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

IFN-gamma, in particular, is part of a core defense mechanism against viruses and other pathogens. It is essential to mounting an effective immune response, but when produced in large quantities, it can trigger inflammation that damages structural proteins within the heart muscle. This kind of heightened cytokine activity may affect organs beyond the heart as well, with preliminary evidence pointing to similar effects in the lungs, liver, and kidneys.

Wu also pointed out that myocarditis is not unique to mRNA COVID-19 vaccines — other vaccine types can also cause it, and COVID-19 infection itself is a more potent trigger. However, the intense public attention on COVID-19 vaccines has meant that even mild cardiac symptoms following vaccination are more likely to be investigated and diagnosed, creating a more complete picture of risk than exists for other vaccines.