Myocarditis and Vaccination: Is It Worth the Risk?

Masked teenager at the doctors office.

Scott Yeager, MD, a pediatric cardiologist at University of Vermont Medical Center, answered our top five questions about this rare condition and its connection to COVID-19.

What is myocarditis?

Myocarditis is a general term for inflammation of the heart muscle. The heart can be affected by a variety of things, but the vast majority of myocarditis is felt to be viral in origin. Almost every virus that we've ever identified, including COVID-19, can occasionally cause myocarditis.

How do I know if I am experiencing myocarditis?

Patients with myocarditis may complain of chest pain, shortness of breath, irregular or fast heartbeat or profound fatigue. However, those symptoms may result from COVID-19 infection even if the heart is not involved.  If we are concerned about myocarditis, we can run specific lab tests to determine if the heart has been injured or if the body is demonstrating a very high level of inflammation. Sometimes we use imaging tests like echocardiograms that look at the function of the heart, or MRIs that show any edema or swelling in the heart.

Is myocarditis dangerous?

It depends. If someone comes in with severe symptoms, that could indicate that their heart is very extensively affected, and in that case it could be quite dangerous.

But most of these cases are discovered incidentally after we’ve performed a laboratory test for another reason, and it picks up myocarditis. The vast majority of myocarditis cases are simply going to recover on their own. We don't have any very specific treatment. We primarily provide what we would call supportive care by giving patients anti-inflammatory steroids and other medications to quiet down the inflammation.

Can COVID-19 infection cause myocarditis?

Yes. The COVID-19 virus seems to create myocarditis more commonly than most other viruses.

Are adolescents at risk of myocarditis if they get the COVID-19 vaccine?

This topic has gotten a lot of press and we've received a lot of phone calls about it. But vaccine-related myocarditis is very unusual. The most recent study I saw, published two months ago, collected data from 20 major hospitals. Almost all of the vaccine-related myocarditis cases were male teenagers. All of these patients recovered and nearly all of them had relatively mildly affected hearts. Fewer than 1% of second doses result in this side effect.

The fact is, COVID-19 infection is far, far more likely to lead to a heart problem than the COVID-19 vaccine. And the other risks that come with COVID-19 infection are far, far greater than any risk related to the COVID-19 vaccine.

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