Doctor listening to young boy's heartbeat Whether or not your child has ever been treated for cardiac disease, you’ve probably heard of a condition called myocarditis. Though myocarditis has been around much longer than COVID-19, it’s recently sparked quite a bit of media attention as a very rare side effect of the COVID-19 vaccine. Unfortunately, this means that misconceptions and myths about the condition abound. In order to make an informed decision about vaccinating your child or teen, it’s important to discern the myths from the facts. In the following article, a Children’s Hospital of Philadelphia (CHOP) expert will help you do just that.

What is myocarditis?

Myocarditis is an inflammation of the heart muscle. It can occur when a virus, such as the common cold, influenza (flu) or SARS-CoV-2 (the virus that causes COVID-19) infects the body. Myocarditis can cause chest pain, heart palpitations, difficulty breathing or other symptoms, and it can interfere with heart function. The condition ranges from very mild cases, in which symptoms resolve on their own, or very severe cases, in which a patient requires intensive hospital care, or the heart muscle is permanently damaged.

Myocarditis and the mRNA vaccine

According to the Centers for Disease Control and Prevention (CDC), myocarditis has been identified as a rare side effect of the mRNA vaccine. This side effect is seen much more often in male teens and young adults, as compared to other ages, and is likely due to an exaggerated immune response. Scientists are actively monitoring reports of myocarditis and continuing to learn more about its relationship to the COVID-19 vaccine.

Fortunately, current studies show that post-vaccine-related myocarditis is typically much more mild than classic myocarditis, with symptoms lasting for a shorter amount of time and usually resolving with minimal, if any, medical treatment.

“In classic myocarditis, there are a wide range of presentations, from very mild symptoms to extremely serious, or even fatal, cases,” says Matthew Elias, MD, attending cardiologist in CHOP’s Cardiac Center. “Overall, this does not seem to be happening in post-vaccine myocarditis. In the patients seen at CHOP and at other hospitals, symptoms are generally mild and self-resolving, and heart function is less affected, if affected at all.”

Dr. Elias also notes that patients with post-vaccine myocarditis typically experience a quick recovery, with little to no medical therapy, as opposed to the extensive treatment and possible mechanical support that can be needed in non-vaccine-related myocarditis. 

Weighing the risks

As a parent, it’s natural to feel concerned about any vaccine side effect your child may experience. However, it’s important to weigh the risks of side effects against the risks of infection. In the case of COVID-19, children and teens have a much greater chance of being infected with COVID-19 that results in heart issues, including myocarditis, than experiencing myocarditis as a side effect of the vaccine.

“Though children and teens are fortunately less likely to experience significant heart disease as a result of COVID-19, they can absolutely still develop severe illness, including heart failure and more severe forms of myocarditis,” says Dr. Elias, noting that the biggest concern for children with COVID-19 is the development of multi-system inflammatory syndrome in children (MIS-C), a rare but very serious condition in which different parts of the body — including the heart — become inflamed. “Approximately 50% of patients with MIS-C have decreased heart function,” he says.

Recent data provided by the CDC suggests that among 100,000 vaccinated adolescent males, only about four to seven would be expected to develop post-vaccine myocarditis. If this group was not vaccinated, however, more than 5,500 would be likely to become infected with COVID-19 over a period of three months, with infections resulting in 50 hospitalizations, potential MIS-C, myocarditis and possible death. Recent surges in infections would only increase these risks in unvaccinated individuals.

The numbers are clear: in children and teens, the risk of getting COVID-19, and developing severe illness that could seriously impact the heart, are far greater than the risk of experiencing post-vaccine myocarditis.

Common myocarditis myths busted

Still not convinced? Below, Dr. Elias addresses the most frequent concerns he hears from patient families, and busts common myths about myocarditis and the COVID-19 vaccine.

Myth: The COVID-19 vaccine will cause a child to develop heart disease.

Fact: “Children are much more likely to develop heart issues after COVID-19 infection than after the vaccine. When children develop myocarditis after COVID-19 infection, it’s typically much more severe than when it occurs post-vaccine.”

Myth: Kids don’t get that sick from COVID-19, so they don’t need the vaccine.

Fact: “While kids are less likely to develop severe illness from COVID-19, they can get COVID-19, they can transmit COVID-19 and they can die from COVID-19. Even if they initially have no symptoms with infection, they can still develop MIS-C, which many families haven’t ever heard of.”

Myth: Children with congenital heart disease are at a higher risk of developing post-vaccine myocarditis.

Fact: “Congenital heart disease is not a risk factor for developing post-vaccine myocarditis. However, it has been identified by the CDC as a risk factor for severe infection for COVID-19.”

Take it from Dr. Elias: vaccines are the best way to end the pandemic, keep our kids healthy and get our lives back to normal. “Families often ask whether I would vaccinate my son,” says Dr. Elias. “As soon as the vaccine for kids ages 5-11 was authorized, we took him right in for his first dose. I’ve met and treated patients with post-vaccine myocarditis, COVID-19 myocarditis, and MIS-C, and I had no hesitation. We’ve waited long enough. It’s time to end the pandemic, and vaccines are the way to do it.”

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