Researchers studying mRNA COVID-19 vaccines say they have identified a possible biological mechanism that may help explain rare cases of myocarditis, particularly in younger males.

While the vaccines are widely considered highly effective and generally safe, myocarditis has been observed in a small number of cases, and scientists have been trying to understand why it occurs.

A Stanford Medicine–related study suggests that immune signaling proteins called CXCL10 and IFN-gamma may be involved in triggering inflammatory responses.

In lab and animal models, certain immune cells exposed to vaccine components produced these signals, which were linked to inflammation that could affect heart tissue.

These findings offer a potential explanation for how rare heart inflammation cases might develop after vaccination.

However, researchers emphasize that the overall risk remains very low and that COVID-19 infection itself carries a higher risk of myocarditis and other complications.

The study also showed that blocking these inflammatory signals reduced heart-related damage in experimental settings, though it did not eliminate the broader immune response.

While compounds like genistein showed some protective effects in models, scientists stress that this is early research and not an immediate treatment recommendation.