A heart inflammation condition in adolescents and young adults who received Covid-19 vaccines appears to be very rare and it remains unclear if the issue is actually related to the shots, the Food and Drug Administration's top vaccine regulator, Dr. Peter Marks, said Thursday.
The Centers for Disease Control and Prevention's vaccine safety group said last week it was looking into a condition called myocarditis, which is an inflammation of the heart muscle, in a "relatively few" people who received Covid vaccinations.
Myocarditis can affect one's heart muscle and heart electrical system, "reducing its ability to pump and causing rapid or abnormal heart rhythms," according to the Mayo Clinic.
The cases were predominantly in adolescents and young adults and usually occurred within four days after getting the shot, according to the CDC. The condition was seen more often in men and most cases appear to be mild, the agency said, though officials are following up with the patients.
"We still don't know whether this is truly related to the vaccine," Marks, director of the FDA's Center for Biologics Evaluation and Research, said during a virtual Q&A event with the COVID-19 Vaccine Education and Equity Project.
The CDC is coordinating its investigation with the FDA, which recently authorized the Pfizer-BioNTech vaccine for adolescents ages 12 to 15. The vaccine has been available for Americans 16 and up since December. Vaccines from Moderna and Johnson & Johnson are available to those 18 and older.
Health experts say finding rare side effects once a vaccine or drug is administered to the general population is common and if myocarditis turns out to be related to the Covid vaccine, the risk is negligible when compared with the risks of being infected with Covid-19.
Marks, who has been at the FDA for nearly a decade, added Thursday that the "handful" of cases reported have been "very mild, lasting a day or two" and usually happened after a second dose.
"My kids are a little older, but I wouldn't hesitate to vaccinate my children, just because this is a pretty rare finding and we really don't know yet if it's truly related" to the vaccines, he said.