Paul Sax is a Harvard infectious diseases specialist who likes to play poker. Every few weeks, he plays with friends in Boston. Recently, when it was Sax’s turn to host, one of the game’s regulars came down with a cold. The player, Sax told me, tested negative for COVID—but offered to stay home anyway.
Sax took him up on it. “Why go through the hassle of getting a cold?” he told me, offering some practical advice: “If you’re going to the house of an infectious-disease doctor, don’t come with a cold.”
This fall, Americans have been sick. A “tripledemic” of COVID, the flu, and RSV is under way. COVID and flu hospitalizations are on the rise, while RSV cases may, thankfully, be peaking. And those are just three of the respiratory viruses currently circulating: Don’t forget about the rhinoviruses and coronaviruses that cause the common cold. Parents have been missing work in record numbers to take care of their children.
But of course, people want to hang—want to be with friends and family, especially after two years of holiday disruptions. In some ways, the question people face is the same one they have faced the whole pandemic: How can we spend time together safely? But the question is also different now, with so many more minor viruses circulating—people might be willing to take a chance on a runny nose or a sore throat. So should you stay home? How sick do you need to be to sit out the holidays a third year in a row?
For starters, pretty much everyone agrees that one symptom is an absolute no-go: fever. A temperature equals stay home, for at least 24 hours. (And no cheating with ibuprofen: You should be fever-free without pain meds.) Two other “red flag” symptoms some experts mentioned are vomiting and diarrhea.
Beyond that, it gets a bit trickier. One reason is that some of these viruses can feel the same, which means you might have to treat cold symptoms as if they could be a more severe illness. For example, RSV “feels just like a cold for everybody except those under 2 years old—particularly under six months—and those over 65,” Peter Chin-Hong, a professor of medicine at UC San Francisco, explained to me, speaking in general terms.
Tests can offer clarity here—Yep, it’s the flu, not a cold—but not all tests are available over the counter. Which is a bummer, because, besides being a useful diagnostic tool, tests may give us a sense of a person’s contagiousness. At-home COVID rapid tests are thought to be a good measure of infectiousness; some experts recommend that you can leave isolation by testing out. That’s not an option for the flu, RSV, or a cold.
I asked Jay Varma, a professor at Weill Cornell Medical College who formerly worked for the CDC, if there are any symptoms a person just doesn’t want to mess with in terms of getting other people sick. He told me that if I had asked him about this pre-pandemic, he would’ve offered that standard guidance about being fever-free for 24 hours and making sure your symptoms are resolving. But mass repeated COVID testing taught us that symptoms and their severity aren’t linked as closely as we thought to whether you can spread the coronavirus. “Even having no symptoms at all, you could be more infectious than somebody with symptoms,” he said. “The challenge is that similar types of large-scale analysis have not previously been done before for RSV or influenza.”
Without at-home tests or better research for other viruses, people can use the length of the infection to estimate whether they are still spreading the virus, though that gets into a gray area. In general, experts told me that the initial phase—the first week in particular—is the most important for staying home, because that’s when you’re likely the most contagious. Katelyn Jetelina, who writes the newsletter Your Local Epidemiologist, told me that, as a parent, she keeps track of her children’s illnesses, marking day one of symptoms. With the flu and RSV, people can be contagious for as many as seven or eight days.
But that’s not a perfect rule: For example, in the case of RSV, some infants and people with weakened immune systems can spread the virus for as long as four weeks, she said. “Your individual health status is going to have an impact on how long you’re contagious,” Donald Milton of the University of Maryland told me, citing flu data suggesting that children and people with obesity stay contagious for longer. That’s not everyone, but even so, many people underestimate how long they will be sick with just a run-of-the-mill virus. “On average, a bad cold lasts 10 to 14 days,” Sax said. “And yet people seem to have almost amnesia about that fact.”
For that reason, Milton draws a hard line: “Basically, you need to ask people, ‘If you’ve got cold or flu symptoms, please stay home.’” If people who are recovering from a virus do come to the gathering, they should wear a mask, he said.
One symptom that makes things difficult is a lingering cough. Once a person is past the initial phase of being sick, some coughs will continue to be caused by the virus, while others will be from irritation to the airways—almost asthma-like. And sorting out which is which is impossible, Sax explained. Either way, “you’re not going to be very popular at a party if you're coughing a lot,” he said, laughing. Tara Kirk Sell of the Johns Hopkins Center for Health Security told me she would personally not be concerned about a cough after two weeks but suggested that a person could reach out to their primary-care physician for advice.
Beyond considering the length of time since symptoms started, people can also take into account whom they plan to see over the holidays. The youngest and the oldest Americans are particularly at risk in this tripledemic. If you’re visiting a new baby or an elderly relative, that might be time for extra caution.
The COVID tool kit we’ve all grown so familiar with—wearing masks, running HEPA filters, opening a door or window for ventilation—can also be used to mitigate risk. On top of that, people can take precautionary measures, like staying up-to-date on flu and COVID vaccines. They can also remember to wash their hands. (Even though COVID is accepted to be transmitted by aerosols—and the flu at least partially so—experts are still debating whether RSV and rhinovirus are, Milton told me.) Scrubbing your hands clean can help protect you from not-respiratory-but-still-absolutely-miserable viruses, such as norovirus.
Perhaps above all, be considerate. Sax said that, in general, people were probably too lax about exposing others to their sickness pre-pandemic. “The kinder thing to do, the more generous thing to do, is to err on the side of just being cautious.” Families of young kids—where it can feel like someone is always sick—may find this winter frustrating. “It’s really, really challenging to navigate as a parent,” Jetelina said.
Sell recommended using the golden rule, and considering whether you would want someone as sick as you sitting next to you. “Just because it’s not going to kill them doesn’t mean you’re like, ‘Ahhh, here you go. Here’s your Christmas present,’” Sell told me. “That’s not a gift anyone wants.”