The U.S. Food and Drug Administration (FDA) has added a warning about the risk of developing heart inflammation to information about the Moderna and Pfizer COVID-19 vaccines.
The FDA announced earlier this month that it would add the warning after the Centers for Disease Control and Prevention (CDC) reported that more cases of heart inflammation—either myocarditis or pericarditis—had been found in young adults and children after they received the vaccines, which use mRNA technology.