Does COVID-19 Vaccine Cause Myocarditis?
Vaccines are used to prevent or reduce the seriousness of COVID-19 infection from the SARS-CoV-2 virus. In 2021-22 there were reports of myocarditis occurring shortly after receiving the vaccination.
What is myocarditis?
Myocarditis is the sudden inflammation of the muscle tissue of the heart. There are 4 to 14 cases per 100,000 people worldwide every year. Causes of myocarditis include viral infections, autoimmune diseases, and receiving certain vaccines. Myocarditis is estimated to be fatal in 1 to 7% of those people affected by the condition.
Is the COVID-19 vaccine associated with myocarditis?
Myocarditis was noted in 38 cases per million doses after the second dose of the original vaccine in 2020-2021 and in approximately 25 cases per million doses after original monovalent booster doses in 2021-2022. Cases were reported most frequently in white, male patients 16 to 30 years of age.
In those diagnosed with vaccine associated myocarditis, it was found to be a mild disease, with about 80% of patients fully recovered within 3 months after myocarditis was diagnosed.
What has changed in recent years?
Since the initial COVID-19 vaccines were developed in 2020, the manufacturers have updated the product formulations, including to protect against newer virus variants (changes in the virus). Monitoring of COVID-19 vaccine related myocarditis for the 2022-23, 2023-24, and 2024-2025 seasons found no significant increased risk in people 12-39 years of age or in other age groups.
Is the SARS-CoV-2 virus associated with myocarditis?
Yes! Infection with the SARS-CoV-2 virus has been associated with increased rates of myocarditis. Overall, one study reported that SARS-CoV-2 infection caused 150 cases per 100,000 of myocarditis compared to 9 cases per 100,000 in non-COVID-19 related cases in 2020-2021.
What are the risks and benefits to consider?
It is important to know that infection with the SARS-Co-V-2 virus that causes COVID-19 also carries an increased risk of myocarditis and often results in more serious cardiovascular effects. The reduction of serious disease and hospitalizations in those receiving COVID-19 vaccination continues to be confirmed in research.
Summary
Initially some people (e.g., young men) were noted to have higher incidence of myocarditis after injection with the initial COVID-19 formulations but continued monitoring has found this to no longer be the case with use of current vaccine formulations. Because the risk of myocarditis is increased after infection with the SARS virus, it is important to receive the most current COVID-19 formulation to prevent disease associated with the virus.