Cause of heart muscle inflammation discovered after corona vaccination

Endogenous anti-inflammatories

Robert Klatt

  • Cause in some cases mRNA vaccines against SARS-CoV-2 die Formation of antibodies against an endogenous anti-inflammatory agent
  • These antibodies cause an autoimmune reactionthe the inflammation of the heart muscle (myocarditis).

In individual cases, an mRNA vaccination against SARS-CoV-2 can trigger myocarditis. Now the cause of this rare vaccine side effect has been discovered.


Saarbrucken (Germany). Die mRNAvaccines versus SARS-CoV-2 trigger inflammation of the heart muscle (myocarditis) in about one to ten out of 100,000 cases. According to a report by the Austrian Federal Office for Safety in Health Care (BASG) especially young men. Fortunately, vaccination myocarditis is significantly milder on average than myocarditis after Covid-19.


Why the vaccination can trigger myocarditis in individual cases, researchers from the University of Saarland found out. According to their publication in New England Journal of Medicine they immunologically examined 40 patients who had developed biopsy-confirmed myocarditis after a SARS-CoV-2 vaccination. 214 vaccinated healthy volunteers and 125 volunteers who had developed heart muscle inflammation for another reason served as control groups.


Search for specific antibodies

Lorenz Thurner’s team looked for autoantibodies that also occur in people with a severe course of Covid-19 and in children with multisystem inflammatory syndrome (MIS-C). MIS-C, also known as Pediatric Inflammatory Multisystem Syndrome (PIMS), is a body-wide inflammation that occurs in some people after Covid-19.

Antibodies in vaccinated subjects with myocarditis

In the blood of three quarters (75%) of the vaccinated subjects with myocarditis, the researchers actually found an antibody against the body’s own anti-inflammatory interleukin-1 receptor antagonist (IL-Ra) in the blood. This is a molecule that blocks the docking sites of the inflammatory messenger interleukin-1 on the surface of the cells. This suppresses inflammatory immune reactions.

Scientists previously discovered that in some patients, even with severe Covid-19 courses, interleukin-1 receptor antagonists are deactivated by mistakenly formed antibodies. As Christoph Kessel from the University Hospital in Münster explains, the importance of interleukin-1 is also well known.

“Especially with regard to inflammation of the pericardium, heart muscle and blood vessels, we already know how important interleukin-1 is. However, our immune system normally regulates itself and highly potent interleukins in particular have natural opponents.”

Deposits disrupt the immune system

According to Thurner, the researchers were also able to clarify why the antibodies develop in men with vaccination-related myocarditis.


“Patients with myocarditis usually have an atypical form of IL-Ra with additional phosphorylation.”

The protein chain of the molecule therefore contains an additional phosphorus group, which is also found in a similar form in adults with a severe course of Covid-19 and children with MIS-C. However, this phosphorus group hinders the recognition systems of the immune system.

“The immune system then evaluates this as a foreign structure and mistakenly forms antibodies against it. This then neutralizes the important anti-inflammatory agent and thus promotes the effect of pro-inflammatory messenger substances.”

Why these accumulations only occur in some people is still unclear and should be investigated in further studies.

Vaccinations still useful

In addition, Karin Klingel from the University Hospital in Tübingen explains that vaccinations against SARS-CoV-2 still make sense despite their discovery.

“In this context, however, it must be made clear that vaccinations against SARS-CoV-2 have prevented countless serious illnesses and saved many lives. We strongly believe that the benefit of mRNA vaccinations, with the consequent protection against severe SARS-CoV-2 infection and serious complications, far outweighs the risk of mild myocarditis.”

New England Journal of Medicine, doi: 10.1056/NEJMc2205667

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