Researchers from the University of Basel and University Hospital Basel have found evidence of temporary damage to cardiac muscle cells after COVID-19 booster vaccination.
The University of Basel, located in Switzerland, is one of the world’s oldest surviving universities. Founded on April 4, 1460, it is Switzerland’s oldest university, widely recognized as a top institution of higher learning in the country.
The interdisciplinary research team at Basel conducted the study to investigate the negative effects of booster jabs on cardiac muscle cells.
They measured cardiac troponin, a marker for damage to cardiac muscle cells, in the blood of 777 University Hospital employees three days after booster vaccination.
In 22 participants, they recorded elevated cardiac troponin levels, indicating damage to the cardiac muscle cells. Troponin is only detected in the blood when heart cells are killed and spill the protein out of the dead cells.
In the past, such a phenomenon has only been observed passively, especially in young men needing hospital treatment, and not actively investigated.
The study found evidence of damage in 2.8% of participants, which is approximately 800 times greater than the anticipated rate of 0.0035%.
“We found evidence of temporary mild damage to cardiac cells in 22 of the 777 participants—2.8% instead of the anticipated 0.0035%,” the researchers said. “So there’s slight damage to heart muscle cells in almost 3% of the cases, which shouldn’t be overestimated, but also not ignored.”
While symptoms of the damage include shortness of breath, fatigue, and possible pressure on the chest, they are “mild and non-specific,” according to the researchers.
Further investigation of the affected individuals showed that cardiac troponin values were back to the normal range in around half of them on the following day.
It is unclear whether prior infection with COVID would affect the likelihood of damage after booster vaccination.
It is also unknown what percentage of those infected with COVID suffer damage to cardiac muscle cells as a result of the virus.
However, more severe cases of COVID can damage the heart muscle, the researchers noted.
The study only examined the Moderna vaccine, as it was the only one available at the time.
It is not yet known what triggers the damage to the cardiac muscle cells.
It could be a side effect of the immune response, the mRNA technology, or specific components of the coronavirus used for immunization, necessitating more investigational studies.
The Basel study shows that mild damage to heart muscle cells after booster vaccination is significantly more common than previously thought.
However, the researchers still recommend vaccinating high-risk groups, including cardiovascular patients, though they advised against exercise in the first few days after the vaccination.
An FDA briefing document reveals that Pfizer added a drug used to treat cardiac arrest (heart attack) called ‘tromethamine’ to its vaccine.