https://www.telegraph.co.uk/ne....ws/2025/12/10/how-co


How Covid vaccines can cause heart damage

Immune systems triggered by mRNA jabs may inflame cardiac cells, with young men most at risk, scientists find
Sarah Knapton
Science Editor Sarah Knapton
10 December 2025 7:56pm GMT
Related Topics

Coronavirus, Vaccines, Heart health, Scientific research, Moderna, Pfizer

Covid mRNA vaccines can cause heart damage by triggering immune cells to go on the attack, scientists have found.

More than 2,000 people in Britain suffered inflammation of the heart [myocarditis] or heart lining [pericarditis] following vaccination, with young men particularly vulnerable.

The majority of cardiac problems were caused by mRNA jabs, such as Pfizer and Moderna, which delivered a blueprint of the Covid spike protein to cells.

Now Stanford University has found that the immune system can lock on to the foreign RNA from the vaccine, which triggers a fierce response and in some cases can inflame heart cells. It is likely to be a problem with other mRNA jabs, they warn.
Nurse giving young man Covid-19 vaccination
Young men are particularly vulnerable to heart inflammation caused by mRNA vaccines, scientists say Credit: Monty Rakusen/Digital Vision

Prof Joseph Wu, the director of Stanford Cardiovascular Institute, said: “Overall, our study shows that the vaccine serves its intended purpose of inducing memory immune response against future infections.

“However, in the acute phase, the vaccine can induce cytokine – immune signal proteins – release that makes the patients feel bad, for example, fever, muscle pain and joint aches that are usually relieved by ibuprofen, but very rarely can cause myocarditis.

“Your body needs these cytokines to ward off viruses. It’s essential to immune response but can become toxic in large amounts. In the future, one can design better/safer vaccines that preserve the long-term memory response and mitigate the short-term cytokine release.”

Scientists have been excited about mRNA vaccines because they can be altered rapidly to keep up with new or mutating diseases, simply by altering the blueprint they carry.

They instruct cells to make a part of the pathogen, but in rare cases, they can cause an overreaction from parts of the immune system, which are on the hunt for foreign DNA or RNA, which typically comes from viruses.
Filled vials of Covid-19 vaccine on a production line machine
The mRNA vaccines can be altered rapidly to keep up with new or mutating diseases Credit: iStockphoto

Vaccine-associated myocarditis occurs in about one in every 140,000 people vaccinated after a first dose and rises to one in 32,000 after a second dose. Incidence peaks among males aged 30 or below, at one in 16,750 vaccinations, but is still very rare.

Symptoms include chest pain, shortness of breath, fever and palpitations within one to three days after a shot. Recovery is usually quick, but in rare cases it can lead to hospitalisation and death.

Recent studies have shown that the short-term risk of heart problems is higher than Covid in the first week, but over time, people who catch coronavirus are at greater risk from the conditions, leading experts to recommend that vaccination is still safer.

Recommended
The true tragedy of the Covid-19 vaccines
Read more

For the study, scientists analysed blood from patients who were vaccinated against Covid-19, some of whom developed myocarditis.

Comparing those who developed the condition with those who did not, they noticed high levels of two signalling proteins in the blood of those with myocarditis, which operate like a tag team, ramping up the immune system and damaging the heart.

Prof Wu said he had a hunch that an anti-inflammatory derived from soy called genistein could help prevent such damage.

In a series of experiments, cells and animals were treated with genistein, which prevented much of the damage caused by vaccines.

“Genistein is only weakly absorbed when taken orally,” added Prof Wu. “Nobody ever overdosed on tofu.”

The research was published in Science Translational Medicine.