This respiratory illness season, face masks are back in fashion. U.S. public health officials are encouraging people to take precautions against rising cases of COVID, influenza, respiratory syncytial virus (RSV), pneumonia, and the like. Mandy Cohen, director of the Centers for Disease Control and Prevention, recently issued a video advising people to get updated vaccinations and stay home when sick—and, of course, wear a mask—especially as people travel and gather for the holidays.

Properly wearing face masks is one of the most effective ways to lower risk of COVID infection, and it also can help protect against the other respiratory bugs currently circulating. According to CDC surveillance networks, 172,490 adults and children visited the emergency room for COVID, influenza and RSV during the week of December 10. And as this percentage has increased, mask use also appears to have gone up in some communities and settings, says Audrey Dorélien, a public health demographer and associate professor at the University of Minnesota.

“I do think now people are wearing masks when they think the risks are increasing,” she says, but she doubts this to be ubiquitous across the U.S. A not-yet-peer-reviewed study co-authored by Dorélien that uses survey data from 2020 has revealed that even when there were mask mandates, only about half of people in Minnesota masked around nonhousehold members. The decision to mask or not is influenced by innumerable factors, from culture to politics to the social norms of a community, explains Emily Mendenhall, a Georgetown University medical anthropologist, who authored the book Unmasked, about antimasking behavior in her Iowa hometown.

“I think that we all have different calculated risks, and those risks are based on our own personal experience and perceived vulnerability,” she says.

Scientific American spoke with Dorélien and Mendenhall about the current state of masking behavior and what to consider about protecting yourself and loved ones from getting sick this holiday season.

[Edited transcripts of the interviews follow.]

What are the reasons people continue to mask? Is it just for COVID or for any respiratory disease?

DORÉLIEN: COVID is new and emerging, but in one sense, masking shouldn’t just be necessary for COVID. We shouldn’t treat [masking] so differently for other respiratory diseases. So if RSV or flu is very high in your area, the messaging might be, “Hey, you may consider masking.” I personally wear a mask when I think I’m in a more high-risk situation—not only out of concern for COVID but just my concern for respiratory illnesses in general. When I’m on airplane rides, I tend to always wear a mask. I might take off my mask briefly in the middle of the flight when the airplane filtration system is working at 100 percent. I make sure that I wear a mask when I’m with people at high risk, like at health care facilities.

MENDENHALL: We published a paper on the “sometimes masker” a couple years ago. What we found is that, especially in the first year of the pandemic, there were some people who would always mask. I was one of those people who would not go anywhere without masking. There were some people in the community where I grew up [in Okoboji, Iowa], who just absolutely would not mask, and that was more of a moral or political stance, in their perspective. For people who always masked, it was a moral or political stance as well.

Then the “sometimes maskers” is an interesting area, and the “sometimes masker” is the area that has grown. I think those people have used different moral decision-making around when they should mask. For example, if you’re going to be with someone vulnerable and you’ve tested [positive for COVID] or you don’t feel well, you might mask. Or any time you fly or go on a train, you mask. If you’re really exposed to people who you don’t know and you don’t know their risk profile—if you don’t know whether they’ve been feeling sick—then you mask. But then there’s other places where you don’t mask as much—when you’re with people who you know are testing or if you are just in and out of the grocery store.

People who work in high-risk jobs are also still masking. I think that people who are more vulnerable are really still masking. People with disabilities are still being incredibly, incredibly careful because they have to be. Even if the general population has kind of moved on, that doesn’t mean that people don’t make calculated decisions to mask.

The decision to mask has been deeply rooted in social and political pressures. How has this shifted over time?

MENDENHALL: It’s really culturally specific and community specific. In the U.S. it’s also very political. The politics have shifted tremendously, but there are some people who probably hold the exact same beliefs that they did at the beginning of the pandemic. Early on in the pandemic, you were shamed by some if you masked, and you were shamed by others if you didn’t mask, and I think [different people are now using shame]. I think people, especially on the far left, who are masking are definitely still using shame, but they deeply, deeply feel that everyone should still be masking. There are some people who are also quite angry when people say the pandemic is over.

DORÉLIEN: For our social contact survey data in Minnesota from fall 2020, I did not have information about people’s party affiliation—but I knew their zip code. What we found is that adults who lived in zip codes [in which the majority of people] voted for [President Joe] Biden were 24 percent more likely to wear a mask with nonhousehold members, compared with adults that were living in zip codes that voted for [Donald] Trump. I’ve been working with the University of California, Berkeley, on a big national contact survey. In that national survey, which was conducted from June 2020 to May 2021, we found that Republicans wore masks about half the time with their nonhousehold member contacts, while with Democrats it was closer to two thirds. [Editor’s Note: Dorélien’s findings on partisanship and masking are pending peer review.]

Do you think the U.S. will ever adopt routine masking in the winter like many Asian countries do? Has there been a shift among some Americans masking during peak respiratory illness season?

