Cause of rare myocarditis in young man found after second SARS-CoV-2 mRNA vaccination

Over the past three years, the safety of SARS-CoV-2 mRNA vaccines has been thoroughly demonstrated. However, like most medicines, these vaccines can have side effects that are uncommon for some people.

now, study at scientific immunology identifies two processes behind one such side effect called pericarditisThe study, which included the analysis of blood samples from 23 young patients, found that vaccine-associated myocarditis was not caused by an autoimmune or allergic reaction. likely due to signaling from sex chemicals, cytokineand expansion of activated leukocytes.

“Our findings do point to inflammation-induced cardiac damage and rule out the development of autoantibodies or excess anti-SARS-CoV-2 antibodies in mediating disease.” Stated. Akiko Iwasakicorresponding author of the study, Sterling Professor of Immunobiology and Molecular, Cellular, and Developmental Biology at Yale University, and Howard Hughes Medical Institute investigator.

myocarditis and pericarditisor pericarditis, has been observed very rarely in a subset of adolescents and young adult males after a second dose of SARS-CoV-2 mRNA vaccine. We provide results that support other studies that have investigated how to fine-tune them optimally.

“Our results are consistent with what others have found in clinical data, given the timing of the vaccine,” he said. Carrie Lucas, corresponding author of the paper, and associate professor of immunobiology at Yale University. Her clinical study found that “separating second doses of the vaccine reduced the amount of cytokines and bystander immune activation, potentially reducing the risk of myocarditis.” ,” she explained.

Beyond mRNA vaccines, myocarditis and pericarditis can occur during viral infections such as COVID-19 itself, and usually cause much more severe damage.

“[This study is] A basic understanding, not just vaccines, but even viral-induced myocarditis, is critical for how to early detect and treat these events in the future. Lucas.

Patient search

of The development of mRNA vaccines began decades agoIt begins with the discovery of mRNA in the 1960s. Around 21:00^st During the century, scientists began investigating how to safely inoculate people with modified viral mRNAs as an alternative immunization strategy to train the immune system to recognize pathogenic viruses. These research efforts paid off when the COVID-19 pandemic began, leading to today’s FDA-approved SARS-CoV-2 mRNA vaccine.In the three years since, countless studies have modern and Pfizer/BioNTech Vaccines have established safety.

Because of this safety, it has been difficult for scientists to find enough patients to experience vaccine-associated myocarditis. It has been noted that it is male and spans puberty to adolescence on average. From these observations, researchers theorized that age, especially youth, plays a role.

This hypothesis is supported by existing evidence such as: Children and adolescents have their own immune system They respond differently to pathogens than adults.

“They’re not just little adults,” said Lucas, repeating a refrain she noted as common among pediatric professionals.

Gender differences such as testosterone production levels and genetic factors were also suspected to contribute to this mostly male subset of cases of vaccine-associated cardiac inflammation.

“Testosterone has been tested in animal models of myocarditis and exacerbated myocarditis and dilation of the heart,” said Iwasaki. . innate immune response As well as many other factors. ”

By embarking on this new study, Iwasaki and her colleagues in the fields of immunology, pediatrics, and cardiology have identified rare cases of vaccine-associated pericarditis, and the potential for making pericarditis overall even rarer. I wanted to collect sensitive information.

pathway to disease

To learn more about how pericarditis can develop after a second SARS-CoV-2 mRNA vaccination, Lucas and team obtained blood samples from 23 previously healthy patients. Analyzed. These patients initially presented with symptoms including but not limited to chest pain, palpitations, myalgia and headache. These symptoms began 1-4 days after her second dose. After admission, the patient was treated as follows: NSAIDs and steroids and began to recover within 1 to 6 days.

By examining the sera of these patients, researchers found that the immune system of these patients showed increased cytokine signaling. This increased signaling, characterized by inflammatory protein factors such as IL-15 and IL-1, promoted leukocyte proliferation. These factors may one day be used as diagnostic biomarkers for pericarditis.

“If we could go back in time and look at these patients before they came to the hospital, we might have detected these factors earlier. “It will give us some sort of biomarker to detect potential onset.” [create] Faster detection method. It’s a necessary study. ”

The author also macrophage There was a predisposition to cause fibrosis, a condition that involves tissue scarring. When it occurs in heart tissue, it can seriously affect organ health. Despite the surge in all these immune cell populations, there was no evidence to suggest that vaccine-induced antibodies were the cause.

“The innate immune system is activated in these healthy young men who overproduce these cytokines. Cytotoxicity T cells overreact and cause tissue inflammation,” Lucas said.

Over the next few years, more mRNA vaccines may continue to be developed against a variety of pathogens, potentially including: Influenza universal vaccineThis new study may help public health professionals improve strategies for administering future mRNA vaccines to many demographics. It may also help efforts to better treat

“We basically used every immunology tool to see what was going on. We hope it will be useful for detection and treatment,” said Iwasaki.