Image credit: Jonathan Dyer-USA TODAY Sports

COVID-19, the the illness caused by the novel coronavirus SARS-CoV-2, has become an urgent public health concern, and it’s fair to wonder how it will impact the game of baseball in 2020. As anyone who follows the sport beyond the borders of the United States is already well aware, that’s not a matter of if or when—the novel coronavirus has already made its presence felt in the baseball world. What remains to be seen is how it will affect the onrushing major-league season.

In Japan, Nippon Professional Baseball has prohibited spectators from both major league spring training games and minor league instructional games, and teams have been playing in empty stadiums. It remains to be seen whether the NPB regular season will begin on time, with or without spectators. 

South Korea has been particularly hard hit, second only to China in terms of numbers of infected patients. Seventy-five percent of the cases in South Korea are based in Daegu, home of the Samsung Lions. The KBO canceled all preseason games, an unprecedented step in the league’s 38-year history. The KBO has yet to make a decision regarding postponing the start of the regular season, maintaining the entire 144-game season will be played. As the start date of the KBO season remains uncertain, some of the major league players and coaches have remained in Australia and Fort Myers, Florida beyond their intended departure date. 

Taiwan has similarly altered its preseason, and the Chinese Professional Baseball League has already delayed the start of its regular season. Out of an abundance of caution, in February Taiwan imposed strict travel restrictions on people visiting the island. It should be no surprise that the final round of Olympic baseball qualifying games, intended to have been played there, have been postponed until June. Meanwhile, it remains uncertain if the summer 2020 Olympics in Tokyo will begin as planned.

Infectious diseases pay no mind to geopolitical borders and politics, so it is no surprise the United States has seen a sharp increase in the number of patients infected with the novel coronavirus. We can learn from other countries’ experience with this new virus, but we still need to answer for ourselves if actions such as those taken by overseas leagues, or even domestically in terms of reduced or canceled public events and movie-release schedules being altered is a matter of undue panic or warranted cautionary action. Before we can answer that question, particularly as it applies to congregating in baseball stadiums, let’s examine the cause of concern, and clarify some terminology. 

General public discussions have been referring to the coronavirus, but we need to note that it’s not the coronavirus, but a coronavirus. The coronavirus that has been in the news is a new species of coronavirus named SARS-CoV-2. For today’s discussion, we’ll generally refer to SARS-CoV-2 as “the novel coronavirus” or “the coronavirus.” 

While we don’t know much about this coronavirus, virologists have been studying coronaviruses for decades, and thus we have a general understanding of them. Coronaviruses are a family of RNA viruses which are a common cause of respiratory-tract infections throughout the world, and are implicated in everything from the common cold to severe acute respiratory syndrome (SARS). A physical feature of coronaviruses is the envelope, a fatty outer layer that surrounds the RNA within.

It’s important to distinguish between a virus and a disease caused by the virus. A person can carry a virus without being afflicted with a disease; a well-known example of this is Human Immunodeficiency Virus (HIV), which may develop into Acquired Immune Deficiency Syndrome (AIDS). SARS-CoV-2 can cause a respiratory disease which has been named COVID-19, a shorthand of sorts indicating that this is a coronavirus infectious disease originating in 2019. It’s likely that someone may be infected with the coronavirus SARS-CoV-2 without necessarily developing COVID-19, or presenting with any symptoms whatsoever. 

Symptoms of COVID-19 include a dry cough, fever, and shortness of breath; these symptoms are shared by a number of respiratory conditions, so it isn’t always immediately clear if a patient has COVID-19 or a different respiratory disease. Bear in mind that COVID-19 may present as just a mild respiratory impairment, and the vast majority of patients will recover. How a patient fares depends on a number of variables, including age and overall respiratory health. Interestingly, children have a much lower incidence rate of COVID-19, but it’s not clear if children are infected with the novel coronavirus and just don’t develop COVID-19, or if children are not infected. The infection’s mortality rate is still controversial and may not be confirmed for some time.

As far as treatment of COVID-19 or eradicating the coronavirus responsible for COVID-19, research is still in the early stages. Drugs used to treat other conditions are being repurposed for COVID-19, but that’s for treatment rather than prevention. Ideally, we would have a vaccine which would interrupt the virus itself, before the onset of disease, so as to prevent COVID-19 altogether. However, there is no vaccine for SARS-CoV-2, and there won’t be one anytime soon. There will not be a vaccine that will be relevant to the 2020 MLB season, and a vaccine that will be ready for the 2021 season would require an aggressive timeline and a lot of luck in terms of research and development. 

