Some children, particularly boys, may develop myocarditis after receiving an mRNA COVID-19 vaccine, according to a study published August 10 in JAMA Cardiology.
A team led by Dr. Audrey Dionne of Boston Children's Hospital found that, of a small patient sample, 93% of children developed myocarditis after vaccination. These findings suggest that children should be tracked for heart complications.
Dionne's team investigated 15 case studies of children younger than 19 years of age who were hospitalized with myocarditis within 30 days after receiving an mRNA COVID-19 vaccine. The children were admitted between May and July of this year; 14 (93%) were boys.
Symptoms appeared between one and six days after the vaccine (chest pain, fever, myalgia, and headache). All patients had elevated troponin levels on hospital admission. All underwent a cardiac evaluation that included an echocardiogram, an electrocardiogram, and cardiac MRI.
Cardiac MRI findings pointed to myocarditis in 13 of the 15 patients (87%); boys were more commonly affected, and after the second vaccine dose. None of the children were transferred to the intensive care unit, and median length of stay in the hospital was two days, the team found. At follow-up one to 13 days after discharge from the hospital, 73% had recovered.
"The long-term risks associated with postvaccination myocarditis remain unknown," the team concluded. "Larger studies with longer follow-up are needed to inform recommendations for COVID-19 vaccination in this population."
