What a study on heart inflammation in COVID-19 vaccinated kids reveals

While COVID-19 vaccines have reportedly caused rare cases of myocarditis — or inflammation of the heart — in youth, a new study involving Utah researchers found that in most cases the condition is mild and resolves itself in a short period of time.

Dr. Dongngan Truong, pediatric cardiologist with University of Utah Health and Primary Children's Hospital, said that as the vaccine rolled out worldwide, some doctors reported patients with myocarditis, which occurred initially in Israel and then in the U.S. As the vaccine became available to younger populations, Truong said she and her colleagues started to see cases in children "here and there."

"And we started to wonder how did these kids present (symptoms). We felt that it was important so that people in the community know what to look out for and to provide information on how these kids do in the short term," Truong said.

In 139 vaccine-eligible children and adults under age 21 who experienced myocarditis, "the major findings in the study were that most patients were male, and about 90%. ... And we were typically seeing this myocarditis after the second dose of vaccine," according to the doctor.

The symptoms typically began within a week of the second dose, and most commonly included chest pain. Sometimes, patients experienced shortness of breath or fever. According to echocardiograms performed on the patients, about 19% had decreased heart function which for most normalized quickly, Truong said.

The patients' lengths of stay in hospitals were brief overall, Truong said, and they required minimal treatment with medication.

"We were pleased to see that kids recovered quickly in that respect," she added.

The doctor said it will be important to follow the patients long term to see their outcomes.

Myocarditis is not unique to the COVID-19 vaccine, Truong said — the smallpox vaccine received attention in the past for causing it as well.

While myocarditis does sound like a scary term, Truong said, it is a "catchall" word to describe heart inflammation. For years, doctors have seen myocarditis cases stemming from different causes, including viruses. There isn't yet a way to determine if one person is more at risk for experiencing myocarditis.

Truong emphasized that the myocarditis cases in children after receiving the COVID-19 vaccine have been extremely rare. In risk analyses by the Centers for Disease Control and Prevention, the balance "has always been in favor" of vaccination, even in those ages 12 to 17 who had the highest rates of myocarditis among children.

Doctors at Intermountain Primary Children’s Hospital in Salt Lake City review scans looking for multisystem inflammatory syndrome in children, or MIS-C. | Intermountain Primary Children’s Hospital

New Utah data

Utah health officials reported 1,423 new COVID-19 cases and 16 deaths on Wednesday.

School-age children accounted for 240 of the new cases — 126 cases were ages 5-10, 46 cases were 11-13, and 68 were 14-17.

The rolling, seven-day average for new cases is 1,416 per day, and the average positive rate of those tested is 15.7%, the Utah Department of Health said.

Hospital use appears to be plateauing in the state, as current coronavirus hospitalizations have remained consistent for the past several days, according to data from the state health department. On Wednesday, 521 people were hospitalized with the coronavirus across Utah. Referral intensive care units that can treat the most serious patients were 97.5% full, while overall ICU use stood at 93.1%.

Health care workers administered 19,764 vaccine doses since the previous day's report, bringing total doses given in Utah to 4,273,903.

Of the cases confirmed Wednesday, 467 were "breakthrough," meaning they had been fully vaccinated more than two weeks earlier. Now breakthrough cases represent 52,207, or about 8.6%, of the state's 607,954 total cases since the pandemic began. No additional breakthrough deaths were confirmed Wednesday, leaving that number at 313, or about 8.6% of Utah's deaths caused by COVID-19.

The deaths reported Wednesday included:

  • Two Salt Lake County men, 25-44, hospitalized.
  • Two Salt Lake County men, 45-64, hospitalized.
  • A Davis County man, 45-64, hospitalized.
  • A Salt Lake County woman, 18-24, hospitalized.
  • A Carbon County man, 45-64, hospitalized.
  • A Weber County woman, 65-84, hospitalized.
  • A Box Elder County man, 65-84, hospitalized.
  • A Salt Lake County woman, older than 85, not hospitalized.
  • A Utah County woman, 45-64, hospitalized.
  • A Washington County woman, 65-84, hospitalized.
  • An Iron County man, 25-44, hospitalized.
  • A Duchesne County woman, 65-84, hospitalized.
  • A Duchesne County man, 65-84, hospitalized.
  • A Cache County man, 65-84, hospitalized.