Kansas

... previously infected athletes who had mild or no clear symptoms.

https://www.the-scientist.com/news-opinion/college-athletes-experienced-heart-damage-after-covid-19-study-67929

When they imaged the hearts of more than two dozen of Ohio State University players using cardiac magnetic resonance (CMR), they found evidence of myocarditis in 15 percent, while a further 30 percent had cellular damage or swelling that could not be linked definitively to the condition.

Those percentages might make a Republican exclaim, "So what? That can happen with any viral infection!"

Well, here's what. It's not very common at all!

While myocarditis is a rare condition—affecting roughly 22 out of every 100,000 people each year—it is nevertheless a recognized cause of death among professional athletes, even in the absence of previous heart trouble. A 2015 study found that among NCAA athletes who died of a sudden cardiac event, 10 percent experienced myocarditis, and a Myocarditis Foundation report found that the condition causes 75 deaths per year in athletes between the ages of 13 and 25.