The young adults (more males than females) developed symptoms of myocarditis within four days of receiving the second shot of either the Moderna or Pfizer-BioNTech vaccines—both of which are made with messenger RNA (mRNA).
For now, the CDC is urging healthcare professionals to look out for unusual heart symptoms in young people who have received any of the three COVID-19 vaccines that are approved in the United States. Currently, only the Pfizer-BioNTech COVID vaccine is approved for use in children aged 12 and older in the U.S.
Investigating Cases
In April, a few cases of myocarditis were reported in people in Israel who had recently received a COVID vaccine. In early May, the CDC alerted physicians in the U.S. that it was receiving reports of myocarditis in adults who had recently been vaccinated.
The reports were evaluated by the Vaccine Safety Technical (VaST) Work Group. The VaST’s report stated that “within CDC safety monitoring systems, rates of myocarditis reports in the window following COVID-19 vaccination have not differed from expected baseline rates.”
Leslie Cooper, MD, the co-founder and medical director of the Myocarditis Foundation and chair of the Department of Cardiovascular Medicine at the Mayo Clinic in Jacksonville, Florida, tells Verywell that most of the reported cases of myocarditis in teens who had recently been vaccinated were mild. The patients were treated with anti-inflammatory drugs such as ibuprofen and a drug called colchicine, and most have recovered without any long-term health problems.
Reporting and Tracking Cases
Cooper says that the incidence of myocarditis in the general population is estimated to be around 10 cases per 100,000 persons, but it can be up to 20 per 100,000 people in some locations. He does not have data on the number of cases of myocarditis in teenagers yet.
In the U.S., an important tool for finding out about cases of adverse events after vaccination is the Vaccine Adverse Event Reporting System (VAERS), which is run by the Department of Health and Human Services.
Cooper says that the number of cases of myocarditis in people of all ages being reported to VAERS is rising because more people are becoming aware of it. He estimates that overall, there could be around one case of myocarditis in every 100,000 vaccinations in all age groups—which is not that different from the baseline rate. However, Cooper adds that the rate in males between the ages of 18 and 25 appears to be a bit higher than the baseline rate.
Studies are underway on the potential risk of myocarditis for young people who have been vaccinated. Cooper cites one report of cases in the U.S. military, which has not been yet been published, which showed a rate of 14 cases of myocarditis in every 600,000 people vaccinated.
For now, Cooper says that experts “don’t believe the risk of myocarditis is a contraindication to vaccination.”
Experts Want You To Get Vaccinated
The cases of myocarditis reported in people who recently got their COVID shot might be a situation in which two things are happening at the same time, but are not connected. Researchers refer to this as correlation versus causation.
Even if there is a connection between myocarditis and COVID-19 vaccines, Cooper stresses that getting vaccinated is still the wise thing to do.
“Yes, there is a small rate of cardiac injury, presumed to be myocarditis, in young people who received the mRNA vaccines, both Pfizer and Moderna,” says Cooper. “This adverse event is not nearly as significant as the morbidity from the virus itself.”
A COVID-19 infection can cause cardiovascular problems, including myocarditis, in people who were previously healthy. Additionally, lingering cardiovascular symptoms, like heart palpitations and heart arrhythmias, can occur after a COVID infection.
As vaccination opens up for younger people, including teens, experts do not want concerns about myocarditis to deter people from getting vaccinated.
In an email to Verywell, the American Academy of Pediatrics (AAP) stated that the “potentially rare side effect of myocarditis pales in comparison to the potential risks of COVID-19 infection.”
According to the AAP, nearly four million children in the U.S. have tested positive for the disease since the start of the pandemic. As such, the AAP recommends that people aged 12 and older be vaccinated against COVID-19.
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.
