Maine CDC Health Advisory

May 26, 2021

Cases of Myocarditis/Pericarditis Following COVID-19 Vaccination

The U.S. Centers for Disease Control and Prevention is aware of reports of myocarditis and pericarditis after receipt of a COVID-19 vaccine. The reports appear to be rare, given the number of vaccine doses administered to date. U.S. CDC is investigating whether there is any causal association or an increase of such events relative to the background rates.

Myocarditis is an inflammation of the heart muscle and pericarditis is the inflammation of the lining outside the heart. In both cases, the body's immune system causes an inflammation in response to an infection or some other trigger. While myocarditis can be serious, it is frequently mild and self-limited. Symptoms can include abnormal heart rhythms, shortness of breath, or chest pain. Myocarditis is often caused by a viral infection, but it can result from a reaction to a drug or as part of a more general inflammatory condition. Myocarditis itself not a notifiable condition in Maine.

Maine CDC has received reports of cases of myocarditis occurring in Maine residents after receipt of an mRNA COVID-19 vaccine. Since there is usually an increase in myocarditis at this time of year, it is not known if these cases are associated with receipt of the vaccine. Vaccination for COVID-19 remains strongly recommended. U.S. CDC will continue to evaluate reports of myocarditis/pericarditis occurring after COVID-19 vaccination and will share more information as it becomes available.

Advisory (PDF)