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Our primary care doctors in Jupiter have been receiving worried calls from parents about the possibility of their children contracting myocarditis and pericarditis from the COVID-19 vaccine.

We’d like to reassure you that the possibility is remote. Here are the facts.

The condition

Myocarditis is inflammation of the muscle of the heart. A related condition, pericarditis, is inflammation of the tissue that forms a sac around the heart. Either one is an indication of the body’s immune system responding to an infection or some other trigger.

This relatively rare condition can occur with many types of infections, especially viruses, including COVID-19. It can also occur with heavy metal poisoning, radiation treatments, some medications, and autoimmune conditions such as rheumatoid arthritis.

It also can occur after certain vaccinations, like smallpox. Now, it has been reported with two of the vaccines for the coronavirus, Pfizer-BioNTech and Moderna. (The effect hasn’t been seen with the Johnson & Johnson vaccine.)

Symptoms of either myocarditis or pericarditis can include chest pain, shortness of breath, or an abnormal heartbeat (racing, pounding, or fluttering).

The incidence

According to the Centers for Disease Control and Prevention (CDC), more than 300 million doses of the mRNA vaccines—Pfizer-BioNTech and Moderna—have been administered in the U.S. Of those, there have been 323 cases of myocarditis, pericarditis, or both, all in individuals under the age of 30.

Nearly 80 percent of those have recovered from the symptoms. Nine patients are still hospitalized, with two remaining in intensive care. No deaths have been reported from the condition.

It usually appears within days following the injection of one of the mRNA vaccines, and occurs more often following the second dose. Reported cases have occurred predominantly in male adolescents and adults 16 years of age and older, according to the CDC.

Jeremy Asnes, chief of pediatric cardiology at Yale Medicine and co-director of the Yale New Haven Children’s Hospital Heart Center, says the incidence is incredibly rare. He adds most patients who report symptoms recover quickly.

“I think that the most important message at this point is that we are still recommending eligible people older than 12 follow the vaccine recommendations from the CDC,” he said.

“While we are taking these reports of myocarditis very seriously, we—along with the CDC—continue to feel that the benefits of being vaccinated against COVID-19 far outweigh the very small risk of getting myocarditis related to the vaccine itself.”

Comparison with COVID-19

A study conducted with U.S. military medical centers released by the Mayo Clinic in late June found that the greater risk for heart damage and death continues to be infection with the SARS-CoV-2 coronavirus versus the vaccines. Up to 60 percent of those who become seriously ill with COVID-19 experience some type of injury to their hearts. And nearly one percent of athletes who were previously deemed fit reveal myocarditis on their MRIs after even mild cases of the virus.

“Hypersensitivity myocarditis following vaccination is rare, with the exception of smallpox vaccine,” said Leslie Cooper, chair of the Department of Cardiology at the Mayo Clinic in Florida. “The risk of myocarditis after receiving mRNA vaccine is far less than the risk of myocarditis following actual COVID-19 infection.” Cooper is the senior author of the study.

To illustrate his point, the CDC calculates that for males between the ages of 18 and 29, 60 cases of myocarditis would occur for every million doses of the vaccine. Those vaccines, however, would also prevent 12,000 infections, 530 hospitalizations, and three deaths.

In comparison with the 323 non-fatal cases of myocarditis following the injection, the CDC reports that adolescents and young adults now constitute 33 percent of all new COVID-19 cases. Since the beginning of the pandemic, 7.7 million people ages 12 to 29 have been infected. And 2,767 of those died.

Other considerations

It’s important to remember the other effects that can occur from infection with the COVID-19 virus:

• About 25 percent of those who contract it report lingering symptoms. These include chest pain, shortness of breath, muscle pain, and fatigue. Oddly, these so-called long-haul symptoms tend to occur just as much, if not more often, in those who had only mild or no symptoms of COVID-19.
• The highly contagious and more dangerous delta variant is spreading rapidly in this country, especially among younger people. They tend to be more socially active and are less likely to be vaccinated.

So far, all reported cases of myocarditis, pericarditis, or the extremely rare (fewer than 10) cases of a dangerous blood clotting disorder reported with the Johnson & Johnson vaccine seem to far outweigh the advantages of getting the vaccine.

“People of all ages should choose to get a COVID-19 vaccine because the risks are extremely low compared to the benefits,” said Mayo’s Cooper. “Additionally, the growing body of research shows that vaccine-associated myocarditis resolves quickly in almost all cases.”