The US Food and Drug Administration will now require Covid-19 vaccines from Pfizer/BioNTech and Moderna to use expanded warning labels with more information about the risk of a rare heart condition after vaccination.

The FDA is requiring COVID vaccine makers Pfizer and Moderna to update their warnings about the possible risk of myocarditis and pericarditis.

According to the CDC, cases of myocarditis and pericarditis are rare with the vaccines and in most cases resolve within a few days of dosing. None of the companies involved have commented on the change in the warning text.