The study, published in JAMA Cardiology magazine, was written by the leading medical officials in these leagues and emerged from the weekly conference calls these officials held at the start of the coronavirus pandemic in March 2020.

“We felt it was very important to share our best practices as we were all grappling with the same things,” said Gary Green, medical director of MLB and one of the study’s authors. “When we realized we had these numbers [of cases]We started talking to the various cardiologists who are working with our various leagues and players’ associations to develop a joint effort. “

The study, which was conducted using data from athletes who tested positive between May and October last year, found that athletes developed serious heart disease far below the general population. Although only 0.6 percent (five out of 789) of athletes had myocarditis or pericarditis, those conditions were found in more than 7 percent of all Covid-positive patients last year, according to a study published in Circulation, a journal of the American Heart Association .

“We did that because at the beginning of [the pandemic]It was clear that people hospitalized with Covid had a significant one [incidence] of heart disease, ”Green said in a telephone interview. “And we wanted to make sure that athletes who got excited get back to their sport and do it safely. … We wanted to see: Is it safe for [athletes] return, and what is the risk? We found that the risk is very, very small. “

Of the 789 athletes who tested positive for the coronavirus, 460 (or 58.3 percent) were considered symptomatic and the rest were considered asymptomatic. Only 30 athletes, 23 of whom were from the symptomatic group, were referred for additional heart tests, and only five were diagnosed with inflammatory heart disease: three with myocarditis or inflammation of the heart muscle and two with pericarditis or inflammation of the tissues surrounding the heart.

These five have been held off the sport for different periods of time, and some have since returned without incident.

“By the end of December 2020, none of the athletes who underwent cardiac screening and resumed full professional sporting activity had had clinical cardiac events,” the study concludes.

In the study, the professional athletes who were diagnosed with heart disease after being diagnosed with Covid-19 for data protection reasons were not named. However, at least two were publicly identified in news reports: Boston Red Sox pitcher Eduardo Rodriguez, who missed the entire 2020 MLB season after being diagnosed with myocarditis but is in spring training before the 2021 season, and Buffalo Bills’ Tommy Sweeney, who already had a broken foot when he was diagnosed with myocarditis in November and ended his 2020 season.

The study takes note of its inherent limitations, including its retroactive effect and the lack of a consistent methodology for screening and diagnosing subjects. the fact that it was written before the arrival of newer, possibly more infectious, and more effective coronavirus variants; and the youth and general fitness of his section in relation to the general public. In addition, 98.5 percent of the study subjects were men.

“We wanted to be very careful [to say] That doesn’t mean we can apply this to everyone else, ”said Green.

Still, according to Green, the study’s authors fulfilled their main task.

“One of the goals of all leagues has been to contribute to the literature and understanding of Covid,” he said. This study, he added, “does that.”