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Symptomatic Acute Myocarditis in Seven Adolescents Following Pfizer-BioNTech COVID- 19 Vaccination

Our take —

This is a case series of seven male patients (14-19 years) who developed myocarditis with or without pericardial inflammation within 4 days of receiving the second dose of Pfizer-BioNTech vaccine in the United States. All patients presented with chest pain, with or without myalgia and/or fever and had elevated cardiac specific enzymes and inflammatory markers and abnormal electrocardiograms. All patients recovered quickly with standard treatments for myo- and pericarditis. While this case series provides detailed descriptions of their clinical presentation and course of treatment, the relationship between the Pfizer-BioNTech vaccine and subsequent cardiac inflammation remains unclear given the following cautions: 1) the lack of adjustment for other factors that may have affected risk for acute cardiac inflammation; 2) the impact of potential selection biases; and, 3) the lack of an appropriate comparison group for evaluating potential risk differences.

Study design

Case Series

Study population and setting

This is a case series of seven adolescent males (14-19 years) hospitalized in the US with acute myocarditis with or without pericardial inflammation (myocarditis/myopericarditis) within four days of receiving their 2nd dose of Pfizer-BioNTech vaccine in April and May 2021. The authors document their presenting symptoms, diagnostic workup, treatment(s), and status at hospital discharge.

Summary of Main Findings

All patients presented to the hospital complaining of chest pain with or without arm pain, myalgia, or fever. Initial evaluation revealed elevated cardiac enzymes (Troponin T, from 1.09 to 22.1) and inflammatory markers (ESR range: 10-40; CRP range: 6.7-18.1) at presentation, All had negative SARS-CoV-2 PCR via nasopharyngeal swap and negative antibodies against SARS-CoV-2 nuclear capsid antigen, six patients had negative other respiratory viral panel and none met criteria for MIS-C.

All patients had evidence of ST segment elevation on their electrocardiogram (ECG); two had evidence of mild ventricular strain and 1 had mildly decreased systolic function on echocardiogram. Myocardial MRIs revealed evidence of myocardial with or without pericardial inflammation in all cases. No evidence of other viral infections were identified in six of the patients as a possible cause for their myocardial inflammation. One patient underwent cardiac catheterization, which revealed normal coronary arteries. Treatment included some combination of IVIG, corticosteroids, and non-steroidal anti-inflammatory drugs (NSAIDs). Three cases resolved with NSAIDs alone. Although 5 hemodynamically stable patients were initially admitted to the intensive care unit for close monitoring, all patients had significant improvement in their symptoms within few days of hospitalization.

Study Strengths

This case series provides detailed information about the presentation, diagnostic workup, treatment, and short-term outcomes among seven adolescents who developed myocardial with or without pericardial inflammation within four days of their second dose of the Pfizer-BioNTech vaccine.


Despite testing for a variety of viral and bacterial infections that could possibly cause myocardial and pericardial inflammation, no mechanistic pathway was examined between Pfizer-BioNTech vaccine and these disorders. Cardiac biopsy was not performed, due to generally mild disease and rapid improvements in clinical status, precluding examining the potential underlying mechanism between Pfizer-BioNTech vaccine and this disorder. Furthermore, as a case study, this paper is not able to assess incidence of myocardial and/or pericardial inflammation after the second dose of the Pfizer-BioNTech vaccine in adolescents or compare incidence against background incidence in this age group. Finally, the cases were identified through personal communications, which may have resulted in significant selection biases if these individuals had other characteristics that affected their risk for acute cardiac inflammation.

Value added

The study provides detailed information on clinical presentation, treatment, and outcomes on male adolescents presenting with myocardial or pericardial inflammation following a second dose of the Pfizer-BioNTech vaccine. This will help pediatricians quickly identify this disorder, provide effective therapy, and encourage health care providers to report these events to the Vaccine Adverse Event Reporting System (VAERS).

This review was posted on: 11 July 2021