Knowing that there will not be a vaccine soon, it’s especially important that we, as individuals and as a society, take other preventative measures. This is where we come back to baseball. Perhaps the United States can learn from the steps taken by China, Japan, and Korea to determine a path forward. What actions is Major League Baseball currently taking in anticipation of the spread of the novel coronavirus, and what actions should they be taking?

An MLB spokesperson emphasized to Baseball Prospectus that the league is actively monitoring the situation while staying in contact with the Centers for Disease Control (CDC) and the Department of Health and Human Services (HHS) and is providing guidance to organizations based on CDC guidance and recommendations. MLBPA is also following CDC guidance, and the joint MLB/MLBPA Health and Safety Advisory Committee is making its recommendations based on their own public health and medical expertise. Additionally, MLB is actively conveying the information from national health experts, infectious disease specialists, and governmental agencies to all organizations. This includes guidance regarding disease prevention, good hygiene practices, and travel recommendations.

This proactive approach of open communication and dissemination of factual information and guidance from experts in public health is important for both emphasizing the importance of the situation and actions that can be taken, while also quelling fears. The open dialogue between MLB and MLBPA seems to have done just that; players have not publicly expressed concerns about the novel coronavirus or COVID-19. 

While player concerns about the Zika virus drove the cancellation of the Puerto Rico exhibition game in 2016, this is an entirely different scenario, both in terms of geography and disease. The 2020 International series are being played in locales that have not yet experienced a coronavirus outbreak, and as we noted previously, there is an age differential at work, with the more severe COVID-19 cases observed in elderly populations. It’s not unreasonable to think that the novel coronavirus probably won’t have as large an impact on young, relatively healthy athletes. It makes sense, then, that players do not seem worried at this time. Even players who reported to spring training from Asia have been in the US for three weeks and no cases have been reported within MLB organizations. 

Nevertheless, precautionary measures are always advisable. A clubhouse, where sweaty towels, humid showers, poor personal hygiene practices, and infectious particles mingle in close proximity, is a haven for disease where everything from norovirus to MRSA can thrive. Epidemiologist Beth Linas, PhD, MHS (Master of Health Science) notes that if one player is sick in the close quarters of a clubhouse, it is entirely possible other players will be exposed. The Red Sox are well aware of how an infectious disease can affect the on-field product. In 2017, several Red Sox players and staff were afflicted by influenza, which returned to Boston with the team. The flu affected players and staff through April, even after players and personnel self-isolated before breaking camp. 

When players are in close quarters for extended periods of time, contagious diseases are bound to spread, but teams can take precautions to minimize their impact, if not prevent them altogether. Infectious particles spread through a community using both fomite transmission and droplet transmission. Fomite transmission refers to the transmission of bacteria and viruses through non-porous surfaces, which can harbor infectious particles for hours or weeks. Virologists are still studying the novel coronavirus in this regard, but more generally, some coronaviruses can survive on hard surfaces for hours and even as many as nine days, depending on the surface. That’s potentially a series, if not an entire homestand, of games where lockers, weights, and trainers’ tables could be covered in coronavirus particles if they’re not repeatedly, thoroughly disinfected after every contact. 

Again, it’s not yet clear how long this particular SARS-CoV-2 coronavirus can survive on a hard surface. In any event, clubhouses would be wise to undergo a more rigorous, more frequent deep cleaning and disinfection than they would in the normal course of the season. Some spring training facilities have already implemented the latter protocol. The virus itself seems to be somewhat delicate due to its lipid envelope, so standard disinfectants (bleach, hydrogen peroxide, hand sanitizers containing at least 60 percent alcohol) seem to be sufficient to disrupt the structure of the virus, thereby disinfecting a surface. The novel coronavirus can also be spread through droplet transmission; the virus is found in saliva, mucus, and other respiratory fluids, which are projected through a sneeze or a cough. For droplet transmission, close contact is required in order to transfer the virus between people. Simply passing by someone for a short period (say, walking around on the concourse or standing on first base) probably would not be enough time to put someone at risk. But close contact is defined by the CDC as six feet, and if you’re sitting in the dugout or in the stands in close proximity to a carrier for an extended period of time, that may be sufficient for transmission. We can mitigate the hazards of droplet transmission by thoroughly washing our hands often and employing hygienic coughing and sneezing practices such as the vampire sneeze (or if you prefer, dabbing). Infectious disease specialist Amesh Adalja, MD, FIDSA, a Senior Scholar Johns Hopkins Center for Health Security, stresses, “This is not a containable virus and it will be with us for some time so individuals, including professional baseball players, will need to practice good hand hygiene and touch their faces less, especially when traveling.” In other words, this might be our new normal, and we should adopt these personal hygiene practices regardless of whether there is an active outbreak or not. 

