Clinical characteristics and mechanism of COVID-19 vaccine-related myocarditis

ABSTRACT

Objective: To investigate the clinical characteristics and potential mechanism of coronavirus disease 2019 (COVID-19) vaccine-related myocarditis. Methods: We made a systematic literature retrieval based on PubMed to search for all reports on COVID-19 vaccine-related myocarditis published by August 31, 2021. A total of 29 reports involving 71 patients with myocarditis were enrolled after screening. The patients' demographic data, vaccination, clinical manifestations, biochemical and imaging results, treatments, and outcomes were extracted and summarized. The patients were divided into prior COVID (n=12) and non-prior COVID (n=59) according to their previous medical history. Results: COVID vaccine-related myocarditis was more common in men (91.5%) and after the second dose of mRNA vaccine (81.7%). The average time to onset was 3 (1, 25) days, and the main symptoms included chest pain (94.4%), fever (45.1%), myalgia (26.8%), and shortness of breath (16.9%). Abnormal troponin level was present in almost all the patients, with a common elevation of C-reactive protein. Non-steroidal anti-inflammatory drugs and colchicine were widely used in clinical treatment, and the symptoms of one-fifth of the patients were relieved after symptomatic therapy, with 1 to 2 weeks' length of hospital stay. However, the risk of vaccine-related myocarditis was significantly increased in patients with previous COVID-19 infection, which was more common after the first dose of vaccine (58.3%) other than the second dose. And the clinical symptoms and outcomes were somewhat different from those without COVID-19 infection previously. Conclusion: Myocarditis is one of the serious adverse events related to COVID-19 vaccine, with an overall relatively low incidence, mild clinical severity, and favorable prognosis. Vaccine-related myocarditis may be a combined result of primed immune system and individual susceptibility after infection with COVID-19.