Just 0.7% of Major League Baseball employees tested positive for antibodies to Covid-19. The small number of positive tests, came as the league continues to plan to start its delayed season.
Researchers received 6,237 completed surveys from employees of 26 clubs. The tests were administered in mid-April. About 70% of those who tested positive reported being asymptomatic, 2.7% had a fever, 14% had a headache and 0.9% had temporarily lost their sense of smell or taste. Of those who tested positive 8% reported a cough, compared to 9% who tested negative.
Antibodies are produced by a person’s immune system if they have been infected by a virus. These tests are different than the polymerise chain reaction (PCR) tests used to detect active infection.
Dr Jay Bhattacharya of Stanford, one of the study’s leaders, said the prevalence of the antibodies among MLB employees was lower than for the general population during testing in New York, Los Angeles, the San Francisco area and Miami.
“I was expecting a little bit of a higher number,” Bhattacharya said. “The set of people in the MLB employee population that we tested in some sense have been less affected by the Covid epidemic than their surrounding communities.”
The survey was not representative of the US population. Sixty percent of those who took part were male, and 80% were white. Most of those surveyed were also either highly paid, professional athletes or white collar workers.
“There’s a socioeconomic gradient where poorer populations are facing Covid infections at higher rates,” Bhattacharya said.
Over 95% of the participants were under 65 and few reported underlying health issues. The prevalence of positive tests for antibodies was higher in areas that have been harder hit by the virus, such as New York.
“This is a special population,” Bhattacharya said. “It’s not it’s not representative of the American population at large. But it’s an important population because it allows us to get a peek at the nationwide prevalence.”
Bhattacharya called the results “both good and bad news” because they showed the virus has not spread widely in MLB but, on the other hand, still has many players left to target. Daniel Eichner, another of the study’s leaders, said results could mean MLB employees had been diligent in use of personal protective equipment, such as masks.
“If this population was social isolating and practicing good PPE, then it shows that that worked and it didn’t get the spread in there,” Eichner said. “And then the flip side of that is that means it’s worked well, then they keep doing it.”
Bhattacharya said the low number of positive tests showed there is a still long way to go in the pandemic. “It’s very clear,” Bhattacharya said, “that the epidemic is still in the early stages throughout the country.”
While the percentage of Los Angeles Angels employees with positive tests was the highest among teams, the error margin is too high to draw results because just 123 tests were included from the team.