2023-05-08 09:49:02
Myocarditis can be a rare but serious side effect of vaccination against Corona. Young men are particularly affected. Now US researchers have found the trigger. It wasn’t vaccine antibodies.
Are the Sars-CoV-2 vaccines developed within a year really safe? People have asked themselves this question over the past two years. At the latest after it became known that inflammation of the heart muscle (myocarditis) or the pericardium (pericarditis) had developed in some of the vaccinated people, there were strong doubts that the vaccination was harmless for all groups of people. Because especially young men between the ages of 13 and 29 were affected most often, although all cases were relatively mild, mostly healed by themselves and nobody died from it.
In a comprehensive study, US researchers have now analyzed the underlying processes in the immune system of those affected. The most important result: Neither the antigen of the vaccine – the spike protein of the Sars coronavirus 2 – nor the antibodies formed by the vaccination are the cause of the inflammatory reaction. Instead, it is a fundamental overreaction of particularly strong immune systems. And the risk of such an overreaction can be significantly reduced by changing the vaccination schedule.
35.9 cases per 100,000 vaccinations: Adolescent males are at greatest risk for myocarditis
Myocarditis after a Covid-19 vaccination is relatively rare. In Germany observed the competent Paul Ehrlich Institute 1.33 cases per 100,000 vaccinations with Biontech’s mRNA vaccine and 1.46 cases per 100,000 vaccinations with Moderna’s mRNA vaccine. In Israel, where only Biontech was used, it was 2.7 cases per 100,000 vaccinations.
But that Risk is distributed very differently. Data from the US agency CDC show that 12- to 17-year-old boys are at greatest risk, especially after the second vaccination. Here 35.9 cases per 100,000 vaccinations were observed. This is significantly more than was reported in previous studies.
Cytokines were the main triggers of inflammation
A team led by immunologists Akiko Iwasaki and Carrie Lucas from Yale University in the USA wanted to know why the side effect is particularly evident in boys. They took blood and sometimes also plasma samples from a total of 20 boys and three girls aged 13 to 21 who had developed myocarditis after a corona vaccination. In all those affected, the side effect was confirmed by imaging methods such as MRT or X-rays and the effects on the heart were examined in detail.
Just those Plasmaproben proved to be particularly valuable, because with their help the immune reaction to the vaccination could be reconstructed very precisely. It was found that specific messenger substances with which the immune system triggers inflammation were significantly increased, in this specific case the two cytokines IL-15 and IL-1. As a result, certain immune cells that were cytotoxic, i.e. attacked the heart muscle cells, were increasingly formed. In addition, certain macrophages were also activated, which also belong to the immune cells and which can repair and strengthen attacked tissue and thus contribute to the formation of scars.
Greater interval between vaccinations reduces risk of myocarditis
According to the analysis, both types of immune cells were not activated by a specific antigen – such as the Corona spike protein. Rather, there was a broad signal from the cytokines, i.e. the inflammatory messenger substances. The reaction was therefore not an allergic reaction to the vaccine and also not a consequence of antibodies whose formation was triggered by the vaccination, according to the authors of the study. Rather, it was a general overreaction of the very strong, because young immune system of the young men.
From this, the doctors conclude that the risk of myocarditis in the risk group increases significantly reduce if a longer interval is left between the first and second vaccination. The rate can be significantly reduced after just eight weeks instead of the four weeks recommended.
Prediction of myocarditis risk still not possible
However, only further studies can show whether there are certain biomarkers that indicate an increased risk of myocarditis even before vaccination. Author Akiko Iwasaki also emphasized at a press conference: “The observed effect does not only occur with the mRNA vaccines. There is a well-researched, similar reaction with a chickenpox vaccine. It was shown in members of the army at the time.” A so-called protein vaccine was used, which contained proteins from the chickenpox pathogen herpes.
This topic in the program:MDR TELEVISION | BRISANT | November 29, 2022 | 6:10 p.m
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#Immune #system #boys #myocarditis #corona #vaccination