Cloth Masks May Look Better, But They Don’t Work Better
Cloth Masks May Look Better, But They Don’t Work Better
It was nice to see everybody, Democrats and Republicans alike, wearing face masks at President Joe Biden’s inauguration last week. Former President Donald Trump’s refusal not only to wear masks but also to countenance his aides doing so was one of the silliest and most self-defeating aspects of his literally self-defeating Covid-19 response, although it did seem to provide some more evidence that masks work, given how many people at the White House ended up getting the disease.
It was a little unsettling, though, to see how flimsy some of the masks were that covered familiar (and aging) faces last Wednesday. Former President Bill Clinton, who is 74, had a thin, seemingly-too-small cloth mask that kept slipping below his nose. Chief Justice John Roberts, 65, had similar if less extreme nose-coverage problems, and a similarly flimsy mask. Among those sitting close to the lectern, cloth masks — albeit mostly ones that covered noses a lot better than Clinton’s and Roberts’s did — were the norm, with Vice President Kamala Harris’s stepson Cole Emhoff standing out with his white N95 respirator with a big “3M” stamped on the front.
This was outdoors, the parties were seated quite far from one another, all of those on hand had recently tested negative for Covid-19, and most had probably gotten at least their first dose of vaccine already. It’s also understandable that people expecting to be on national television for an extended period of time preferred to wear masks that matched their suits or dresses rather than standard-issue light blue or white disposable ones. Also, as one got farther away from the center aisle the light blue and white face disposable masks became more common. So I’m not too worried about the inauguration turning out to be a super-spreader event. It just seemed like a bit of a lost opportunity to spread the message that cloth masks are a second-best option in thwarting the spread of Covid-19.
This message was less appropriate early in the spread of Covid-19 because disposable masks made of non-woven plastic fabrics and designed to thwart infectious disease were in short supply, and just getting enough for medical workers a challenge. China, usually by far the world’s biggest exporter of protective masks, with Germany and the US coming in second and third, was at first hoarding its production for its own pandemic response. Cloth masks, even those crafted at home out of old shirts and pillowcases (which is what I made for my family with a newly acquired sewing machine), were better than nothing and in many cases the only thing available.
Now things are different. After getting its Covid-19 epidemic under control, China quickly went back to exporting and other countries ramped up production, too. In the US, Ford Motor Co. is one of the new mask makers, supplying 15,000 surgical masks with “59th Inaugural Ceremonies” printed on the front for last week’s event, although Senate Majority Leader Chuck Schumer and House Minority Leader Kevin McCarthy were the only prominent figures I saw wearing them. Medical masks are widely available in stores. But for the most part they’re not what one sees covering mouths and noses in America’s supermarkets and buses and on urban sidewalks. “Cloth masks, especially homemade ones, were supposed to be a stopgap measure,” sociologist Zeynep Tufekci and tech entrepreneur Jeremy Howard, two of the earliest US advocates for widespread mask-wearing, wrote in the Atlantic recently. “Why are so many of us still wearing them?”
Howard is the lead author and Tufekci a co-author of an influential and extremely informative “evidence review on face masks against Covid-19” that has been making the rounds since April and was published this month in the Proceedings of the National Academy of Sciences. The paper concludes that cloth masks may be similarly effective to disposable ones in reducing the chances that a mask wearer with Covid-19 will infect others, because they catch most of the virus-laden droplets that wearers expel when they cough or sneeze or talk. But when virus-laden droplets do make it out into the air, and — as is especially wont to happen in cold, dry winter weather — most of the moisture evaporates, leaving “aerosolized” particles that can float around for hours, disposable medical masks seem to do a better job than cloth ones of keeping them out.
