The Low Risk of COVID-Vaccine-Related Myocarditis and Pericarditis

Observational studies that included millions of participants have been reassuring regarding concerns about vaccine-related myocarditis and pericarditis from COVID-19 vaccines. The risk associated with mRNA vaccines (Pfizer/BioNTech and Moderna) is very low, and there has been no elevated risk detected for adenovirus-based vaccines (Johnson & Johnson).1

Data from an administrative database show that the likelihood of vaccine-related myocarditis is highest among males under age 30, though it is mild and unlikely even in this group.2

Furthermore, vaccine-related myocarditis effects are outweighed by the substantial benefits from preventing COVID-related hospitalizations, ICU admissions and deaths in each age/sex group, even for those at relatively highest risk of vaccine-related myocarditis and lowest risk of COVID-related adverse outcomes. Patient-level data from two large integrated health networks across multiple states confirm a very low incidence of vaccine-related myocarditis (0.5 to 1 case per 100,000 completely vaccinated individuals) and a very mild clinical course.3

Mild, isolated pericarditis has also been observed, occurring among older patients (median 59 years) and at a later time point (median 20 days after most recent vaccine dose).4

Taken together, these data confirm that mRNA-vaccine-associated myocarditis or pericarditis is rare, mild, and self-limited. The substantial benefits of vaccination outweigh the very small risks.


  1. US Centers for Disease Control and Prevention. Clinical Consideratons: Myocarditis and Pericarditis After Receipt of mRNA COVID-19 Vaccines Among Adolescents and Young Adults.
  2. US Centers for Disease Control and Prevention. MMWR. Use of mRNA COVID-19 Vaccine After Reports of Myocarditis Among Vaccine Recipients: Update From the Advisory Committee on Immunization Practices – United States, June 2021.
  3. Simone A, Herald J, Chen A, et al. Acute Myocarditis Following COCID-19 mRNA Vaccination in Adults Aged 18 Years or Older. JAMA Intern Med 2021;Oct 4:[Epub ahead of print].
  4. Diaz GA, Parsons GT, Gering SK, et al. Myocarditis and Pericarditis After Vaccination For COVID-19. JAMA 2021;326:1210-12.

Clinical Topics: COVID-19 Hub, Heart Failure and Cardiomyopathies, Pericardial Disease, Prevention

Keywords: COVID-19 Vaccines, COVID-19, Myocarditis, Adenovirus Vaccines, RNA, Messenger, Data Management, Vaccines, Vaccination, Pericarditis, Hospitalization, Adenoviridae, Intensive Care Units

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