Background and Aims Concerns about the safety of coronavirus disease 2019 (COVID-19) vaccines in patients with atrial fibrillation/flutter (AF/AFL) have arisen due to reports of thrombo-embolic events following COVID-19 vaccination in the general population. This study aimed to evaluate the risk of thrombo-embolic events after COVID-19 vaccination in patients with AF/AFL. Methods This was a modified self-controlled case-series study using a comprehensive nationwide-linked database provided by the National Health Insurance Service in South Korea to calculate incidence rate ratios (IRRs) of thrombo-embolic events. The study population included individuals aged ≥12 years who were either vaccinated (e.g. one or two doses) or unvaccinated during the period from February to December 2021. The primary outcome was a composite of thrombo-embolic events, including ischaemic stroke, transient ischaemic attack, and systemic thromboembolism. The risk period was defined as 0–21 days following COVID-19 vaccination. Results The final analysis included 124 127 individuals with AF/AFL. The IRR of thrombo-embolic events within 21 days after COVID-19 vaccination, compared with that during the unexposed control period, was 0.93 [95% confidence interval (CI) 0.77–1.12]. No significant risk variations were noted by sex, age, or vaccine type. However, patients without anticoagulant therapy had an IRR of 1.88 (95% CI 1.39–2.54) following vaccination. Conclusions In patients with AF/AFL, COVID-19 vaccination was generally not associated with an increased risk of thrombo-embolic events. However, careful individual risk assessment is required when advising vaccination for those not on oral anticoagulant, as these patients exhibited an increased risk of thrombo-embolic events post-vaccination.

中文翻译：

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心房颤动/扑动中接种 2019 冠状病毒病疫苗后的血栓栓塞：一项自我对照病例系列研究


背景和目的 由于有报道普通人群接种 COVID-19 疫苗后发生血栓栓塞事件，人们对心房颤动/扑动 (AF/AFL) 患者接种 2019 冠状病毒病 (COVID-19) 疫苗的安全性产生了担忧。本研究旨在评估 AF/AFL 患者接种 COVID-19 疫苗后发生血栓栓塞事件的风险。方法 这是一项改良的自我对照病例系列研究，使用韩国国民健康保险服务提供的综合性全国链接数据库来计算血栓栓塞事件的发生率比 (IRR)。研究人群包括年龄≥12岁、在2021年2月至12月期间接种疫苗（例如一剂或两剂）或未接种疫苗的个体。主要结局是血栓栓塞事件的复合，包括缺血性中风、短暂性脑缺血发作和全身性血栓栓塞。风险期定义为接种 COVID-19 疫苗后 0-21 天。结果 最终分析包括 124 127 名 AF/AFL 患者。与未暴露的对照期间相比，COVID-19 疫苗接种后 21 天内血栓栓塞事件的 IRR 为 0.93 [95% 置信区间 (CI) 0.77–1.12]。性别、年龄或疫苗类型没有发现显着的风险差异。然而，未接受抗凝治疗的患者接种疫苗后的 IRR 为 1.88 (95% CI 1.39–2.54)。结论 在 AF/AFL 患者中，接种 COVID-19 疫苗通常与血栓栓塞事件风险增加无关。然而，在建议未服用口服抗凝剂的患者接种疫苗时，需要进行仔细的个体风险评估，因为这些患者在接种疫苗后出现血栓栓塞事件的风险增加。