Skip to content 
Researchers at Stanford Medicine have identified a possible biological explanation for why a small number of people develop myocarditis after mRNA COVID-19 vaccination.
Although this reaction remains rare, scientists continue to study it closely to better understand individual immune responses. Health authorities emphasize that mRNA vaccines are safe and effective for the vast majority of people.
In many cases, myocarditis linked to vaccination has been mild to moderate, with most patients recovering fully. Studies also show that COVID-19 infection itself can carry a higher risk of heart inflammation.
The research focused on immune system differences between individuals who developed myocarditis and those who did not after vaccination.
Two immune signaling molecules—CXCL10 and interferon-gamma—were identified as potential contributors to inflammation in rare cases.