Some children who experienced heart inflammation after COVID-19 vaccination had scarring on their hearts months later, a new long-term study found.
Researchers followed a group of 40 patients aged 12 to 18 for up to one year after the children were diagnosed with myocarditis, or heart inflammation, following vaccination with one of the messenger RNA vaccines from Pfizer or Moderna. They performed a series of tests, including echocardiograms.
Cardiac MRIs were performed on 39 of the 40 patients. Abnormal results came in for 26 of those who were imaged, including 19 who had late gadolinium enhancement, or signs of scarring.
The patients with abnormal results returned for follow-up cardiac MRIs at least five months after the initial tests and 15, or 58 percent, had residual late gadolinium enhancement (LGE). The one patient without an initial scan also had mild late gadolinium enhancement when scanned during a follow-up visit.
"Persistence of LGE in a significant subset of patients with up to 1 year of follow-up was observed," Dr. Yiu-fai Cheung, with Hong Kong Children's Hospital, and the other researchers wrote.
They said the implications of the persistence remain unclear but that given it's an indicator of subclinical heart dysfunction and scarring, "there exists a potential long-term effect on exercise capacity and cardiac functional reserve during stress."
Dr. Peter McCullough, an American cardiologist and president of the McCullough Foundation, said the new data is consistent with what cardiologists are seeing in clinical practice.
"Serious cases of COVID-19 vaccine-induced myocarditis are not resolved by cardiac MRI at one year of followup in the majority of cases. At some point, we must assume that late gadolinium enhancement represents a scar or permanent damage," Dr. McCullough, who wasn't involved in the research, told The Epoch Times via email.
"COVID-19 vaccines should be pulled from the market immediately until further notice. Large-scale research programs should be commissioned immediately on subclinical and clinical COVID-19 vaccine induced myocarditis with initial aims at risk stratification and mitigation for cardiac arrest."
Dr. Anish Koka, another American cardiologist who wasn't involved in the study, said the persistent LGE signifies a scar that replaced the initially inflamed heart muscle.
He said the level of scarring indicates there likely wouldn't be a long-term impact but that even small levels of scarring could be a foundation for future arrhythmias, with exercise serving as a trigger.
"All these kids (even those without scar) would need exercise stress tests at 6 months to attempt to prognosticate this," Dr. Koka said.
Pfizer and Moderna didn't respond to requests for comment on the study on myocarditis, a known side effect of both of the companies' COVID-19 vaccines.
More EvidenceMyocarditis after COVID-19 vaccination was first detected in early 2021, and an increasing number of studies have undercut claims from officials in the United States that the heart inflammation is mild and resolves without treatment.
The study relied on surveys from health care providers who examined the patients.
Myocarditis can cause deaths, including sudden deaths, and deaths from myocarditis after vaccination have been confirmed in a number of countries, including South Korea, the United States, and Germany.
Vaccine-induced myocarditis primarily affects young people, particularly young males.
Some critics say that all people, or certain people, don't need a vaccine, noting the risks as well as the high percentages of people who have been vaccinated, infected, or both.