[Read: America is sliding into the long pandemic defeat]

Don’t Worry, It’s Not COVID

No one said anything to the man (at least to my knowledge). If someone had, though, I imagine that he might have replied with a now-familiar pandemic-times refrain: “Don’t worry! It’s not COVID!” Such assurances can be perfectly fine (polite, even), say, at the height of allergy season, when you want worried-looking company to know that you are not, in fact, showering them with deadly virus. But assurances only go so far. As my colleague Katherine J. Wu recently wrote, a negative COVID test, especially in the early days of symptomatic illness, is no guarantee that you’re not infected and contagious. And even setting that concern aside, still: Whatever it was that had that maskless man hacking away like a malfunctioning kitchen appliance, I didn’t want that either!

If you’re feeling sick, just because you don’t have COVID “does not mean that you rip your mask off and go get on an airplane next to other people—that’s rude,” Emily Landon, an infectious-disease physician at the University of Chicago, told me. “Maybe you’re ruining someone’s vacation … Maybe they’re going to see their mom in hospice. Let’s not ruin other people’s lives and plans.”

[Read: America is sliding into the long pandemic defeat]

Over the past two-plus years, the public has undergone a crash course in preventing the transmission of respiratory viruses. We have learned the importance of testing and masking and distancing and isolating and ventilating. These lessons, some better received than others, apply just as well to more familiar pathogens such as influenza and common-cold coronaviruses as to the novel one that has reshaped our lives. We understand better than ever how to be a good sick person. Now we’ll see whether anyone puts that knowledge to use.   

The first and most important rule of feeling sick is to stay home. This, says Ryan Langlois, an immunologist at the University of Minnesota, is at once “the easiest and the most difficult” directive. Easy because it’s so simple: Stay in your house! Do not leave! No technical expertise required. Difficult because actually following it entails major disruptions of daily life. For white-collar workers, the normalization of working from home has made this a good deal more convenient than it was (and has, one can only hope, dispelled once and for all the fiction that dragging yourself to work sick is an act of self-sacrificing fortitude; it’s not—it’s just plain inconsiderate). For much of the labor force, though, remote work isn’t an option, and more than a fifth of American workers don’t have paid sick leave. Among the country’s lowest earners—the people most likely to need it—only about a third do. (Every wealthy country in the world except the United States guarantees paid sick leave.)

[Read: The real reason Americans aren’t isolating]

The complicated part of isolating is knowing when to stop. No one-size-fits-all formula will spit out the right answer in every case, for every type of infection, Langlois told me. One person might be completely virus-free five days after symptom onset; another might still be highly contagious. Even for the most responsible among us, this ambiguity can make for some awkward calculus. Can you afford to miss that work meeting? How about family dinner? It would be a real pain to cancel those travel plans—but should you?

After a couple of years of COVID management, we at least in theory have better tools and practices for helping people manage these situations. Many of us have gotten into the habit of regularly testing and retesting ourselves for COVID, and now is no time to stop. But Seema Lakdawala, a flu-transmission expert at the University of Pittsburgh, envisions a world with universally accessible testing for a whole range of pathogens: influenza, RSV, adenovirus, rhinovirus, seasonal-cold-causing coronaviruses, and, of course, SARS-CoV-2. Sites at every street corner would offer patients not only a diagnosis but a prescription for the appropriate medication. People in rural areas could acquire at-home tests at drug stores or order them online. Someone who tested positive only for a seasonal coronavirus could undertake a more relaxed isolation (Langlois, for one, doesn’t think it’s practical to ask people to fully stay home for a common cold, though they should certainly still mask), while someone who tested positive for influenza, which kills tens of thousands of people most years, would know to take stricter precautions. Whatever the situation, you’d know you were in the clear when you tested negative for whatever you’d originally tested positive for.

For now, Lakdawala admits that a world of such universal, accessible testing remains a distant fantasy. She and the other experts I spoke with offered several more-practical pieces of guidance. Even if it gets awkward, it’s good practice to notify people you may have exposed to a pathogen, just as we’ve been encouraged to do with COVID. If you have a fever, keep to yourself as much as possible until at least 24 hours after it subsides. If you don’t have a fever, Landon told me, you should be clear to reenter society after your symptoms resolve. For a common cold, she said, that generally takes three to five days; for flu, five to seven. Certain symptoms can stick around for weeks after that, but as long as you’re not feeling disgusting, Landon said, you can responsibly venture out. (Call it the “ew” test.) Leaving isolation with a lingering cough is fine, Saskia Popescu, an epidemiologist at George Mason University, told me, “as long as it’s not that wet, nasty cough.” (If you’re really interested in the nitty-gritty, you can always consult the CDC’s 206-page door-stopper on isolation precautions, but Popescu does not recommend: “I wouldn’t subject anyone to that.”)

If you’re still symptomatic after the recommended isolation period, or if you must venture out before it’s over, whether on an essential errand or because your employer doesn’t grant sick leave, you should wear a high-quality mask. The same is true, Landon told me, of that ambiguous period when you feel a little off and are just starting to wonder whether you’re coming down with something: If you’re not sure, mask up. People tend to be quite contagious during that stage, and the worst thing that can happen is you take a minor superfluous precaution and wake up the next morning feeling fine. Yes, masks can be uncomfortable, and yes, it’s a tragedy that such a fundamental health intervention has been co-opted into the culture war, but they remain one of the most effective, least disruptive tools at our disposal for fighting all types of respiratory infections. An N95 or KN95 is best, but a surgical or cloth mask is better than nothing, Lakdawala said, especially because plenty of people can’t afford to continually replenish a stock of top-notch disposables. Health-care providers and employers, she suggested, could offer free masks, which would protect patients, workers, and those around them.

Like widespread testing, a continuous supply of free masks and universal paid sick leave are merely a distant vision. Congress is currently struggling to prop up our most basic public-health infrastructure during a pandemic, leaving Americans to figure out COVID for themselves. The same will likely apply to all the other familiar viruses we reacquaint ourselves with. Whether the more modest, behavioral changes we’ve adopted over the past two-plus years outlast the pandemic is anyone’s guess. In this era of perpetual flux, one constant has been the disconnect between what we know we ought to do and what we actually end up doing.

Better to know than not to, but personal experience hasn’t left me optimistic that knowledge will reliably translate into action. On the train, after a few minutes of fruitless waiting to see whether the man a few rows back would stop coughing, I gathered my bags and relocated to another car. At first, all was quiet. Then two people started to cough.