, the risk might be overestimated, and the validation of diagnostic accuracy is scheduled. Also nationwide registry of confirmed CVST cases will be presented and compared. Despite these limitation, this study heralds that CVST could follow after Covid-19 vaccination. Funding: This study was funded by research grant from Korean Center for Disease Conttrol, National Academy of Medicine in Korea, and Korean Stroke Society.