Background: During COVID-19 pandemic, several vaccines have been developed such as mRNA vaccines. However, acute pericarditis and myocarditis/myopericarditis cases have been described after mRNA vaccination. The mechanism for the development of cardiac involvement is unknown. Potential mechanism for oxidative stress associated with vaccine-induced heart involvement is unidentified. This study aimed to examine the role of oxidative stress and the heart involvement in young adults vaccinated with COVID-19 mRNA vaccines.