A stunning new study published in the American Heart Association’s flagship journal Circulation last week has confirmed what many independent researchers have long suspected: the mRNA vaccine itself — not COVID-19 infection — triggers myocarditis through devastating autoimmune attacks on the heart.
Researchers from Queen Mary University of London, Landspitali University Hospital in Iceland, and several European institutions found that people who developed acute myocarditis or pericarditis after mRNA vaccination showed a distinct pattern of immune activation not seen in COVID-19 patients.
The paper, titled “Combined Adaptive Immune Mechanisms Mediate Cardiac Injury After COVID-19 Vaccination,”reveals that T-cells from vaccine-injured patients began attacking the body’s own heart proteins because parts of the vaccine-encoded Spike protein closely mimic human cardiac tissue.
“T cells from patients who developed myopericarditis after mRNA vaccination recognize vaccine-encoded Spike epitopes homologous to those of cardiac self-proteins,” the authors wrote.
In plain English, that means the immune system, trained to recognize the vaccine’s Spike protein, mistakes parts of the heart for the virus — a process known as molecular mimicry.
One of the Spike fragments identified in the study mimics a potassium channel (Kv2) found in heart muscle cells. When mice were injected with that specific Spike fragment, they developed the same kind of myocarditis seen in humans after vaccination.
Crucially, this autoimmune reaction did not appear in patients who caught COVID-19 naturally, only in those who received the mRNA shot.
Why the Vaccine Reaches the Heart
The researchers also discovered that the mRNA vaccine’s unique biodistribution — the way its nanoparticles spread throughout the body — may allow the immune system to “home in” on the heart.
They identified a population of T-cells expressing a receptor called cMet, which acts like a GPS signal guiding the immune attack specifically toward cardiac tissue.
Blocking this cMet pathway prevented the heart-directed immune reaction in laboratory models — a finding that could help explain why myocarditis cases cluster around young men and occur most often after the second or third shot, when immune “priming” is strongest.
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| FImmunization with the mRNA-1273 vaccine induces acute myopericarditis in susceptible mice. |
An Autoimmune, Not Infectious, Process
The study authors conclude that post-vaccine myocarditis is an autoimmune disorder triggered by Spike mimicry, not a direct result of viral infection or contamination.
In other words, the body’s own defenses — super-charged by the mRNA platform — turn against the heart.
Implications
While the authors present their findings as a step toward “safer mRNA designs,” the implications are far more serious. The research establishes a clear mechanistic link between the mRNA vaccine and heart inflammation — something health officials once dismissed as “rare and mild.”
This peer-reviewed evidence, published by the American Heart Association itself, challenges the repeated claim that “COVID causes more myocarditis than the vaccine.”
In this study, COVID patients did not exhibit the same autoimmune T-cell behavior — only the vaccinated did.