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 myocarditis or pericarditis in young people who received Covid-19 vaccine from Pfizer or Moderna, according to a series of presentations released Wednesday for a meeting of the CDC’s Advisory Committee on Immunization Practices.
Myocarditis is the inflammation of the heart muscle while pericarditis is the inflammation of the membrane that surrounds the heart.
“The clinical picture of myocarditis cases after vaccination was different and most often appeared within a week after the second dose, with chest pain being the most common manifestation,” said one of the presentations. CDC officials are collecting more data to fully understand the potential risks, how to deal with it, and if there are any long-term problems.
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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.
“This is still a rare occurrence,” said Dr. Tom Shimabukuro at the meeting. For both vaccines combined, there were 12.6 million cases of heart inflammation per million doses. Cases were more common among Moderna vaccine recipients at 19.8 cases per million than 8 cases per million at Pfizer, he 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 like chest pain and shortness of breath usually develop within a week of receiving the vaccination, with most developing within four days, the agency said.
This is a developing story. Please check again for updates.