HT15. COVID-19 vaccinated individuals may be ill…See more

Examination of the mice’s heart tissue revealed infiltration by macrophages and neutrophils, another class of aggressive immune cells. This kind of immune cell invasion into heart tissue is also observed in human patients with post-vaccination myocarditis. The problem with these cells is that, in their eagerness to fight perceived threats, they can cause collateral damage to healthy tissue — including the delicate cells of the heart muscle.

When the researchers blocked the activity of CXCL10 and IFN-gamma, this infiltration was substantially reduced, and cardiac troponin levels dropped, even as the overall immune response to the vaccine remained largely intact. This was a critical finding: it suggested that the inflammatory damage to the heart might be separable from the vaccine’s protective immune function.