MENDENHALL: The U.S. is such a multi-ethnic, multi-culture context. I think there are some cultural norms in some regions of the country and not others where people will mask routinely. I think that some people never masked ever, and they never will. On the other hand, if we think about some Asian cultures, people have always masked, and they always will. This is framed by how others in your community think about ideas of protection, and in the U.S., it’s very political. I see people are masking in my community, which is a fairly liberal, elite community around Washington, D.C. Now when I go to my hometown in rural Iowa, there’s, like, no mask in sight. There’s no way people I grew up with are going to mask if they have a cold. And if you masked, you’d be looked at funny.

DORÉLIEN: Anecdotally, right before Thanksgiving, I started seeing a lot more people masking. Around the holidays, people are traveling, and they’re thinking, “It’s not worth getting sick before I have to go see Great-Grandma.” So I do think it’s going to be more common for a fraction of the population. But I’m not sure yet if there’s momentum to see masking at the levels that we see in Asian countries. I do think rates of masking in the U.S. are probably higher than they were prepandemic. Prepandemic, I think it would have been really odd to see someone mask, but I think now people understand the risks a little bit more. COVID is not gone, but the risks are a lot lower than they used to be. And I do think there will never be zero risk of anything—life has risk. So I think with masking, people may be a little turned off with the idea of “all the time.” I think people just want to know when to turn on this tool temporarily when the risk is high.

How does vaccination status influence masking behavior?

DORÉLIEN: Looking through some preliminary analyses of our [national] data from May 2021, we actually found out people who were vaccinated were also more likely to wear masks compared with nonvaccinated people. Vaccination is great and effective. So sometimes there’s a worry that if you’re vaccinated, then you might take more risks. But people who got the vaccine stated in the survey that they were more concerned and cautious during the pandemic. So even if they relaxed their mask-wearing or their protective behavior, they’re still masking at a higher rate than people who are not vaccinated.

How does behavior change if you’ve had a previous COVID infection?

MENDENHALL: I think that people make calculated risks based on their exposure and persistent symptoms from past COVID infections. When I had COVID earlier this year, I was sick for three months, and I really cannot experience that fatigue again. I wouldn’t say I had long COVID because I’ve now interviewed [many] people with long COVID [who had more severe symptoms], and that is like the worst thing ever. But I took a really long time to feel back to normal. That’s one of the reasons why I am masking: because I don’t want to get COVID again and get sicker. Now people who haven’t had a bad experience with COVID may not mask because they’re like, “Whatever—it’s like a small cold.” Their COVID experience is like a week off resting, and they’re not worried about it. They might have had COVID several times, and it hasn’t affected their life literally at all. [Editor’s Note: In some cases, people who have symptoms for three months may have long COVID. The CDC currently defines long COVID as prolonged symptoms that can be identified after four weeks from initial infection.]

Do you have any tips for people who want to join in on holiday social gatherings but also want to take precautions for their health?

DORÉLIEN: One thing that my research has shown me is that yes, we should promote mask wearing. But masking won’t be 100 percent; even at the height of the pandemic, it wasn’t 100 percent. In my [social contact survey] data set, it was a very small fraction of people who always wore masks with nonhousehold members. So to me, masking is just one tool—but what will be most effective are things that don’t rely on people’s individual behavior. I do think it’s really important to improve general air quality in public spaces and workplaces alike. When my kids’ day care removed masking requirements, it added extra air filters in the classroom.

COVID raised my whole awareness of air quality in general, and now I use portable CO₂ monitors, which also measure radon and PM_2.5 [tiny particulate matter with a diameter of 2.5 microns or smaller]. The CO₂ monitor measures what we exhale, our breath. When there are more people in the room, and especially if there’s no new air coming in, CO₂ increases. The higher the CO₂ level in the room, the higher the proportion of someone’s breath that you’re breathing in. So when we had people over for Thanksgiving, I checked the CO₂ and opened windows [when the levels got high]. There are some people I know that carry a portable one around, and if they see that the levels are very high, then they may choose to keep their mask on or not join. I think if there were more opportunities to place CO₂ monitors in rooms, then someone could see whether or not they’re comfortable in the space.

MENDENHALL: If you’re going to a small gathering, you can ask that everyone test [for COVID]. For example, we had a little holiday cookie exchange party last year, and we asked people to test before they came. There were like seven of my daughter’s [friends] who backed out because they were positive. I’m so glad I asked people to test. You can’t confirm that people tested, but you can suggest that people test.

I think you should just be cognizant of who you’re going to see. If you’ve been exposed, you’ve been to a lot of holiday parties, you’ve been flying, you’ve been at a big rager or a concert or something that puts you at risk of getting sick, first of all, get tested for COVID. But if you have a sniffle or a cough and you’re going to be around someone who’s elderly, living with a disability or biologically vulnerable in some way, absolutely mask, or at least get tested, and stay home if you can—and get a flu shot, RSV shot and COVID shot.