Myocarditis Is A 'Rare' Vaccine Side Effect In Kids, But How Rare?

How Often Do Covid Vaccines Cause Heart Problems In Kids?

Female doctor examining preschool patient at home
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As the COVID vaccines have rolled out for our kids, we parents have had some understandable concerns. Even if we feel sure that it’s important to protect our children from becoming infected with COVID-19, and decrease the chances of them spreading the virus to others, we may have some reservations about giving them a vaccine they’ve never gotten before.

One of parents’ biggest concerns is side effects. Although most of the side effects of COVID vaccines seen in teens and young kids have been mild (sore arm and fever, for example), we’ve all heard of a rare but concerning side effect that some kids have had: myocarditis, an inflammation of the heart.

Soon after the COVID-19 vaccine rolled out to teenagers, news began to appear that some teens had experienced myocarditis as a side effect of the vaccine. I remember when this happened, because my teen son had just received his first shot. At first, it was unclear if the instances of myocarditis were caused by the vaccine directly or if it was a matter of correlation rather than causation.

(IMPORTANT NOTE: Any number of things can happen to you after you are vaccinated, but you can only know if these things were caused by the vaccine if all the smart scientists and doctors get together and figure it out.)

Eventually, it became clear that yes, myocarditis can be a side effect of the COVID vaccine, but that this is a very rare side effect, that the cases of myocarditis after vaccination are mild and usually easily resolve. Additionally, COVID-19 itself can cause much worse myocarditis, which is why the CDC decided that the risks of COVID-19 were greater than the risks of vaccination, and why these shots are still being offered to teens (and now kids aged 5-11).

Now, before we get into the nitty gritty here of what this all means, and what “rare” actually means in terms of numbers, can we take a moment to consider the power of transparency and accountability in organizations like the CDC and FDA? All the conspiracy theorists talk about how these agencies are purposefully withholding information from us, and how they are in the pocket of the pharmaceutical companies, and are just looking to poison us all.

But then why would they publish what could be a scary side effect for parents and potential vaccine recipients to hear about? Why would they do this? Because it’s their job to give us all facts, and to make sure that the medications and vaccinations we receive have been scrutinized and that all the known risks are investigated thoroughly.

I dunno, but I find that pretty reassuring. Anyway. Back to those risks…

So, if everyone is saying myocarditis after vaccination is rare, what does that really mean? I know that as a parent, “rare” is all fine and good, but if “rare” happens to my child, it’s not okay.

Well, research from Israel, published last month in Nature, has some concrete answers. Researchers there looked specifically at instances of myocarditis in teen boys and young men, who are most likely to experience this side effect.

Two large studies were conducted, and what the researchers found is that people generally have about a 1 in 50,000 chance of developing myocarditis. In young men aged 16-19, that risk was somewhat higher. 15 out of every 10,000 young men in that group developed myocarditis. Importantly, as the report explains, “The vast majority of these cases were mild and eventually resolved.”

According to The New York Times, data on myocarditis in younger teens (12-15) and younger children is still limited at this time, but doctors actually believe that these instances will be lower than in older teens and young men. Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, tells The New York Times that myocarditis after vaccination is happening less often in younger teens.

In fact, Dr. Offit says that in general, myocarditis affects kids most after they have passed puberty, and that this is in line with what he is seeing. “Myocarditis is usually a post-pubertal phenomenon,” Dr. Offit told the Times.

As such, Dr. Offit says he doesn’t expect to see a large number of children in the age 5-11 year old range being affected by myocarditis after getting vaccinated. (Of note, none of the children in Pfizer’s vaccine trial got myocarditis, though this is a smaller sample size.)

Again, though, probably the most important thing to keep in mind is that when teens do get myocarditis following COVID vaccination, cases are generally mild, and are nothing compared to the risk of getting myocarditis from a COVID-19 infection.

Importantly, no children have died in the U.S. a result of myocarditis from a vaccine, and most recover within a few days. But the same can’t always be said about children who have gotten myocarditis as a result of a COVID-19 infection.

As Dr. Sarah Long, a pediatric infectious disease expert at Drexel University College of Medicine, tells Popular Science, myocarditis as a result of a COVID-19, or any viral infection can be severe.

“It is a typical syndrome that is not good to have,” she explains. “They take a long time to get better. Some of them never get better. There is mortality, and some of them get to heart transplant.”

YIKES.

Look, we are all going to have different thoughts and feelings on vaccinating our children. But all major health organizations recommend that we vaccinate our children, including the CDC and Academy of American Pediatrics. I think we can all rest assured that the data on myocarditis has been thoroughly pored through by the experts, and that the risk of your child getting a serious case of COVID-19 is much higher than them getting the vaccine.

I understand reservations that parents have, but the numbers are very low, and data looks reassuring. Of course, don’t hesitate to contact your pediatrician if you have any questions or concerns. That’s what they are there for.