Researchers studying mRNA COVID-19 vaccines say they may have found a possible explanation for the rare cases of myocarditis reported mostly in younger males. Although the vaccines are considered highly effective and generally safe, scientists have continued investigating why a small number of people developed heart inflammation after vaccination. A Stanford Medicine–related study points to immune signaling proteins called CXCL10 and IFN-gamma as possible contributors to this reaction.

According to the research, some immune cells exposed to vaccine components produced these inflammatory signals, which were linked to reactions that could affect heart tissue. The findings provide a possible biological explanation for how myocarditis may occur in rare situations after vaccination, helping researchers better understand the condition and how it develops.

Scientists stressed, however, that the overall risk remains extremely low. They also noted that COVID-19 infection itself carries a much higher risk of myocarditis and other serious complications than the vaccines do. The study was focused on understanding the mechanism behind these uncommon cases, not questioning the overall safety and effectiveness of vaccination.

Researchers also found that blocking the inflammatory signals reduced heart-related damage in laboratory and animal experiments, although it did not stop the immune response completely. This suggests there may eventually be ways to lower the risk while still keeping vaccine protection strong.

The study further mentioned that compounds such as genistein showed “some protective effects” in experimental models. Still, scientists emphasized that the research is in its early stages and “not an immediate treatment recommendation,” meaning more studies are needed before any medical conclusions can be made.