Growing Number of Recurrent, Relapsing Cases of Myocarditis Reported After COVID-19 Vaccination

A healthcare worker reaches for COVID-19 vaccines at a vaccination site in Los Angeles on Feb. 16, 2021. Apu Gomes/AFP via Getty Images

A growing number of cases of recurrent and/or relapsing cases of myocarditis after COVID-19 vaccination are being reported by doctors in medical journals.

One of the newest papers, in the August edition of Vaccine: X, describes two 16-year-old boys who experienced myocarditis after their second doses of Pfizer’s vaccine.

The patients showed recovery and were discharged from the Bambino Gesù Children’s Hospital in Rome.

But they were both readmitted months later, in what researchers described as relapsed cases.

One of the patients reappeared nine months after his initial diagnosis and a cardiac MRI showed abnormalities. Doctors prescribed intravenous immunoglobulins and angiotensin-converting enzyme inhibitors, common treatments for myocarditis following COVID-19 vaccination.

He was discharged after 13 days and advised to avoid strenuous exercise for six months.

The other patient was readmitted eight months after the initial episode, and about six months after being infected with COVID-19. Treatment was started and chest pain improved. He was discharged after six days of hospitalization with recommendation to continue treatment.

Both of the patients experienced persistent late gadolinium enhancement, which experts believe signals scarring of the heart.

Dr. Donato Amodio and the other researchers said that viruses could serve as a trigger for the patients, whose immune systems may have been impacted by the COVID-19 vaccine, which utilizes mRNA.

“Given the short follow-up time and the recent history of the disease, it is still not known whether patients with a prior history of myocarditis after mRNA based COVID-19 vaccine are at increased risk of recurrent myocarditis. Moreover, it would be important to perform genetic evaluation to clarify the presence of mutations in genes associated with cardiomyopathy. Such evaluations are still ongoing in our patients,” Dr. Amodio and colleagues wrote.

Remaining Unknowns

The researchers said the mechanism to post-vaccination myocarditis remains unknown. If the mechanism involves autoimmunity, “remissions and relapses might be expected (like in other autoimmune diseases),” Dr. Eyal Shahar told The Epoch Times in an email.

Autoimmunity is when a person’s immune system attacks itself.

Dr. Shahar, who was not involved in the research and is professor emeritus at the University of Arizona’s Epidemiology and Biostatistics Department, said that autoimmunity “is a plausible mechanism” for the cases.

Dr. Amodio did not respond to a request for comment.

Dr. Sanjay Verma, a cardiologist in California who was also not involved in the study, said that patients with post-vaccination myocarditis need to be monitored regardless of a relapse.

“The risk of sudden cardiac death with excessive or competition-level aerobic activity continues for six months. ... The risk continues for six months even if the heart function were normal. If at the time of initial diagnosis of myocarditis, the heart function were decreased, then the risk of sudden cardiac death with aerobic activity can continue for years,” Dr. Verma told The Epoch Times. “If they have a relapsing episode, as the two cases in that article ... they most definitely need long-term surveillance with a cardiologist.”

That would include follow-up visits to assess symptoms and possible repeat imaging to detect problems like late gadolinium enhancement, which, with classic myocarditis, has been linked to worse outcomes.

Dr. Andrew Bostom, a retired professor of medicine in Rhode Island, reviewed the paper and said the relapses occurred so much later that it’s possible they could have been triggered by another cause. He lamented that the researchers did not test for circulating spike protein.

“That would have been really frightening if there was still evidence that they were producing spike protein, but I don’t think there was evidence for that,” Dr. Bostom told The Epoch Times.

Other Cases

In late 2022, South Korean researchers reported the case of a 17-year-old girl with myocarditis after Pfizer vaccination who was discharged after showing clinical improvement. The next day, she became unconscious while sitting in a restaurant, prompting readmittance.

The girl was discharged again about a month later but hospitalized a third time within nine days for colon inflammation. She was eventually discharged a third time.

In October 2022, Canadian researchers reported that a 25-year-old man with post-vaccination heart inflammation was discharged but readmitted after experiencing recurrent symptoms. Doctors referred to the case as a relapse. They eventually diagnosed the man with chronic myocarditis, among other conditions.

U.S. researchers in May 2022 described the case of a 74-year-old man who was hospitalized with post-vaccination pericarditis, or inflammation of tissue outside the heart. He was discharged, admitted again a week later, and later discharged again with resolution of symptoms.

Israeli doctors in 2021 outlined a man in his early 50s who was admitted with chest pain about a week after receiving a COVID-19 vaccine. The man was discharged but had three subsequent readmissions due to “flare ups of pericarditis during steroid tapering.”

Recurrent Cases

Additional papers have described patients who experienced myocarditis or pericarditis in the past, after a viral infection or vaccination, and saw it recur with a dose of a COVID-19 vaccine.

A 45-year-old man in the United States, for instance, suffered chest pain after COVID-19 infection, again after a first dose of Moderna’s shot, and again after a second vaccine dose. The condition resolved, doctors reported.

A 23-year-old Japanese man suffered viral myopericarditis three years before receiving Moderna’s shot. He was diagnosed with post-vaccination myocarditis. He was eventually discharged and had no lingering symptoms.

Two young people in Australia suffered myopericarditis after second doses of Pfizer’s vaccine. Their symptoms resolved and each received a booster dose of Novavax’s COVID-19 vaccine. Both suffered a recurrence of the heart inflammation afterward.

Other researchers have analyzed sets of patients and found recurrent cases.

In about one year, the Cardiology Department of the University Hospital of Udine saw 24 patients with pericarditis after COVID-19 vaccination with no infection. Five experienced a recurrence of pericarditis.

Among 179 U.S. military members who suffered myocarditis after smallpox vaccination, 11 experienced cardiac symptoms such as chest pain. Four met the criteria for recurrent vaccine-associated myocarditis.

“More research is warranted on factors that may predispose patients to vaccine-associated cardiac injury and which vaccine platforms or schedules may reduce the risk of recurrence among patients who have experienced these events,” researchers said.

Dr. Verma said patients should keep in mind that mixing doses between manufacturers can increase the risk of myocarditis, and that symptoms aren’t always cardiac-involved. He’s seen patients with general symptoms like nausea and fatigue.

Patient Avoided Vaccine

Most researchers reporting such post-vaccination myocarditis cases recommend patients not receive any more doses of the COVID-19 vaccines. But some advise additional shots.

Ben Cutler, a 29-year-old American, suffered myocarditis after a Moderna booster in late 2021. He learned more about the condition, including how it can be caused by other vaccines.

Mr. Cutler consulted his cardiologist to see whether he should avoid any of those vaccines.

“I ask her, ‘Should I be cautious about other vaccines [over] myocarditis?’ She says, completely straight-faced, ‘Next time, just get the Pfizer vaccine,’” Mr. Cutler told The Epoch Times. “It was crazy. I was like, ‘I’m not doing that.’”

By now, with extremely rare exceptions, people who suffered post-vaccination myocarditis should not receive additional shots, Dr. Bostom said.

The U.S. Centers for Disease Control and Prevention (CDC) says that people with the condition should generally avoid more shots but that more doses may be administered once symptoms resolve. The CDC has directly advised some patients to get additional doses, even when the agency could not rule out vaccination as a cause of their adverse event.