The single-biggest piece of evidence for this comes from one of the rare randomized controlled trials of cloth-mask use, which was conducted in 2011 and published in the British Medical Association journal BMJ Open in 2015. One group of Vietnamese hospital workers was supplied with two disposable masks daily and another with five cotton masks that they were supposed to wash with soap and water and reuse. At the end of the four-week study period, cloth-mask wearers were 13 times more likely to have come down with influenza-like illnesses than the disposable-mask wearers. The cloth-mask wearers also got sick at more than three times the rate of those in the control group who received no instructions at all, a result cited by mask skeptics as evidence that cloth masks are worse than nothing. But because the institutional review board that oversaw the study determined that it would be unethical to ask any hospital workers not to wear masks and mask-wearing was already the norm in the hospitals studied, the members of the control group almost all wore either disposable masks or cloth ones.
Ever since reading that study last spring, I’ve been trying to follow a regime — made much easier by the growing assortment of disposable masks available at my local hardware store — of picking from the family stash of homemade and cloth masks when I’m about to engage in outdoor activities such as walking the dog or going to the farmer’s market, but putting on a disposable mask if I’m going to be spending much time indoors or in public transportation.
My disposable mask of choice is what in medical-supply parlance is known as a procedure mask, a thin covering with loops around the ears and wire at the top to fit snugly around the bridge of the nose. A similar mask with loops or ties that go around the head for a snugger fit and more comfort if you’re going to leave the thing on for hours is what technically constitutes a surgical mask, although that term is often used in popular discourse and even US Food and Drug Administration guidance to describe both kinds. A respirator is a usually thicker and stiffer mask that creates a tight seal around the face and is certified under names such as N95 in the US and FFP-2 in Europe as keeping out 95% (N95) or 94% (FFP-2) of particles 0.3 microns and larger. In non-pandemic times, respirators are widely used in non-medical workplaces where there’s lots of particulate matter floating around, not to mention Chinese cities in the middle of pollution alerts, as well as medical settings.
The SARS-CoV-2 virus that causes Covid-19 is only around 0.1 micron in size, but it virtually never travels alone, instead attaching itself to bits of saliva and other matter, so a well-fitted N95 mask should generally be effective in keeping it out. My reading of the evidence assembled in the paper by Howard et al. and other studies, though, is that surgical masks are almost equally effective in doing this. Also, while non-medical respirators with valves to make exhaling easier protect their users, they may be worse than useless in preventing infected wearers from spreading the disease.
Cloth masks too have been shown to be effective at stopping small particles if they’re composed of multiple layers, especially if those layers are made with different fabrics. It may be that cloth’s underperformance in the Vietnamese study cited above had as much to do with reuse and inadequate washing as with the intrinsic properties of the masks. Still, thin cloth masks of the sort that former President Clinton and Chief Justice Roberts were wearing at the inauguration are highly unlikely to provide as much protection as a surgical mask, and in general it’s just harder to be confident of the protective characteristics of cloth masks.
On the whole, then, it seems like disposable surgical and procedure masks are more likely to be effective in bringing down infection rates and fending off threats from new coronavirus strains than cloth ones, and more practical for most purposes than respirators. They’re cheap, light, comfortable-ish and easy to talk through — one maddening phenomenon of the past year has been people removing their masks in public to talk on the phone, which cancels out most of the mask’s effectiveness in keeping the wearers from spreading infection.
As has so often been the case over the past year, German Chancellor Angela Merkel is ahead of the curve on this, announcing last week that cloth masks will no longer be enough to shop indoors or ride on public transportation in Germany, with surgical masks or respirators required. I doubt that’s the right approach for the US, where just getting people to obey existing mask rules has been challenging enough. But signaling that disposable surgical masks are more effective than cloth ones — by changing official guidance and simply by wearing disposable surgical masks in public instead of cloth ones — ought to be a priority for the new leaders of the virus-fighting effort in the Biden administration. Removing shoddily made surgical masks from the market ought to be another one, Tufekci and Howard argue in their Atlantic article. Doing more to promote mask production may be a good idea, too, although shortages really don’t seem to be that big an issue now.
Yes, cloth masks are better-looking and often more comfortable than surgical masks, and probably more environmentally responsible. But the goal here is to make wearing masks unnecessary, and more widespread use of surgical masks seems like it will get us there sooner.