(NEXSTAR) – Kids, teens, and young adults weighing whether to get vaccinated against coronavirus may have heard of a new side-effect to be concerned about: myocarditis.

Myocarditis is inflammation of the heart and a very rare side-effect of the COVID-19 vaccine. It appears most commonly in adolescents and young adults, especially boys, according to the Centers for Disease Control. Because myocarditis seems to happen after the second dose of the vaccine, other countries like Hong Kong, Norway, Denmark, and Sweden have started recommending healthy teens only get one dose, the New York Times reported.

“There’s a wrong assumption that COVID does not give you myocarditis. Myocarditis is far more significant with COVID than with the COVID vaccine.”

Dr. Anjan Batra, professor of clinical pediatrics at University of California, Irvine.

Should we consider doing the same in the United States? Right now, the experts say no for two key reasons.

First off, the other countries that are suggesting just one dose for young people have far lower rates of COVID-19 cases.

“Where we are, we are the leaders in COVID, unfortunately,” said Dr. Anjan Batra, professor of clinical pediatrics at the University of California, Irvine. The U.S. ranks No. 1 in the world for most cases and deaths. “If you had very few cases, you could come up with some sort of a compromise. … I don’t know if the [one-dose] compromise is the answer here.”

In countries like Hong Kong, the risk of getting COVID is much lower than in the U.S. If COVID is rare, you might feel more empowered to make decisions based on rare side effects. But if COVID is a real and present threat, you might not have that luxury.

Second – and even more important, Batra said – if parents are really worried about heart inflammation, they should worry about COVID-19.

“There’s a wrong assumption that COVID does not give you myocarditis. Myocarditis is far more significant with COVID than with the COVID vaccine.”

Myocarditis can lead to rhythm issues with the heart (beating too fast or too slow) or it could squeeze the blood vessels that feed the heart. Generally, myocarditis appears as the result of a viral infection, Batra explained. But research has found it’s exceptionally rare as a result of the COVID vaccine.

“If you look at the numbers, the patients who get myocarditis from the vaccine are about 12 in a million,” said Batra. “The other thing to keep in mind is those that do get myocarditis or inflammation from the vaccine, for pretty much all of them, this is a temporary phenomenon that gets better.”

Batra said he’s seeing something more concerning than myocarditis in his pediatric patients: MISC, or multisystem inflammatory syndrome in children.

“We are seeing a lot of patients with that in our hospital,” he said. “The effects of this, which include myocarditis but are not limited to myocarditis, involves blood vessels that lead to the heart are significantly dilated. That is much more dangerous. That has a much higher chance of mortality from this condition and long-term consequences for the heart.”

Batra said questions about COVID-19 and the vaccine have become a huge part of his practice. “It has even superseded cardiology now. Every parent and every child has this question.”

In medicine and in life, Batra said, nothing is 100% certain. Everything is a risk assessment, a cost-benefit analysis. He encourages his patients to read medical journals and vetted studies to help them make their decisions. His two kids got vaccinated as soon as they were eligible, he said.

To Batra, the risk of being unvaccinated or partially vaccinated against COVID poses higher risks to kids’ and teens’ heart health than the vaccine.

Seattle health officer Dr. Jeffrey Duchin agreed, telling the New York Times, “All the data that we have so far suggests the disease itself is significantly worse than the vaccine side effects.”

The CDC advises everyone 12 and older to get both doses: “The known risks of COVID-19 illness and its related, possibly severe complications, such as long-term health problems, hospitalization, and even death, far outweigh the potential risks of having a rare adverse reaction to vaccination, including the possible risk of myocarditis or pericarditis.”