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.
Health officials have said that the risks of developing heart inflammation are outweighed by the vaccine’s benefits.
“The risk of myocarditis and pericarditis appears to be very low given the number of vaccine doses that have been administered,” Janet Woodcock, the acting FDA commissioner, said in a statement last week. “The benefits of COVID-19 vaccination continue to outweigh the risks, given the risk of COVID-19 diseases and related, potentially severe, complications.”
The warning issued by the FDA says that there may be increased risks “particularly following the second dose and with [the] onset of symptoms within a few days after vaccination.”
“Additionally, the Fact Sheets for Recipients and Caregivers for these vaccines note that vaccine recipients should seek medical attention right away if they have chest pain, shortness of breath, or feelings of having a fast-beating, fluttering, or pounding heart after vaccination,” the agency said. “The FDA and CDC are monitoring the reports, collecting more information, and will follow-up to assess longer-term outcomes over several months.”
Representatives for Pfizer and Moderna didn’t respond to requests for comment by press time.