On Sunday night, New York Governor Andrew Cuomo announced that the city had its first case of coronavirus. The patient, a health care worker who just returned from Iran, lives in Manhattan. “She is a health care worker,” Cuomo tweeted, “she knew to take precautions & didn’t take public transportation.”

New York City is not alone. There are also confirmed coronavirus cases in Washington state and the San Francisco Bay Area. With this news comes a fear of being in public spaces and sharing close quarters with strangers, especially on public transportation.

Already, local news outlets in Seattle and San Francisco have run the obligatory “What [local transit agency] Is Doing About Coronavirus” articles. New York’s versions are sure to come. This follows the generally accepted wisdom that public transportation is a germ-infested petri dish of humanity that incubates novel diseases even during non-pandemics.

In fact, people think public transportation is the biggest incubator of pandemics. A 2005 survey of 3,436 people conducted in various European and Asian countries found about 75 percent of respondents would avoid public transportation during an outbreak. People from Hong Kong, Spain, Poland, Denmark, Great Britain, and the Netherlands said they viewed public transportation as the most risky place for infection. Only respondents from Guangdong, China and Singapore thought entertainment districts were riskier than public transit.

However, in the case of a global pandemic, it’s actually not clear how much public transportation, meaning the trains or buses within an urban area, contributes to a virus spreading. (To be clear, I’m not talking about intercity transportation like airplanes and, in some countries, high-speed rail, which is a whole other topic.) As a result, we're actually not sure whether avoiding public transit—or shutting it down altogether—is a good idea except in the most extreme cases.

To be clear, I am also not talking about if you’re experiencing symptoms of coronavirus. For people who think they might be getting sick or have recently visited a high-risk area, self-quarantine is a good idea as the health care worker in New York did.

But if that doesn’t apply to you, then you probably shouldn’t fear public transit, at least any more than any other public space.

First, it’s worth pointing out that public transit’s impact on the spread of epidemics is not particularly well understood, because it’s hard to isolate from other factors. One study from Nottingham, England tried to examine this issue by looking at the public transit usage of 138 patients who consulted with a doctor up to five days before their doctor visits. The study found the people who took public transit had an increased risk of an upper respiratory infection. However, the study was small and had a number of limitations, including the fact that all of the participants went to a doctor in a short period of time. It was also looking at a common seasonal illness for which some people develop immunity, not a novel virus like coronavirus.

The most relevant study, though, was a 2011 modeling of how a hypothetical influenza epidemic would spread throughout New York City, specifically focusing on the role the subway would play. The model found only four to five percent of transmissions would occur on the subway. Instead, most infections would occur within households (30 percent), at school (24.5 percent), and in other community settings (32.2 percent), such as entertainment districts, community meetings, bars, restaurants, etc. Ironically, these results are the exact opposite of the 2005 survey cited above where people believed home was safest and public transit was riskiest. This model’s findings suggest “interventions targeted at subway riders would be relatively ineffective in containing the epidemic.”

Therefore, riding public transportation in and of itself is probably not where people get sick. It is all the places riding transit enables them to go. If you use public transit, you’re likely using it to go to a big office building with one set of doors or elevators for hundreds or even thousands of people. You’re likely going to coffee shops and restaurants and standing on street corners huddled next to lots of other people.

Not only is public transportation probably not where people are actually getting sick, but avoiding it—or, in extreme cases, limiting service—has serious consequences in the health care community’s ability to respond to such pandemics. Health care workers often rely on public transportation to get to work, and have cited unreliable transportation as a major source of absenteeism during pandemics, which strains hospital resources when they need workers the most.

A 2009 survey of 2,864 health care workers found transportation concerns, along with safety and child care issues, were the main causes of absenteeism during a pandemic. Notably, even health care workers seem to fall into the trap of thinking public transit poses an inordinate infection risk, because when the survey asked if they’d be more likely to go to work if the hospital organized a private van service, many said yes. But only a small number of respondents said a transit pass would help.