September 23, 2023

The headquarters of the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.

Tami Chapel | Reuters

A CDC safety group said there was a “likely link” between rare heart inflammation in adolescents and young adults, mostly after they received their second Covid-19 vaccine, citing the latest available data.

There have been more than 1,200 cases of rare heart inflammation in people who received the Covid-19 vaccine from Pfizer or Moderna, according to a slide show released Wednesday ahead of a consultative meeting at the Centers for Disease Control and Prevention.

The CDC’s Advisory Committee on Immunization Practices will hold a meeting to discuss rare but unexpectedly high reports of myocarditis or pericarditis in 16- to 24-year-olds after receiving the mRNA vaccines. Myocarditis is the inflammation of the heart muscle while pericarditis is the inflammation of the membrane that surrounds the heart.

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The agency said 267 cases of myocarditis or pericarditis were reported after receiving one dose of the mRNA vaccines and 827 cases after two doses by June 11. There are 132 additional cases where the number of doses received is unknown, the CDC said.

By June 11, around 300 million shots had been administered, the CDC said.

Men under 30 make up the bulk of cases, the CDC said, and most cases appear to be mild. Of the 295 people who developed the disease and were discharged, 79% made a full recovery, according to the presentation. Nine people were hospitalized, according to the CDC, two of them in intensive care.

The CDC is coordinating its investigation with the Food and Drug Administration, which last month approved the Pfizer BioNTech vaccine for adolescents ages 12-15. Symptoms such as chest pain and shortness of breath typically develop within a few days of receiving the vaccination, the agency said.

This is a developing story. Please check again for updates.