While we all do our best to minimize droplet transmission by covering our sneezes and making liberal use of hand sanitizer, we can take additional measures by limiting physical contact with others. MLB has advised against handshakes, as well as suggesting that players not take baseballs and pens from fans.  Infected individuals can actively reduce the risk of exposing others through social distancing, such as staying away from public places or their workplace. This can be problematic even if you’re a baseball player; Dr. Linas notes that if players feel that they can’t miss a game or are concerned about a stay on the injured list, they put other players at risk. And this can extend to travel as well: There is some concern that as teams move from ballpark to ballpark, there will be the potential for transmission. However, while there’s a certain amount of risk to the playing staff, the odds are in their favor. Since major league baseball players travel on private transportation and major league clubhouse personnel are more than capable of decontaminating a clubhouse on a regular basis, players can minimize their risk of exposure.

Risk mitigation from the fan perspective requires additional considerations. It’s much easier to decontaminate a clubhouse than it is to treat an entire stadium. Any large gathering is an opportunity for a virus to spread, and a typical Opening Day attendance is a large gathering where fans will, for several hours, be sitting in enclosed or semi-enclosed stadiums containing over 40,000 people. For regular-season games with lower attendance, spacing spectators out throughout sections might be feasible. For a sold out Opening Day game, it would be impossible to maintain the CDC-recommended six feet of distance required to avoid “close contact” with someone who might be sick. 

Dr. Adalja emphasizes that even with increased handwashing and hand sanitizer stations at a stadium, “infection will not be totally avoidable at such mass gatherings.” This is further complicated by the fact that spectators may not know if the person sitting next to them is infected. Dr. Linas notes, “If reporting is accurate, some who are infected don’t feel sick, they don’t know they are sick, and they may infect others when they attend games. This becomes more concerning if older and immunocompromised [spectators] are at the game and are exposed.” Imagine a scenario wherein someone infected with the coronavirus—but not yet showing symptoms of COVID-19—attends an Opening Day game and, a week later, MLB and the CDC need to issue an advisory to the fans who were also in attendance that day. The league might be able to say the infected fan was sitting in a particular section or area of the stadium, but would also need to consider the time they spent in other parts of the stadium and even in the security line outside. 

Using the six feet “close contact” guideline from the CDC, sitting in a stadium—even an open stadium—packed for Opening Day may be a concern given the possibility attendees might be carrying coronavirus while being asymptomatic. This is why social distancing is a valuable public health tool: It’s not necessarily a quarantine that helps, but avoiding large crowds. This follows the World Health Organization (WHO) guidance, and some countries have already started prohibiting large gatherings. The CDC has issued guidance specifically pertaining to mass gatherings and large community events particular to the novel coronavirus and COVID-19. The CDC recommends event planners have provisions for refunds, which is a subtle way of saying, “Maybe it would be better if we didn’t.” As the disease’s spread and potential for harm in the United States becomes clearer, we may reach an inflection point at which the government may determine that the continuance of such events is no longer a question of an individual’s tolerance of risk but one of community safety and will act to curtail or limit them, as has happened overseas. We all love Opening Day, but the wisdom of having it remains an open question for now. To be clear, there is no cause for panic when it comes to attending baseball games, but there is cause for mature consideration of the risks until we know more.

