METHODS: We conducted self-controlled case series (SCCS) analysis using the COVID-19 immunization record data from the Korea Disease Control Agency between February 2021 and March 2022, linked with the National Health Insurance Database between January 2021 and October 2022. We retrieved all medical claims of adults aged 18 years or older who received at least one dose of COVID-19 vaccines (BNT162b2, mRNA-1273, ChAdOx1-S, or Ad26.COV2.S), and included only those who had a diagnosis record for encephalitis or meningitis within the 240-day post-vaccination period. With day 0 defined as the date of vaccination, risk window was defined as days 1-28 and the control window as the remainder period excluding the risk windows within the 240-day period. We used conditional Poisson regression to estimate the incidence rate ratios (IRR) with 95% confidence intervals (CI), stratified by dose and vaccine type.
RESULTS: From 129,956,027 COVID-19 vaccine doses administered to 44,564,345 individuals, there were 251 and 398 cases of encephalitis and meningitis during the risk window, corresponding to 1.9 and 3.1 cases per 1 million doses, respectively. Overall, there was an increased risk of encephalitis in the first 28 days of COVID-19 vaccination (IRR 1.26; 95% CI 1.08-1.47), which was only significant after a receipt of ChAdOx1-S (1.49; 1.03-2.15). For meningitis, no increased risk was observed after any dose of COVID-19 vaccine (IRR 1.03; 95% CI 0.91-1.16).
CONCLUSIONS: Our findings suggest an overall increased risk of encephalitis after COVID-19 vaccination. However, the absolute risk was small and should not impede COVID-19 vaccine confidence. No significant association was found between the risk of meningitis and COVID-19 vaccination.
方法:我们在2021年2月至2022年3月期间使用韩国疾病控制机构的COVID-19免疫记录数据进行了自我对照病例系列(SCCS)分析,并与2021年1月至2022年10月期间的国家健康保险数据库相关联。我们检索了18岁或以上接受至少一剂COVID-19疫苗(BNT162b2,mRNA-1273,ChAdOx1-S,或Ad26。COV2.S),并且仅包括在疫苗接种后240天内有脑炎或脑膜炎诊断记录的患者.将第0天定义为疫苗接种日期,风险窗口定义为第1-28天,控制窗口定义为在240天内排除风险窗口的剩余时间.我们使用条件泊松回归以95%置信区间(CI)估计发病率比率(IRR),按剂量和疫苗类型分层。
结果:从给44,564,345个人的129,956,027剂COVID-19疫苗剂量中,在风险窗口期间,有251例和398例脑炎和脑膜炎,相当于每100万剂1.9和3.1例,分别。总的来说,在COVID-19疫苗接种的前28天,脑炎的风险增加(IRR1.26;95%CI1.08-1.47),仅在收到ChAdOx1-S(1.49;1.03-2.15)后才有意义。对于脑膜炎,任何剂量的COVID-19疫苗接种后,风险均未增加(IRR1.03;95%CI0.91-1.16)。
结论:我们的研究结果表明,接种COVID-19疫苗后脑炎的总体风险增加。然而,绝对风险很小,不应妨碍COVID-19疫苗的信心。脑膜炎的风险与COVID-19疫苗接种之间没有显着关联。