Scientists discover how Covid shots cause deadly heart damage as officials launch probe into vaccine-linked deaths | 11 Dec 2025 | Scientists at Stanford University have revealed how the mRNA Covid vaccines can cause damage to heart cells. Experts have long sounded the alarm over myocarditis, an extremely rare complication of the vaccine that causes inflammation of the heart muscle. Data show about one in 125,000 children and adults under 65 who were vaccinated against the virus between 2023 and 2024 developed the condition. Among men and boys under 25 years old, however, the rate rose to one in 250, or 475 per 125,000. The FDA has said it is now conducting a thorough investigation into reports of deaths in both children and adults that are thought to be linked to the Covid vaccine… Earlier this month Dr Robert Redfield, who headed the CDC during Trump’s first term, said he did not support the continued use of mRNA Covid vaccines.