PM1022: Is the Mrna COVID-19 Vaccine Safe in Patients with a Prior History of Myocarditis?

Background: The mRNA COVID-19 vaccines (BNT162b2 and mRNA-1273) have demonstrated efficacy in reducing COVID-19 hospitalizations and deaths. There have been numerous reports linking these vaccines to subsequent development of myocarditis. However, given the relatively benign course of vaccine induced myocarditis and the clear benefits of vaccination, the Centers for Disease Control and Prevention has recommended continued use of these vaccines. To date, there have been no reports highlighting the safety of mRNA COVID-19 vaccines in children and adults with a prior history of myocarditis, which was the aim of our study.

Methods: We included all children and adults cared for at The Cleveland Clinic Children’s who had a history of myocarditis (clinical or confirmed by cardiac magnetic resonance imaging [MRI] or endomyocardial biopsy) prior to the COVID-19 pandemic (prior to 2020) AND had subsequently received at least two doses of either of the mRNA COVID-19 vaccines. Patients’ charts were reviewed and participants were contacted by phone to obtain demographic and clinical information.

Results: A total of 34 patients met our inclusion criteria. Median age was 41 years, majority male (23, 67.6%) and White (29, 85.3%). Most had their initial episode of myocarditis as adults (30, 88.2%); majority (27, 79.4%) received the BNT162b2 vaccine; 26 patients (76.5%) had received 3 doses of vaccine. Only 1 patient had recurrence of myocarditis confirmed by cardiac MRI after receiving the second dose. He was a White male, who had his first episode of myocarditis at age 20 and was 27 years old at the time of recurrence. He developed chest pain two days after receiving the mRNA-1273 vaccine and had elevated troponin (peak troponin 0.268 ng/ml) and cardiac MRI showed normal biventricular size and function, but with sub-epicardial delayed enhancement involving the basal inferolateral and inferior wall and distal lateral segment without increased myocardial signal intensity on T2 imaging (Figure). Hospital course was short and benign without need for any cardiac support and six weeks post-discharge no issues were noted.

Conclusion: While there have now been numerous reports of myocarditis post-mRNA vaccination, to our knowledge this is the first report of mRNA COVID-19 vaccines in children and adults with a prior history of myocarditis. We concluded that the risk of recurrence of myocarditis after receiving mRNA COVID-19 vaccine is extremely low. In the single patient in our study that had recurrence, the course was very benign highlighting that it is important to continue to emphasize that the risk of developing myocarditis from the COVID-19 is significantly higher than from mRNA vaccination. While large scale studies are needed to confirm our findings, our study will be valuable to clinicians in the interim while discussing risk-benefit ratio of vaccinations in those with a prior history of myocarditis.