There's a lot of misinformation circulating about the effectiveness of neck gaiters as coronavirus protection. The truth is that the now-infamous Duke University study published in Science Advances was not conclusive, and it wasn't designed to be. Worse yet, the study did not attempt reproducibility beyond testing on just one participant and tested 14 face coverings, many of which cannot be reproduced in an independent study.
So don't throw away your neck gaiters just yet — they're a great line of defense against COVID-19, especially when you fold the neck gaiter for use as a double-layered mask. Monica Gandhi, a specialist of infectious disease at the University of California, San Francisco, echoed this sentiment. She says, "The headline that neck gaiters can be worse is totally inaccurate... It can turn people off of mask-wearing, which we know can protect both the individual wearing the mask and those around them."
We've already written about more recent research from Virginia Tech and the University of Georgia that disproved the Duke University findings. You can find that post here. But we wanted to take a moment to cover four more points that debunk the conclusions the mainstream media drew from the Duke University study. Let's dive in.
#1: The Study's Basis
In short, the study didn't test which type of mask is best; it tested how to test masks, which is a completely different research investigation. We already know that masks are scientifically-backed as a critical tool in preventing COVID-19 infection for the mask wearer, and because medical-grade masks are still hard to come by, many people have been using home-made multi-ply masks or neck gaiters to get the job done. Overall, there hasn't been a lot of research done about the effectiveness of makeshift masks in comparison to medical-grade masks.
The Duke University study, which many publications like Scientific American are lauding as 'bogus', was led by Martin Fischer, a chemist at the university. Fischer's team wanted to develop an easy and cheap method for labs to test the effectiveness of masks. In the study, they asked a masked participant to simply talk into a wide laser beam. When droplets were exhaled between words, they would show up as neon green splatters in the laser beam, and the number of droplets was subsequently counted using cell phone footage. 14 masks were rotated on the same person, and although some masks were tested on four people, this type of inconsistency isn't in line with a well-planned scientific study. The team analyzed the differences in droplet count over 10 trials.
In the above photo, #11 is the sole neck gaiter tested, while #14 is an N95 mask and #1 is a three-ply medical mask. All other masks are makeshift or homemade masks. The major issue comes from the calculation of droplet transmission and supporting conclusions that arose from the research. The researchers set a baseline mask-less transmission at 100% and calculated the fraction of droplet transmission from all 14 masks. An N95 mask had a transmission rate of less than 0.1%, while the neck gaiter transmitted 110%. The authors mention that the extra 10% might be because of the fabric of the neck gaiter's material creating smaller droplets from larger droplets.
Although the authors described their study as "proof-of-concept" research, the media started saying that neck gaiters may be worse than wearing nothing. When this happened, Fischer himself tried to set the record straight with the following statement and a press conference:
"Our intent was for this technology to get out there so companies and organizations can test their own masks,” explained Dr. Martin Fischer, a Duke University Chemistry associate research professor and co-author of the now infamous study. “Our intent was not to say this mask doesn’t work or never use neck gaiters. This was not the main part of the paper... It was not a systematic study of masks... Seeing the media somewhat misquote and misinterpret the data was a big downer."
#2: Testing Talking
Talking is one method to transmit the virus, but sneezing and coughing transmit the virus at a much higher velocity. Additionally, neck gaiters are popular with runners and those who exercise outdoors. It might be more apt to test neck gaiters for how well they block viral transmission with heavy breathing, rather than sitting and talking. Charles Haas is an environmental engineer at Drexel University, and he adds, "There are so many different sources of variability that influence how well a mask works. Without addressing those, making conclusions that differences are due to the type of mask is really a stretch."
#3: Inconsistent Amounts of Wearers
Because all of the masks were tested with one wearer, the sample size of the research is one. That's not enough data to evaluate scientifically or statistically. The researchers made the major mistake of not testing the masks on a variety of wearers. Haas says, "At an absolute minimum you’d need to test six to 10 different subjects, and six to 10 samples of the same kind of mask."
Masks fit differently on various face sizes and shapes, which can affect the effectiveness of the mask itself. The number of droplets produced by talking also differs from person to person. For those masks that were worn by four subjects, the researchers found that some people produced as much as five times more droplets than other subjects.
The study also neglected to mention the fabric composition of the neck gaiter as well as how it was constructed. This is important information because neck gaiters are sold with a variety of thicknesses and materials and can be folded into two-ply masks to increase their effectiveness. Within the paper, the authors wore that the study "should serve only as a demonstration. Inter-subject variations are to be expected, for example, due to differences in physiology, mask fit, head position, speech pattern and such."
#4: Calculating Droplets
According to Gandhi, measuring droplets makes sense, but the calculation isn't a true reflection of how much a mask can prevent droplet transmission, either to or from the wearer. The environment is also important when studying viral transmission as indoor environments have been shown to be riskier than outdoor areas.
However, she says, the researchers did not convince her that the study they implemented actually or accurately simulates "how people are actually around each other." Gandhi says that even if some masks weren't as good as others, they'd still be effective in slowing the spread of the virus.
The Bottom Line: Don't Ditch Your Neck Gaiter
Haas says that, unfortunately, "the results of this study have been misinterpreted beyond what the authors intended." Although there's still a lot to study and uncover about the effectiveness of masks, the modes of transmission, and infectiousness, Gandhi points to early research about COVID-19, which recommends "cloth face masks, and that includes properly worn neck gaiters, [to] filter out the majority of viral particles and provide some protection for an individual."
Keep your neck gaiter around because it's still effective in slowing the spread of the virus, and they are better than wearing nothing, despite what the Duke University study's conclusions are.
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