CDC investigating heart problems in a few young mRNA vaccine recipients

INDIANA – The CDC is investigating whether the COVID-19 vaccine caused myocarditis and pericarditis in young adults and adolescents following the mRNA COVID-19 vaccination (Pfizer-BioNTech and Moderna) in the United States.

Myocarditis is an inflammation of the heart muscle, in a relatively small group of young people. Pericarditis is inflammation of the pericardium, a sac-like structure with two thin layers of tissue that surround the heart to hold it in place and help it work. A small amount of fluid keeps the layers separate so there’s less friction between them as the heart beats.

According to the CDC, a relatively small number of cases have been reported, with the symptoms mostly impacting younger males within four days of their second dose. These reports are rare, given the number of vaccine doses administered.

Cases reported have occurred:

  • predominantly in adolescents and young adults,
  • more often in males than females,
  • more often following dose 2 than dose 1, and
  • typically within 4 days after vaccination.

The symptoms are often mild fatigue, sometimes shortness of breath, sometimes chest pain, but sometimes individuals can have heart failure and arrhythmias.

Patients can usually return to their normal daily activities after their symptoms improve, and they should speak with their doctor about return to exercise or sports.

CDC continues to recommend COVID-19 vaccination for everyone 12 years of age and older, given the greater risk of COVID-19 illness and related, possibly severe complications.