researchers are taking a close look at rare cases of inflammation of the heart muscle, or myocarditis, in young men who developed symptoms shortly after receiving the second dose of the Moderna or Pfizer messenger RNA (mRNA) COVID-19 vaccines. Several recent studies suggest that health care professionals should watch for hypersensitivity myocarditis as a rare adverse reaction to being vaccinated for COVID-19. However, researchers stress that this awareness should not diminish overall confidence in vaccination during the current pandemic.
While reports of post-vaccine myocarditis in some areas are higher than baseline, the imminent and greater risk for heart damage and death continues to be from becoming infected with COVID-19. Up to 60% of people who are seriously ill with COVID-19 experience injury to their heart, and nearly 1% of fit athletes who had a mild COVID-19 infection show myocarditis on an MRI.