CDC Reports Rare Heart Inflammation Associated With Pfizer, Moderna Vaccines

A Centers for Disease Control and Prevention (CDC) expert panel yesterday concluded that there is likely a link between heart inflammation and inoculations with the Pfizer/BioNTech and Moderna COVID-19 vaccines but emphasized that the benefits of the shots greatly outweigh the risks.

The CDC’s surveillance found 1,226 reported cases, including 636 confirmed cases, of messenger RNA-associated myocarditis or pericarditis from its vaccine adverse events tracking systems, mainly in adolescents and males under 30 years of age, according to data presented yesterday at a meeting of the CDC’s Advisory Committee on Immunization Practices. The adverse events were reported more frequently with the Moderna vaccine than the Pfizer one.

More than 308 million mRNA vaccine doses have been administered in the U.S., but most of those have gone to older adults. As of June 11, roughly 8 million were administered to the 12-to-29 age group.  The combined rate of inflammation cases for both vaccines combined was 12.6 cases per million doses.

Symptoms generally occurred a week after vaccination with a second dose of either the Pfizer or Moderna vaccines, CDC officials said.

The expert panel cautioned about the lack of long-term data regarding the rare cases of heart inflammation and said it might update its recommendations as it investigates additional reports currently under review.

The CDC is coordination its investigation with the FDA, which authorized the Pfizer/BioNTech vaccine in adolescents 12 years and older last month (DID, May 11) and is currently considering an update of the Moderna vaccine’s Emergency Use Authorization to allow its use in adolescents. — Jason Scott