Players can continue to play with little risk, but it seems fans take on a nontrivial amount of risk by patronizing a well-attended game. There are still a number of major league cities that do not have any documented coronavirus infections. It’s possible play could still continue in those cities, but the logistics of rearranging travel to play games only in cities not experiencing a coronavirus outbreak would be a gargantuan task. At best, it might be only a temporary solution, as we don’t know how many more cities will diagnose coronavirus infections in the coming weeks. King County, Washington has experienced a significant number of confirmed coronavirus infections, and as of March 4, advised, “If you can feasibly avoid bringing large groups of people together, consider postponing events and gatherings.” California has declared a state of emergency, putting the March 26 Dodgers, Athletics, and Padres home openers at risk. The Mariners’ home opener is also scheduled for that day.

An MLB spokesperson noted that the league has communicated with other professional baseball leagues experienced with a coronavirus outbreak. Perhaps for the regular season, MLB should look to the examples set forth by NPB and the KBO’s preseasons: Continue to play games as scheduled, but exclude spectators. This wouldn’t be entirely unprecedented in the majors. This brings us to an awkward question: Does attendance have any meaningful relevance to the interests of MLB organizations? A game with no attendees obviously means a decrease in ticket revenue and concession sales, but a game with no attendance comes with the added benefit of eliminating many off-field labor costs, while still generating revenue from the game’s broadcast. 

Baseball is a business, and owners may be reluctant to make potentially gutting cuts to their revenue stream in the interest of public safety. However, given the potential pandemic, MLB should remember its obligations to the community. As Dr. Linas notes, “The toughest question is, how much risk is MLB willing to take? While the disease is non-fatal for the majority of those infected, is it worth it to keep the game going and possibly spread an infectious disease?” As community transmission is being observed in more and more cities, it is increasingly apparent that self-isolation and social distancing may be necessary to protect the more vulnerable. It’s possible the CDC and local public health departments will eventually recommend against large gatherings like baseball games, but even if they don’t prohibit them outright, a fan-friendly ticket-exchange policy would be a welcome show of good faith from MLB.

While we as fans have little say in the amount of risk MLB takes, we do have control over how much we as individuals are willing to take or to impose on others. If you’re sick and have reason to believe your illness may be related to the novel coronavirus, please think of your fellow fans and consider staying home. The good news is, the vast majority of patients will recover from a SARS-CoV-2 infection. Unless you are elderly, immunocompromised, or afflicted with other respiratory conditions, you will most likely be fine if you take appropriate precautionary measures. Practice good personal hygiene, and get into the habit of sneezing into your elbow. Washing your hands, using hand sanitizer containing at least 60 percent alcohol, and disinfecting surfaces will go a long way, whether you’re a baseball player or a fan. If you haven’t already received a flu vaccination this year, please do so; while the flu shot won’t have any effect on a coronavirus, fewer flu cases will ease the burden on medical personnel in the event of a COVID-19 outbreak.

All of these are actions that you can take and should be part of your routine, not just when the threat of a pandemic looms over the horizon. The beauty of Opening Day lies in the shared pleasure of welcoming back the sport we love. It’s an event that brings together fans of all stripes, united in joy as we celebrate the beginning of a new season. That same camaraderie should remind us to be mindful of others in our communities, baseball or otherwise.

Stephanie Springer is an organic chemist turned patent analyst.


Centers for Disease Control and Prevention, “Coronavirus Disease 2019”, 

Zeynep Tufekci, “Preparing for Coronavirus to Strike the U.S.”, Scientific American, February 27, 2020

James Hamblin, “You’re Likely to Get the Coronavirus”, The Atlantic, February 24, 2020 

Jeff Passan, “MLB has no plans yet to cancel or postpone games over coronavirus”, ESPN, March 3, 2020

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frank noto
This is one of the most informative articles on COVID-19 that I have encountered. Great job!
John Johnston
“ Unless you are elderly, immunocompromised, or afflicted with other respiratory conditions”

I’m all three. Expect not to see me again here after the coronavirus goes national.
Steven Goldman
For you and everyone out there (and heck, us too), we very much hope that that is not the case. Take care, John.
John Johnston
Thank you, Steven.
Adam lang
It's not quite clear who gets affected. The medical professionals in China were young enough. And the US doesn't have a lot of cases yet because it appears that the CDC isn't testing to keep the numbers low (or don't have enough tests). I would guess we will have empty stadium games.
Evan Carter
Until the players start getting infected. Then the season will be brought to a crashing halt.