No, the Science on Masks (and Neck Gaiters) Hasn’t Changed Again

This post contains a video, which you can also view here. To support more videos like this, head to patreon.com/rebecca!

Transcript:

Ah, the exhausting march of science in the time of COVID. Science is always an ongoing process of whittling away untruths until you eventually arrive at something that can mostly be called “probably true.” It can be frustrating for the general public to see it happen: like, when I was a kid, Pluto was a planet and brontosaurus was a dinosaur. Now, Pluto is a dwarf planet and brontosaurus…well honestly I just wasted a good hour reading up on the history of the brontosaurus and I’m still kind of confused. Scientists thought it was a brontosaurus but then in 1903 they found that it was just an apatosaurus but then in 2015 it turned out that there really was a different thing called a brontosaurus so I guess there’s a brontosaurus again now. So it’s the same as it was when I was a kid but a lot happened since. Or I should say it’s not the same as when I was a kid because apparently I was a kid during the time that brontosaurus wasn’t considered a real thing but I guess our science textbooks were really, really out of date. I’m still processing all this information, please be considerate during this difficult time.

As annoying as all that is, it’s even more upsetting when the science changes in real time as everyone watches, which of course is what’s been happening during this pandemic. Normally results need to be vetted, peer-reviewed, and published before the media picks it up and lets the general public know what it means, but with thousands of people dying every day, it’s important that the public know what to do as quickly as possible.

So, for I think the third time this pandemic, let’s talk about masks. Specifically, let’s talk about this Washington Post article and its many clones: “Wearing a neck gaiter may be worse than no mask at all, researchers find.”

Sigh.

As usual, here are the facts up front: that headline is not true. Necessarily. I mean, the impression it leaves you with is not true. Because here’s the thing — you probably see that headline and think, “Oh, researchers performed a rigorous peer-reviewed study that found that a neck gaiter is actually worse than no mask at all.” In fact, here’s a random Tweet I saw that interpreted it just like that: “Some masks are worse than no mask at all” says a comprehensive Duke University study on the efficacy of face coverings.”

Nope! In fact, there was no study on the efficacy of face coverings. This is actually about researchers who developed a potential test to determine the efficacy of face coverings. The “study” is simply them describing this mechanism they built, which they say could be a low-cost way for organizations to test their masks. It is not, in fact, an actual test of how masks can help or hurt our response to COVID-19.

In the actual paper, published in Science Advances, Duke scientists described their creation: a “straightforward” setup requiring “ubiquitous or easily acquired” hardware and software. They were trying to make a device that was inexpensive and could be built and operated by non-experts, so it involved a cell phone camera, a laser beam, a lens, and a box. They demonstrated how a person could put on a mask and speak into the box, and the camera would capture the laser beam bouncing off the droplets that are expelled into the air. An algorithm would then examine the images and determine how many droplets were expelled.

That’s it. That’s the paper. The purpose of this was simply to describe a potential measurement device, and not to actually measure the difference between various masks. But to show that the device actually could differentiate between various masks, the researchers had one person speak through each of 14 different masks, and then they had four different people speak through a handful of those masks. They take pains to point out in the article “In this application, we do not attempt a comprehensive survey of all possible mask designs or a systematic study of all use cases. We merely demonstrated our method on a variety of commonly available masks and mask alternatives with one speaker, and a subset of these masks were tested with four speakers.” And later, “Again, we want to note that the mask tests performed here (one speaker for all masks and four speakers for selected masks) should serve only as a demonstration” and that results may vary based on the speaker, how the mask is worn, how it fits, what the speaker is saying, and other attributes.

So why did the Washington Post, and many other outlets, run with “neck gaiters are worse than nothing” headline? Well, in their quick test, the researchers did find that neck gaiters produced more droplets than a control with no mask, and that was surprising. They believe this is because the fabric breaks up a few large droplets into many smaller droplets, and that can be an issue because smaller droplets tend to hang in the air longer. 

However! They did not do any follow up tests on this, because the point of the paper was to create the device, not investigate various masks. So you have one to five subjects speaking through one mask one time each. That’s it. N=5 is not a study. It’s an interesting hypothesis that should be tested more.

And even if the results do hold up, if neck gaiters do increase the number of droplets, more research would have to be done to see if that’s a bad thing. Sure, more droplets seems like a bigger problem but it’s actually more tiny droplets and fewer big droplets. Small droplets hang in the air longer but do they spread the virus as easily as large droplets? And is the difference in how long they are airborne significant? And if you’re outside, does it even matter?

All of that is something for future researchers.

You know what that means: back to my usual advice, courtesy of Douglas Adams. Don’t panic. If all you have is a neck gaiter (or a handkerchief, which they found to be similar), you can keep using it. If you’re high risk or spending time indoors with other people for some reason, go with the things we already suspected worked best: N-95 masks, surgical masks, and layered homemade cotton masks. And if you can help it, stay home, stay away from crowds, and stay as sane as you can.