The U.S. Food and Drug Administration added a warning to information sheets for the Pfizer and Moderna Covid-19 vaccines on Friday to indicate a rare risk of heart inflammation.
The fact sheets were revised to include a warning about myocarditis and pericarditis after the second dose and with the onset of symptoms within a few days after receiving the shot.
Myocarditis is the inflammation of the heart muscle and pericarditis is the inflammation of the tissue surrounding the heart. Health officials said the benefits of receiving the vaccine still outweigh any risk.
“The risk of myocarditis and pericarditis appears to be very low given the number of vaccine doses that have been administered,” Janet Woodcock, acting FDA commissioner, said in a statement.