Risk for Myocarditis in Young Who Get Moderna Shots May Be Greater Than Thought

The Moderna COVID-19 vaccine may be linked to a higher risk for myocarditis in younger adults than believed, emerging reports show.

Federal health officials are investigating the new data, according to two people familiar with the review who emphasized the side effect is still rare, The Washington Post reported. Vaccination is still by far the healthier option, since the U.S. Centers for Disease Control and Prevention vaccine advisers have already said that getting COVID-19 puts someone at much greater risk for heart inflammation and other serious medical problems than getting the vaccine does.

But officials from the U.S. Food and Drug Administration and the CDC are focusing on data from Canada that suggest the Moderna vaccine may carry a higher risk for this rare condition for young people compared with the Pfizer vaccine, particularly for males younger than 30 years. They are also analyzing U.S. data to determine whether the same is happening in the United States, The Postreported. The Canadian data suggest there might be a 2.5 times higher incidence of myocarditis in those who get the Moderna shot compared with the Pfizer vaccine.

One of the people familiar with the investigation emphasized that the agencies must do more research before deciding whether to issue any new or revised warning for the Moderna vaccine. In June, the FDA added a warning label for the Pfizer and Moderna shots about an increased risk for myocarditis.

Moderna did not respond to a request for comment.