*This article was updated on April 16, 2024

Myocarditis and pericarditis after COVID-19 vaccination are rare. Myocarditis is inflammation of the heart muscle, and pericarditis is inflammation of the outer lining of the heart. In both cases, the body’s immune system causes inflammation in response to an infection or some other trigger.

Symptoms of myocarditis and pericarditis:

• Chest pain
• Shortness of breath
• Feelings of having a fast beating, fluttering, or pounding heart

Most patients with myocarditis or pericarditis after COVID-19 vaccination responded well to medicine and rest and felt better quickly.

There are many conspiracy theories circulating online stating that millions of people around the world have suffered from myocarditis or pericarditis after receiving a COVID-19 vaccine. Some theories are claiming that deaths have risen substantially due to these conditions. These theories are untrue. In fact people are much more likely to suffer from myocarditis or pericarditis when they contract Covid-19.

In a report by the UK based Medicines and Healthcare products Regulatory Agency (as of November 23, 2022), “for every million doses given of the monovalent Pfizer/BioNTech vaccine, there have been 10 reports of myocarditis and 6 reports of pericarditis. There have been 14 reports of myocarditis and 8 reports of pericarditis for every million doses given of the monovalent Moderna vaccine over the same period. Similar studies around the world have come to similar conclusions.” 

Men aged 18-29 years old, as well as children in their early teens, seem to be the most likely to develop myocarditis after the second dose of vaccination, but again, the cases are very rare, the symptoms are generally mild and most patients recover within a week.

Similar studies in the US have produced the same findings. According to the CDC, as of March 2, 2023 there have been 376 confirmed cases of myocarditis in children ages 12 to 15 after more than 25 million vaccine doses were administered. In teens ages 16 and 17, there have been 316 confirmed cases after more than 14 million vaccine doses were administered. There were no reported deaths.

It should be noted that these reports were based upon the use of the original Pfizer-BioNTech or Moderna vaccines. Those vaccines, however, are no longer in use in the U.S. after the Food and Drug Administration switched to the updated bivalent formula and moved away from a two-dose primary series. A CDC study published in January that looked at children ages 5 to 11 found no cases of myocarditis following a booster dose of the bivalent vaccine.

*Here at Tayo we aim to offer the latest and best advice regarding Covid-19 and other common respiratory illnesses. The guidelines and suggestions listed here are based upon the recommendations of the CDC and other health care professionals. However, this advice may not suit each individual circumstance and is just meant as general guidelines. We encourage you to consult with your healthcare provider to get the answers that best suit you and your family’s individual needs.