Myopericarditis following mRNA COVID-19 Vaccination in Adolescents 12 through 18 Years of Age.

Objectives To characterize the clinical course and outcomes of children 12 through 18 years of age who developed probable myopericarditis after vaccination with the Pfizer- BioNTech (BNT162b2) COVID-19 mRNA vaccine. Study design A cross-sectional study of 25 children, aged 12 through 18 years, diagnosed with probable myopericarditis following COVID-19 mRNA vaccination as per the CDC criteria for myopericarditis at 8 US centers between May 10, 2021 and June 20, 2021. We retrospectively collected the following data: demographics, SARS-CoV-2 virus detection or serologic testing, clinical manifestations, laboratory test results, imaging study results, treatment and time to resolutions of symptoms. Results Most (88 %) cases followed the second dose of vaccine, and chest pain (100%) was the most common presenting symptom. Patients came to medical attention a median of 2 days (range: Conclusions Our data suggest that symptoms due to myopericarditis following mRNA COVID-19 vaccination tend to be mild and transient. Approximately two thirds of patients underwent CMR, which revealed evidence of myocardial inflammation despite a lack of echocardiographic abnormalities.