An mRNA-based COVID-19 vaccine has proven to be highly safe and effective against a deadly pandemic. However, as with all medical interventions, there are some risks. One is that very few people who get the vaccine develop inflammation in and around the heart, a condition called pericarditis, which is myocarditis, pericarditis, or a combination of the two. occurs mainly in men in their teens and early twenties, most often after the second dose of the vaccine. Fortunately, symptoms are usually mild and resolve on their own.
These diseases are rare and mild, the study concludes, and experts agree that the benefits of vaccination outweigh the risks. In fact, he is significantly more likely to develop myocarditis or pericarditis from COVID-19 infection than from the COVID-19 vaccination.according to Large scale survey in 2022 In a study led by researchers at Harvard University and the Centers for Disease Control and Prevention, the group with the highest risk of myocarditis and pericarditis after vaccination (men aged 12 to 17) had 100,000 per 100,000 after the second vaccination. We identified 35.9 cases (0.0359%). After his COVID-19 infection in the same age group, the infection rate nearly doubled to 64.9 cases per 100,000 (0.0649%).
Still, the terms are a bit of a puzzle. Why do a few people develop this complication after vaccination? Why does it seem to affect only the heart? How does the damage occur? And what does that mean for the many other mRNA-based vaccines currently in development?
New research in Science Immunology Provides some fresh insights. The study, led by researchers at Yale University, delved into the immune response of 23 people, mostly men, aged 13 to 21, who developed myocarditis and/or pericarditis after vaccination. rice field.
Possibility of probing
Since the rare phenomenon was first noted, immunologists and other experts have suggested that vaccines promote several abnormal immune responses that explain the inflamed heart, including autoimmune and allergic reactions. We have hypothesized that it is possible, and new research has ruled out some of them.
The researchers used blood samples from a subset of patients to examine immune responses and compared them with blood samples from corresponding vaccinated controls. They first compared antibodies to SARS-CoV-2 and found no evidence of an “excessive” or enhanced antibody response to the virus that might explain myocarditis and pericarditis.2 The anti-SARS-CoV-2 antibody responses in the two groups were comparable, and those in the heart patients were comparable, if not slightly blunted.
The researchers next screened for autoantibodies—antibodies stimulated by vaccines that were misdirected against the human body instead of the virus. Scanned for autoantibodies against over human proteins and molecules. Researchers focused on his more than 500 probes associated with heart tissue. They found no relative increase in the number of autoantibodies compared to controls, suggesting that an autoimmune reaction was unlikely.
The researchers then took a broad, unbiased approach to compare immune response profiles between patients and controls. They found different immune signatures between the two groups, as patients exhibited elevated levels of immune signaling chemicals (cytokines) associated with acute systemic inflammation. And these cytokines were accompanied by a corresponding elevation of inflammatory cell responses, especially cytotoxic T cells. Furthermore, the gene expression profile of these T cells showed their potential to cause cardiac tissue damage.
protracted question
Taken together, the researchers concluded that in these rare cases of myocarditis and pericarditis, it is most likely that the vaccine is promoting a generalized and vigorous inflammatory response that leads to heart tissue inflammation and damage. concluded that it is a high explanation for
“The immune systems in these individuals are a little too activated, producing an overabundance of cytokines and cellular responses,” senior study author Carrie Lucas, a professor of immunobiology at Yale University, said in a statement. I got
While this study provides possible answers to the “how,” it does not answer all questions. For example, why a young man? And why a heart? Researchers note that young men, especially in their late teens, are the most common group to commonly develop myocarditis from any cause. Medical experts do not know why this is so, but hypothesize that it may be due to a combination of environment, genetics, and hormones. especially testosteroneAs to why the heart appears to be peculiarly damaged, co-author Akiko Iwasaki, who is also a professor of immunobiology at Yale University, says the heart is working all the time and has limited tissue regeneration potential. I guessed it was because prone to inflammation.
Finally, it remains unclear what exactly within the vaccine is causing the enhanced inflammatory response, namely the SARS-CoV-2 mRNA within the vaccine or the lipid nanoparticles carrying the SARS-CoV-2 mRNA itself. Preliminary evidence suggests that both ingredients can provoke an inflammatory response by themselves. However, researchers will need more data and studies to understand this and further optimize the vaccine’s safety profile.
So far, the finding that an inflammatory response is behind cases may guide treatment and prevention. Dosing interval of mRNA vaccine It can reduce the chance of myocarditis and pericarditis in young men. But new research may offer some relief if inflammation does occur.
