FDA adds heart inflammation warning to Moderna, Pfizer vaccines

The US Food and Drug Administration (FDA) has added a warning about the risk of heart inflammation to fact sheets for Moderna and Pfizer-BioNTech COVID-19 vaccines.

The warning on Friday noted that reports of adverse events following vaccination – particularly after the second dose – suggest increased risks of myocarditis, or inflammation of the heart muscle, and pericarditis, or inflammation of the tissue surrounding the heart.

The warning update follows an extensive review of information and discussion by the US Centers for Disease Control and Prevention (CDC’s) Advisory Committee on Immunization Practices meeting on Wednesday, the FDA said.

At end of the second week of June, more than 1,200 cases of myocarditis or pericarditis have been reported to the US Vaccine Adverse Event Reporting System.

The cases reportedly appear to be notably higher in males and in the week after the second vaccine dose.

There has been no comment from Pfizer and Moderna yet.