Background

Reports have suggested an association between the development of myocarditis and the receipt of messenger RNA (mRNA) vaccines against coronavirus disease 2019 (Covid-19), but the frequency and severity of myocarditis after vaccination have not been extensively explored.

Methods

We searched the database of Clalit Health Services, the largest health care organization (HCO) in Israel, for diagnoses of myocarditis in patients who had received at least one dose of the BNT162b2 mRNA vaccine (Pfizer–BioNTech). The diagnosis of myocarditis was adjudicated by cardiologists using the case definition used by the Centers for Disease Control and Prevention. We abstracted the presentation, clinical course, and outcome from the patient’s electronic health record. We performed a Kaplan–Meier analysis of the incidence of myocarditis up to 42 days after the first vaccine dose.

Results

Among more than 2.5 million vaccinated HCO members who were 16 years of age or older, 54 cases met the criteria for myocarditis. The estimated incidence per 100,000 persons who had received at least one dose of vaccine was 2.13 cases (95% confidence interval [CI], 1.56 to 2.70). The highest incidence of myocarditis (10.69 cases per 100,000 persons; 95% CI, 6.93 to 14.46) was reported in male patients between the ages of 16 and 29 years. A total of 76% of cases of myocarditis were described as mild and 22% as intermediate; 1 case was associated with cardiogenic shock. After a median follow-up of 83 days after the onset of myocarditis, 1 patient had been readmitted to the hospital, and 1 had died of an unknown cause after discharge. Of 14 patients who had left ventricular dysfunction on echocardiography during admission, 10 still had such dysfunction at the time of hospital discharge. Of these patients, 5 underwent subsequent testing that revealed normal heart function.

Conclusions

Among patients in a large Israeli health care system who had received at least one dose of the BNT162b2 mRNA vaccine, the estimated incidence of myocarditis was 2.13 cases per 100,000 persons; the highest incidence was among male patients between the ages of 16 and 29 years. Most cases of myocarditis were mild or moderate in severity. (Funded by the Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute.)

中文翻译：

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大型医疗机构接种 Covid-19 疫苗后的心肌炎

背景

报告表明，心肌炎的发展与接受针对 2019 年冠状病毒病 (Covid-19) 的信使 RNA (mRNA) 疫苗之间存在关联，但尚未广泛探讨疫苗接种后心肌炎的发生频率和严重程度。

方法

我们在以色列最大的医疗保健组织 (HCO) Clalit Health Services 的数据库中搜索了至少接受过一剂 BNT162b2 mRNA 疫苗 (Pfizer–BioNTech) 的患者的心肌炎诊断。心肌炎的诊断是由心脏病专家使用疾病控制和预防中心使用的病例定义做出的。我们从患者的电子健康记录中提取了表现、临床过程和结果。我们对第一次接种疫苗后长达 42 天的心肌炎发病率进行了 Kaplan-Meier 分析。

结果

在超过 250 万名 16 岁或以上接种疫苗的 HCO 成员中，54 例符合心肌炎标准。每 100,000 人中至少接种一剂疫苗的估计发病率为 2.13 例（95% 置信区间 [CI]，1.56 至 2.70）。据报道，16 至 29 岁男性患者的心肌炎发病率最高（每 100,000 人 10.69 例；95% CI，6.93 至 14.46）。总共 76% 的心肌炎病例被描述为轻度，22% 为中度；1例合并心源性休克。在心肌炎发作后中位随访 83 天后，1 名患者再次入院，1 名患者出院后不明原因死亡。在入院期间超声心动图显示左心室功能不全的 14 名患者中，10人出院时仍有此类功能障碍。在这些患者中，有 5 人接受了随后的检查，结果显示心脏功能正常。

结论

在以色列大型医疗保健系统中至少接种一剂 BNT162b2 mRNA 疫苗的患者中，心肌炎的估计发病率为每 100,000 人 2.13 例；发病率最高的是16至29岁的男性患者。大多数心肌炎病例的严重程度为轻度或中度。（由哈佛医学院和 Clalit 研究所的 Ivan 和 Francesca Berkowitz 家庭生活实验室合作资助。）