Myocarditis and other heart conditions have been associated with COVID-19 infections and vaccines. In this article, I will introduce some information on the topic - for those interested in learning more please see the website listed at the end of this article.
Myocarditis is not a single disease but more of a general term describing a process. Myocarditis is inflammation of the heart muscle. Pericarditis is an inflammation of the membrane that surrounds the heart. Sometimes people can have both conditions. The conditions sometimes are lumped together in studies and discussions about this topic. For this article I will refer to “myocarditis” but much of what can be said about myocarditis also applies somewhat to pericarditis.
Most people with myocarditis will only have mild symptoms with no long-term problems; however, serious complications such as heart failure can develop and in rare instances people have died. The severity of the condition depends on factors including what caused the heart inflammation. There have been dozens of infectious and non -infectious causes identified for myocarditis. Medications including common antibiotics have been linked to myocarditis. Conditions such as inflammatory bowel disease have been associated with myocarditis as well as infections. In the United States viruses are thought to be the most common causes of myocarditis.
Over 20 different viruses including SARS-CoV-2 have been identified as probable causes of myocarditis. On autopsies, SARS-CoV-2 has been found only in a small percentage of hearts. Samples obtained from the hearts of people who have died of COVID-19 have shown a variety of other types of heart problems other than myocarditis. How the virus can cause myocarditis is still being studied - it is not clear how often myocarditis and other heart problems are from the virus directly infecting the heart or from other mechanisms. A number of analyses have looked at how often the heart is damaged from COVID-19 including studies of young athletes. Refer to the article “COVID-19 Cardiovascular Consequences” for more information.
Vaccine surveillance systems last year picked up a signal that the mRNA vaccines might be causing myocarditis. Many studies and analyses have since looked at the prevalence and severity of myocarditis after vaccination.
A review article of 11 studies on vaccination and myocarditis was published at the end of September. I will include in the supplemental information a link to the full article. The authors of the review article concluded that while not common there was an elevated risk of myocarditis after vaccination with an mRNA vaccine, most notably in those under 40 years of age. The risk was higher after the second dose of an mRNA vaccine (Moderna may be slightly higher risk than Pfizer-BioNTech). The authors of the study pointed out that the health risks associated with vaccination are significantly lower than getting COVID-19.
Another review article specifically looks at the risk of myocarditis following vaccination versus infection. This systematic review and meta-analysis of data conducted by the Penn State College of Medicine was published at the end of August. They concluded from analyzing 22 studies with data from 58 million individuals “the relative risk of developing myocarditis was more than 7 times greater among those with a COVID-19 infection than those who underwent vaccination”. It is also important to know that myocarditis after vaccination is usually mild and most have fully recovered.
The timing of the second dose of an mRNA vaccine seems to impact the risk of developing myocarditis. In February, a panel of vaccine experts recommended extending the interval of time between first and second doses of an mRNA vaccine in those most at risk for developing myocarditis. An interval of 8 weeks between doses has been suggested for males between the ages of 12 and 39 years of age.
Myocarditis is a rare complication of COVID-19 mRNA vaccines. Myocarditis and other health problems are far more common with getting COVID-19. If you have questions about getting vaccinated against COVID-19 please make an appointment with your primary care provider.
All statements in this article should be attributed to myself, not any organization I represent or my employer. This article presents a medical perspective - not a statement intended to be for or against any public policy or politician.
For references and more information go to:
Russ Coash, PA-C
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