Arthur L. Caplan is the founding head of the Division of Medical Ethics at NYU School of Medicine in New York City and Lee H. Igel is a clinical professor in the NYU Tisch Institute for Global Sport.The omicron Covid-19 variant is spreading across professional sports faster than at any time since the start of the pandemic. Scores of positive cases within teams are leading leagues to postpone games and adjust health and safety measures. The shut down of sports in March 2020 jarred many people into realizing the new coronavirus was something more than a seasonal bug. Now, with infection rates surging again, what guidance could pro sports provide to the general population?Scanning the big-time sports playing grounds, it isn’t hard to see that omicron is quickly changing the game. Large numbers of players are being sidelined by positive test results that send them into Covid safety protocols. Handfuls of games are being postponed because of depleted rosters and concerns over viral spread. Stadiums and facilities are limiting access due to sharp rises in indoor exposure between teammates, team personnel, and the broader community.Until now, major leagues in the United States have been able to play their seasons mostly uninterrupted. Part of that owes to 95% or more of players in the National Football League, National Basketball Association, Women’s National Basketball Association, National Hockey League, Major League Soccer, and National Women’s Soccer League reportedly having been vaccinated. Players who choose to not be vaccinated, including prominent quarterbacks who say they are “immunized” by developing natural antibodies after recovering from Covid, are supposed to adhere to more frequent masking and testing protocols. The leagues have also mandated that team coaches, staffs, and personnel executives be fully vaccinated. But the highly-contagious omicron strain seems to be getting the better of those game plans. The NHL, currently in the middle of its regular season, is pausing all activities across the league until at least Sunday because of Covid outbreaks among teams. The NFL is postponing games, as tens of players, including stars and starters, on different teams test positive each day. The NBA has postponed a couple of games lately, but seen several big-name players placed into the league’s Covid protocol. The English Premier League, one of the most followed sports competitions in the world, had to postpone more than half of its 10 matches scheduled this past weekend because of Covid-related issues. Executives were considering a “firebreak” shutdown of the league, but instead decided to push enhanced safety measures for the time being.Last year, the NBA suddenly suspended its season after one player on one team tested positive. Major leagues in the U.S. and Europe followed suit, one after the other, within hours. If the spread of a virus was knocking out sports, what was it going to mean for the rest of society? And what lessons could be drawn from the way that sports was responding to the Covid crisis?Since then, there has been a great deal of learning about the virus, its behavior, and how to manage it. A chunk of that knowledge owes to scientists studying data generated by activities of sports leagues, teams, and players throughout the pandemic. As omicron takes its course and organizations across pro sports are once again resorting to intense Covid prevention procedures, they can offer guidance to help keep everyone safe and keep illness at bay. The first cases of the omicron variant were announced about a month ago. It is still too new and moving too swiftly for medical professionals, health researchers, and surveillance systems to have a precise read on its symptoms and severity. But it is clear that the variant is being transmitted quickly, easily and widely. Breakthrough infections are happening everywhere. A study at the University of Hong Kong indicates this may be due to Omicron harboring and replicating up to 70 times faster nearer the mouth, nose, and throat compared to earlier virus strains.It is also clear that vaccines matter. While omicron appears to evade prior immunity and vaccinations don’t prevent a person from contracting Covid, staying up-to-date with boosters helps stave off the severe symptoms that lead to hospitalization. Research at Imperial College London estimates that recovery from past infection offers 19% protection against omicron, two-dose vaccine provides 20% protection and a booster dose gives you between 55% and 80% protection.One thing is already certain, though: omicron is highly contagious. It is certainly enough so that pro sports, with the billions of dollars and billions of fans tied to its games, are changing their strategies.People and places in pro sports are among the most-monitored anywhere. Pro athletes are young and healthy people with access to top medical care whenever they need it. Even if most of them who contract Covid turn out to be asymptomatic or have mild symptoms, they could still transmit the virus to others in the community who may not be so lucky. Hospitals are already being overwhelmed with sick patients. So, caution and prevention are key.The public can take some cues from some of the better ways that leagues and teams are managing the situation.The NFL, for example, has already announced mandatory mask-wearing, social distancing, and takeaway meals when indoors at team facilities. Virtual meetings are making a comeback. There are also restrictions on activities such as no dining out on the road. The NHL has similar protocols in place and is increasing the frequency of testing to daily instead of every three days.Vaccines are also part of the plan. The NBA, for example, has included a provision that bars team staff from in-person interaction with players, coaches and referees if they don’t get a third dose or booster. The NFL has also mandated that coaches and team staff who work closely with players are required to receive a booster shot.Labor agreements mean that leagues and teams cannot mandate players to get vaccinated. They can only encourage them to do so. They can also make sure that health and safety protocols are in place and being adhered to, even if more than a few players are fed up with the protocols and want them eliminated.Messaging also matters. In the Premier League, Liverpool manager Jurgen Klopp and Manchester City manager Pep Guardiola are urging players and fans to cede to science by getting a third shot. If science is good enough to be used for putting players on the field in top form, then the same goes for public health. Chelsea Football Club is partnering with the National Health Service for the latest in a series of pop-up mass vaccination centers at Stamford Bridge stadium in London.Pro sports leagues don’t take lightly the decision to postpone games. Beyond the money, there is a mind-boggling list of logistical, organizational, and media issues to contend with for each game. So, they opt to just go about changing the schedule, even for competitive reasons such as a team needing to call-up reserve players because regular players at one position or another are out due to Covid. A virus outbreak like we are seeing with omicron, however, shifts the decision-making to one based on public health from one based on competition and ratings.Sports are an economic and cultural engine the world over. People pay attention to sports for much more than fun and games. From the earliest moments of the pandemic, pro sports was considered “non-essential,” yet has shown time-and-again to be quite vital. The lessons are there — test, mask, vaccinate, isolate, stay remote when you can, cancel activities if you must. Let’s hope fans and public officials are paying attention.