Several studies have shown that in rare cases, adolescent and young adult males have developed myocarditis after receiving mRNA Covid-19 vaccine – and now new research published in the journal Science Immunology sheds light on potential causes.
Scientists at Yale University School of Medicine in New Haven, Connecticut, conducted tests on a group of 23 patients with myocarditis (inflammation of the heart muscle) and/or pericarditis (swelling and irritation of the membrane surrounding the heart) associated with the vaccine. .
The scientists discovered that the disease was not caused by antibodies produced by the vaccine, but by the body’s natural immune response to the vaccine.
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“THE [researchers] looked at a number of different mechanisms in terms of immune responses and were able to rule out adaptive immune responses – so no specific antibody-mediated responses targeting the virus or the heart itself,” said Dr. Donald M. Lloyd -Jones, former president of the American Heart Association and director of the Department of Preventive Medicine at Northwestern University Feinberg School of Medicine in Chicago.
in rare cases, adolescent and young adult males have developed myocarditis after receiving the COVID-19 mRNA vaccine – and now new research is shedding light on potential causes. (Stock)
After reviewing the study results, Lloyd-Jones told Fox News Digital that the researchers identified a “nonspecific immune response in which the heart is an innocent bystander, with nonspecific inflammation and some fibrosis formation. (scar tissue)”.
Patients were healthy prior to vaccination
The 23 patients included in the study were between 13 and 21 years old, with an average age of 16 years. Men made up 87% of the group, according to the journal Science Immunology.
All of the patients were “generally healthy” before receiving the vaccine, according to a discussion of the study results in the journal. Most of them began to experience symptoms within four days of receiving the second dose of the Pfizer-BioNTech COVID-19 vaccine.
“It doesn’t seem to have any long-term consequences for the heart.”
The researchers looked at several possible causes of myocarditis, including a vaccine-triggered antibody immune response, an allergic reaction to the vaccine, and antibodies that specifically target the heart, the journal Science noted.
After ruling out these possibilities, they concluded that the vaccine triggered an exaggerated immune response in which the heart was inadvertently touched.
Symptoms of myocarditis
In the Yale study, participants experienced many symptoms commonly associated with myocarditis, including chest pain, heart palpitations, shortness of breath, fever, fatigue, headache, nausea, pain muscles and excessive sweating.
Most cases of vaccine-related myocarditis resolve quickly with treatment.
Common treatments include nonsteroidal anti-inflammatory drugs (ibuprofen) and blood pressure medicationaccording to the Beaumont Health website.

The scientists carried out tests on 23 patients with myocarditis (inflammation of the heart muscle) and/or pericarditis (swelling and irritation of the membrane surrounding the heart) associated with the vaccine. (Stock)
In rare cases, patients may need IV drugs or machines to help the heart.
“Even if this inflammation does occur, it appears to be fairly self-limiting and does not appear to have long-term consequences for the heart,” Lloyd-Jones said.
Anyone with symptoms should see a doctor for tests and medication as needed, experts recommend.
Risk remains low, experts say
According to the Centers for Disease Control and Prevention (CDC), the majority of cases of myocarditis and pericarditis in adolescent and young adult males occur within a week of receiving the second dose of a COVID-19 mRNA vaccine. 19.
However, it can occur after the first dose or after a booster dose.
Myocarditis remains a very rare complication of mRNA vaccines, affecting around one in 50,000 people, Lloyd-Jones said.
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“The chances of having serious complications (heart, lung, brain and others) remain much greater from catching the COVID-19 virus itself if you are not vaccinated, than from this rare complication of the vaccine. “Lloyd-Jones told Fox News Digital.
“People should be aware of the risks and weigh them against the much greater risks of complications in getting the covid19 virus and make an informed decision, using information from reliable sources,” he added.

The majority of rare cases of myocarditis and pericarditis in adolescent and young adult males occur within one week of receiving the second dose of a COVID-19 mRNA vaccine. (Stock)
As for young men who will develop the disease after the vaccine, Lloyd-Jones said it appears to be an “idiosyncratic reaction” that cannot be predicted.
“It only seems to happen soon after vaccination, within days to weeks,” he added. “He was not seen later to my knowledge.”
The study had limitations
The study authors pointed out some limitations, primarily the small size of the patient group.
“Although our cohort of LNP-mRNA vaccine-associated myopericarditis is one of the largest studied to date, and our hypothesis is consistent with published reports from other patients, the number of participants remains limited to draw conclusions. general,” the researchers wrote in the results.
“The chances of having serious complications remain much greater by catching the COVID-19 virus itself.”
There was also some variation in age, vaccine dose and duration after vaccination, they noted.
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Moreover, we do not know how genetics may come into play at risk for myocarditis, the authors said.
The study also lacked biopsied samples of heart tissue.
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Fox News Digital has reached out to the Yale researchers for comment.