Now the league is joining the fight against the virus in a way that could help society get going again.
Of the league's 30 teams, 27 are taking part in a nationwide study involving up to 10,000 people who will be given tests to detect COVID-19 antibodies. Those antibodies appear as part of the immune system's response to the coronavirus. The test results, if positive for antibodies, can show if people were infected but didn't show symptoms — and, possibly, if they're now immune to the disease.
Researchers say the study will help provide important data about the infection rate of COVID-19.
"It's very hard to set public health policy without knowing the infection rate," says Dr. Daniel Eichner, who is involved in the study, "and so this will contribute to that important information. You hear people, governors and other politicians talking about getting more information to understand the infection. Well, this will specifically address that."
From GMs to hot dog vendors
Eichner has a Ph.D. in viral immunology, but it's his work with performance-enhancing drugs that laid the foundation for baseball's involvement. He's the president of the Sports Medicine Research and Testing Laboratory — it's a World Anti-Doping Agency-accredited lab that does drug testing for many sports, including baseball.
Eichner and fellow researchers at Stanford University and the University of Southern California knew there was a need for widespread and quick data collection, and the MLB fit the bill.
"So we went to MLB," Eichner says, "and said, 'Hey we're doing this study, would you like to partner with us,' because they had nationwide coverage. They have all the different teams, in all major cities around the country and even in North America. And they didn't even hesitate. They said: 'Absolutely.' "
Baseball offered not only geographic spread, but a wide variety of subjects as well: from older executives in the higher risk category to 20-something baseball players. Most of the thousands of MLB employees in the study, though, are not pro athletes.
"All the way from general managers to hot dog vendors," Eichner says, "we're going to get a wide population."
"Without baseball, if we do this through regular academic channels, this study would take months if not a year to set up. It was a very unique opportunity to be able to harness all of the MLB community to get this nationwide coverage in such a short period of time."
For baseball, no hurry to return
Whichever major professional sport starts up first amidst the coronavirus outbreak obviously will get most of the nation's attention. But Eichner and MLB officials insist there was no connection between baseball's involvement in the study and a possible effort to position itself so health officials might OK a quicker restart for the sport.
In an interview this week on Fox, Commissioner Rob Manfred said MLB is in no hurry to resume play, stressing the public health situation has to improve first. And when asked about the study, Manfred told USA Today, "We are proud to support important scientific research to expand the understanding of the virus."
Participants are given a simple test — a finger prick to draw blood — and the results are known in a few minutes. Eichner says MLB employees who test positive for COVID-19 antibodies will consult with team doctors.
According to an MLB official, Dr. Jay Bhattacharya, a professor of medicine at Stanford and one of those working with Eichner on the study, conducted a webinar with all the participating team medical staffs before the study began to walk through proper protocols. All study participants, including volunteers and consulting physicians, received written guidance about properly interpreting results, including what to do if a participant tests positive for COVID-19 antibodies.
Eichner says it's also important to point out the difference between the antibody tests and the testing that actually detects the virus. There's been a lot of controversy about the lack of adequate testing for the virus and criticism that the rich and famous, including professional athletes, are more likely to get access to testing.
"I don't want anyone getting confused that we're taking these test kits away from front-line workers," Eichner says, "because we aren't. These [antibody tests] are not used for diagnosis."
They are used to help detect antibodies and possible immunity to COVID-19. But there are caveats as testing becomes more prevalent, and not just with this study. Since at the moment such a small proportion of the population has been exposed to the virus, false positives, where a test result says individuals have antibodies to the virus when they really don't, are a problem. Science's understanding of immunity needs to improve as well.
But, as NPR science correspondent Richard Harris explains, "high-quality antibody tests will still be valuable in instances where individual false-positive results matter less. That would be the case for surveys of entire populations, where errors can be factored out. In these studies, antibody tests are being used to answer critical questions about where the coronavirus is and how prevalent it is. That information can help officials plan how to let normal lives resume — but across populations as a whole, rather than one person at a time."
Eichner and his fellow researchers agree.
"We can't even think about reopening parts of our economy," Bhattacharya told USA Today, "until we have that data. This study will help when and where it's safe to reopen."
Researchers in a hurry
Eichner says data collection will finish this week, in a day or two. After that, researchers will analyze the data, crunch the numbers and then write a paper for submission to a peer-reviewed journal.
"It'll be written very quickly," he says, adding, "We'll dedicate all our resources to get this in very fast. I would like to say from previous experience, we should have this submitted within a week."
Because while baseball won't rush back too early, Eichner says time is of the essence when battling this pandemic.
"This is well beyond the usual kind of sports stuff [our lab] normally does. This [study] is a really important piece to help drive public health policy."