Before the COVID-19 pandemic began, myocarditis affected somewhere between 1 and 10 people per 100,000 each year for a variety of reasons. Rates of non-pandemic related myocarditis are typically highest in males 18 to 30 years old who are active, healthy individuals.
These rates have skyrocketed since March 2020 with approximately146 cases for every 100,000 people, according to the . Men, older adults over the age of 50, and kids aged 16 and under have the highest rates of risk.
Simply put, COVID-19 can result in dangerous and lasting heart damage and that is triggering much higher rates of myocarditis than are normally found in a typical population.
https://www.beaumont.org/health-wellness/blogs/myocarditis-risk-associated-with-covid-19-infection