Rare cardiac effect of vaccine usually improves quickly - report

The few pediatric recipients of COVID-19 vaccines who develop a heart muscle inflammation known as myocarditis are likely to have mild symptoms that improve quickly, according to a report published on Monday in the American Heart Association (AHA) journal Circulation.

The rare side effect has been most often reported among adolescent and young adult males.

Researchers reviewed data from 26 children's hospitals across the United States and Canada, focusing on 49 patients ages 12 to 20 who were hospitalized for "confirmed" myocarditis within a month of receiving the vaccine, and 91 with "probable" myocarditis.

Most (91%) were male, 66% were white, and the average age was about 16. While 19% required intensive care, no one died.

Half of the patients were sent home within two days.

While COVID-19-vaccine-related myocarditis is usually mild and usually resolves quickly, the condition is nevertheless "a cause of great concern," and it is not clear yet how patients do over the long term, the researchers said.

Still, they concluded, "its risk must be balanced against critical illness and cardiovascular involvement" associated with COVID-19.

In a press statement, AHA President Dr. Donald Lloyd-Jones, who was not involved in the study, said that data has shown that the benefits of COVID-19 vaccination "far exceed the very rare risks of adverse events, including myocarditis." -- Reuters