Myocarditis after COVID‐19 mRNA vaccination: A systematic review of case reports and case series

Abstract

Background The coronavirus disease of 2019 (COVID‐19) is a global pandemic with over 266 million cases and 5 million deaths worldwide. Anti‐COVID‐19 vaccinations have had exceptional success in subduing the incidence, prevalence, and disease severity of COVID‐19, but rare cases of myocarditis have been reported after COVID‐19 vaccinations. Hypothesis Myocarditis occurring after COVID‐19 mRNA vaccinations have distinguishable clinical characteristics. They usually have a favorable prognosis. Methods We performed a systematic literature search on PUBMED and MEDLINE database from inception to December 5, 2021. Studies were analyzed based on predetermined eligibility criteria. Results A total of 57 studies containing 275 cases of COVID‐19 vaccine‐associated myocarditis were catalogued. Mean age was 26.7 years and male to female ratio was 14:1. For 86.9% of patients, myocarditis occurred after the second dose. Average time to onset and length of hospitalization were 3.7 and 3.9 days, respectively. Prognosis was largely benign, but there was a 1.1% reported mortality. Chest pain (95.2%), elevation of troponin (100%), and ST elevation on electrocardiography (68.5%) were common. Nonsteroidal anti‐inflammatory drugs (81.4%) were the most used medication, followed by colchicine (33.1%). Conclusions Patients with COVID‐19 vaccine‐associated myocarditis are usually younger males presenting with chest pain 3–4 days after receiving their second dose of COVID vaccine. Diagnosis is made by exclusion of all other etiologies. Given significant population benefit from COVID‐19 vaccination, physicians should continue to encourage vaccination while remaining vigilant of the very rare occurrence of myocarditis following COVID‐19 vaccination.

Clinical outcomes of myocarditis after SARS-CoV-2 mRNA vaccination in four Nordic countries: population based cohort study

“…Myocarditis is a rare adverse event after vaccination with the two mRNA vaccines, tozinameran (BNT162b2) and elasomeran (mRNA-1273), against the SARS-CoV-2 virus. The risk seems to be highest in younger age groups, in men, and after the second dose of vaccine, [1][2][3][4][5][6][7][8][9][10] with the number of excess patients with myocarditis per 100 000 men aged 16-24 years after a second dose of a SARS-CoV-2 mRNA vaccine estimated at 5.6 per 100 000 for tozinameran and 18.4 per 100 000 for elasomeran. How the clinical outcomes of myocarditis after vaccination with SARS-CoV-2 mRNA vaccines compare with outcomes after other types of myocarditis, such as myocarditis associated with covid-19 disease and myocarditis not related to covid-19 or vaccination (ie, conventional myocarditis) is unclear.…”

COVID‐19 vaccine induced myocarditis in young males: A systematic review

“…To our knowledge, ours is the largest and most comprehensive review on this topic. Previous systematic reviews on adverse events associated with COVID-19 vaccination focus on describing the clinical course and outcomes of vaccine induced injury gathered from case reports or series 15,16,17 or limit their analysis to reports from vaccine safety surveillance databases. 17 Rather than describing clinical sequalae, ours is the first to summarise the predicted incidence of postvaccine myocarditis across unpublished and published literature.…”

Vaccine‐Triggered Acute Autoimmune Myocarditis: Defining, Detecting, and Managing an Apparently Novel Condition

“…Clinical presentations share yet other strikingly similar features, including sex (overwhelmingly male), young age (more clearly defined when adult cases are studied), when vaccine exposure occurred (within 5 days of a second mRNA vaccine is typical; intriguingly, some data infer that presentations after the first dose can develop if infection with COVID‐19 acts as the first ”vaccine” 10 ), and medium‐term outcomes appear to be overwhelmingly benign. 10 , 11 , 12 , 13 , 14 , 15 …”

“…Overwhelmingly, available data indicate mild, self‐limited clinical disease with clinical and imaging data suggesting fairly complete resolution in most. Reviewing the literature is to be done with caution: the many published case reports and series inevitably include reporting bias, and the several systematic reviews 10 , 11 , 12 , 13 draw from the same pool of published cases, creating a sort of repetition bias. Other sources include safety surveillance, 14 , 17 insurance claims, 18 and national registry databases; these are also likely to underreport milder cases, and a truer disease representation will likely include greater incidence with lower severity.…”