They’re also concentrated in the service industry or gig economy, in which workers have contact, directly or indirectly, with large numbers of people. These are the workers who are stocking the shelves of America’s stores, preparing and serving food in its restaurants, driving its Ubers, and manning its checkout counters. Their jobs tend to fall outside the bounds of paid-leave laws, even in states or cities that have them. Gershon emphasizes that having what feels like a head cold or mild flu—which COVID-19 will feel like to most healthy people—often isn’t considered a good reason to miss a shift by those who hold these workers’ livelihood in their hands.

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Even if a person in one of these jobs is severely ill—coughing, sneezing, blowing her nose, and propelling droplets of virus-containing bodily fluids into the air and onto the surfaces around her—asking for time off means missing an hourly wage that might be necessary to pay rent or buy groceries. And even asking can be a risk in jobs with few labor protections, because in many states, there’s nothing to stop a company from firing you for being too much trouble. So workers with no good options end up going into work, interacting with customers, swiping the debit cards that go back into their wallets, making the sandwiches they eat for lunch, unpacking the boxes of cereal they take home for their kids, or driving them home from happy hour.

Even for people who have paid sick leave, Gershon noted, the choices are often only marginally better; seven days of sick leave is the American average, but many people get as few as three or four. “Many are hesitant to use [sick days] for something they think is minor just in case they need the days later for something serious,” she wrote. “Parents or other caregivers are also hesitant to use them because their loved ones might need them to stay home and care for them if they become ill.”

For workers with ample sick leave, getting it approved may still be difficult. America’s office culture often rewards those who appear to go above and beyond, even if that requires coughing on an endless stream of people. Some managers believe leadership means forcing their employees into the office at all costs, or at least making it clear that taking a sick day or working from home will be met with suspicion or contempt. In other places, employees bring their bug to work of their own volition, brown-nosing at the expense of their co-workers’ health.

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Either way, the result is the same, especially in businesses that serve the public or offices with open plans and lots of communal spaces, which combine to form the majority of American workplaces. Even if your server at dinner isn’t sick, she might share a touch-screen workstation with a server who is. Everyone on your side of the office might be hale and healthy, but you might use a tiny phone booth to take a call right after someone whose throat is starting to feel a little sore. “Doorknobs, coffee makers, toilets, common-use refrigerators, sinks, phones, keyboards [can all] be a source of transmission if contaminated with the agent,” Gershon wrote. She advised that workers stay at least three to six feet away from anyone coughing or sneezing, but in office layouts that put desks directly next to one another with no partition in between—often to save money by giving workers less personal space—that can be impossible. No one knows how long COVID-19 can live on a dry surface, but in the case of SARS, another novel coronavirus, Gershon said it was found to survive for up to a week on inanimate objects.