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Scientists still can’t decide if face masks actually do anything

Published Apr 13th, 2020 1:00PM EDT
coronavirus mask
Image: narongpon chaibot/Shutterstock
  • Science can’t decide how effective surgical masks and homemade alternatives are at preventing the spread of coronavirus.
  • The CDC suggests making your own masks at home, but researchers can’t say if they’ll do any good.
  • Masks are more effective when worn by sick people than healthy people, the data suggests.
  • Visit BGR’s homepage for more stories.

It’s now been months since the coronavirus outbreak reached the point of a pandemic, and we somehow still don’t have a clear answer on how effective face masks are at preventing its spread. As LiveScience reports, a new batch of studies into the efficacy of various types of masks does little to settle the debate.

It was just days after the novel coronavirus hit the shores of the United States that health experts were falling all over themselves to make declarations about the use of protective face masks. Initially, experts asked that everyday people avoid buying masks meant for use by doctors and healthcare professionals since those are the people who need them the most.

That made perfect sense, especially since the N95 masks that are the most useful in halting the virus were in such short supply. Health experts urged the public to avoid using masks entirely, as long as they were healthy, and that only people who had the virus should consider wearing one to prevent spreading it widely to others.

Most of the public seemed content with that advice, at least for a little while. Then the CDC updated its stance on face masks, advising the use of cloth masks — similar to surgical masks — and even went so far as to produce a guide on how to make masks yourself at home.

But do cloth masks (or even surgical masks) really do anything? There’s a lot of confusion here, and the fact that so many purported health experts initially said to avoid wearing masks hasn’t helped matters. Unfortunately, it seems even science can’t make up its mind.

A pair of new studies — one published in Nature Medicine, and the other in the Annals of Internal Medicine — attempted to tackle the question of face mask efficacy and reached wildly different results.

The study published in Annals of Internal Medicine was incredibly small in scale and involved just four confirmed COVID-19 patients. For the study, each patient coughed into a petri dish from a distance of around 8 inches. Each participant coughed once without a mask, once with a surgical mask, and once with a cloth mask like you might make at home.

The results showed that neither of the masks significantly changed the amount of virus that made it onto the petri dish. This, it would seem, suggests that the masks are pointless… right? Not so fast.

The fact that the study was so limited in scale and that the researchers didn’t bother to check if the results were different at greater distances means that the data, while possibly accurate, is too meager to mean much of anything. It could be that masks don’t stop droplets containing the virus from reaching a distance of 8 inches, but they still could prevent it from reaching greater distances, which would mean they’re still at least somewhat useful.

The second study, published in Nature Medicine, holds a bit more water. It involved over 400 volunteers who were told to exhale into a filter that captures everything coming from a person’s mouth. The scientists tallied the various viruses they found, including rhinoviruses that cause colds, influenza, and coronaviruses similar to, but not exactly the same as the one that causes COVID-19.

The researchers then tested surgical masks to see how well they controlled the viruses being exhaled by the participants. The results showed that surgical masks do catch at least some of the influenza virus in the form of droplets coming from a person’s mouth, but it did not prevent the passage of aerosols of the virus. For rhinovirus, the masks didn’t reduce transmission in either droplet or aerosol form, but things were different for the coronaviruses.

The surgical masks seemed to mitigate the transmission of the coronaviruses in both droplets and aerosols. None of the patients tested had the novel coronavirus, but the researchers believe that the similarities in the viruses would cause the COVID-19 variant to produce similar results.

Still, this is far from a ringing endorsement of using surgical masks or cloth masks as a daily habit. There’s still no clear and obvious evidence that wearing one of these masks as a healthy person prevents you from getting the virus, especially since air will tend to flow around the edges of these loose-fitting masks rather than through them.

Right now, it seems the best thing we can all do is just avoid each other and large gatherings for as long as possible. The social distancing measures we’re taking are indeed working, and as the curve flattens and progress is made on a vaccine, we’re better off continuing our “new” way of life for a while longer rather than cutting up our t-shirts to make masks and heading to the mall.