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

Tami Chapel | Reuters

There have been more than 1,200 cases of rare heart inflammation in people who had received the Covid-19 vaccine from Pfizer or Moderna, according to a CDC presentation slide released Wednesday ahead of an advisory meeting.

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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