To wear or not to wear a facemask

28 April 2020

Interview with 

Julii Brainard, University of East Anglia

FACEMASK

A woman wearing a blue facemask.

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“To Wear, Or Not Wear” THAT is the question. A face mask that is. Have you got one? Have you been using one when you’ve been out shopping? Have you been cutting up old t-shirts to make your own? Or are you a nurse or doctor worried that supplies are going to run out if everybody leaps on to the face mask bandwagon? It’s a tough call and it’s perhaps an understatement to say that the advice on whether we should all wear facemasks has been a little confusing. In some countries, mask-wearing is compulsory; in others it’s not. So let’s try and cut through to the scientific evidence. A team at the University of East Anglia have gone through all the research we have for airborne infections like coronaviruses. Basically, they’ve found that there is a protective effect, but, it’s small and, like all things coronavirus, the science isn’t straightforward and it depends on the context. Adam’s been speaking to Julii Brainard, one of the team behind the study...

Julii - The methods we used is something called a systematic review. And you look at all the primary research studies that have been done by other investigators, looking at real people wearing face masks, and being exposed to an environment where something like influenza is circulating. And you compare the people who wore face masks and the people who didn't, who got more flu.

Adam - And then what kind of things did you find at the end of this review?

Julii - What we found is the evidence is a little complicated. So one thing that had happened is in the previous literature summaries, the science tended to look only at what are called randomised control trials. And that's where people are given the masks. And often it's known who they're being exposed to. And in those situations you've got a group of people who've been asked to please wear a mask, and you've got another group of people who've been asked, please don't wear a mask. And the first thing you find out is that people didn't follow instructions. So you have people who were supposed to wear masks who maybe only wore them half the time or less, and people who weren't supposed to wear masks who wore them some of the time. So then when you compare the results at the end, we might find a small protective effect, but you’re thinking that's probably underestimating the true protective effect.

So that was a problem with those trials, which should be the very best quality evidence. They were often very small trials so you couldn't sort of adjust for other factors, other hygiene awareness. The other type of observational study that can be done, you look at people who've had say, influenza, and you compare them to people who didn't and you compare their habits to see which hygiene habits might be the most protective. And the problem with that is, you know you've never captured all the variables. And in that second type of study, which is called a case control, you typically find much stronger evidence in favor of face masks. But you don't really know. Is it the face mask or is it something I haven't observed? So I think what we found was the evidence is complicated. That said, on balance, we all concluded that there is some protective effect going on most of the time, in the groups that wear the face masks, but it's a small protective effect.

Adam - So what does that mean as a recommendation? Does that mean with coronavirus we all should wear facemasks?

Julii - No, but see that's complicated too because we don't want the public to be competing with healthcare professionals. You have to think how can a face mask protect you? It's going to protect you because somebody put, well, to be crude about it, they've put a little bit of spit into your environment, probably directly onto your face, because they've been talking to you or they've coughed near you, and the people who are going to most benefit from having the face mask are the healthcare professionals. So if us in the public start wearing these masks, are we going to actually deprive them of that protective equipment? The other thing is there's a lot of the time we don't really know what kind of masks people were wearing. So in those observational studies, people were asked did you wear a mask? But they weren't usually asked what kind of mask. So we don't know enough about how protective cloth masks might be for instance. In the deliberate experiments, people were always given surgical masks and we know a lot about their properties and why they could keep viruses out. So in terms of should we all wear masks?

Well they're not very practical because they're uncomfortable. They can cause skin reactions, you have to take them off to eat and clean your teeth, and they usually impede breathing to some extent. So should we all wear a mask? I think the conclusion we came up with is that if people want to wear masks, they've got good evidence that they're giving themselves some protection, but no mask is as good as getting two metres away from someone. So the social distancing where we just don't have that opportunity to pass material, little saliva material between us, is much better than wearing a mask. And it's much more practical a lot of the time. So where would we wear a mask, where would we suggest it? It would be in crowded environments where you can't avoid being close to someone. So the typical example would be on the tube, other types of crowded public transport and possibly crowded shops. Although, where I live right now, there's, there's no such thing as crowded public transport or crowded shops.

Comments

Hi,
thank you so much for the great podcast!

When I listened to "To wear or not to wear a facemask", I thought the information was great, but I was missing what I thought was the core point of wearing simple fabric masks. I live in Bavaria, Germany. It's compulsory to wear masks in stores, church services and public transport at this point in time. But nobody ever claimed that wear surgical or selfmade fabric mouth/nose masks were meant to protect the person wearing it. It has been made clear from the very beginning that these masks serve the only function to catch droplets from breathing or coughing and thus protect others.

In contrast FFP2 or FFP3 masks are meant to protect the wearer. However since they have a exhale valve they don't protect others. The conclusion in Germany is that people in public places should wear simple masks to protect others while medical staff and care personnel require FFP2/2 masks for self protection.

Best regards
Peter Fröhlich

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