02/05/2021

The Thinking Behind New Double-Masking Recommendations

12:09 minutes

a White woman outside in a coat wearing gloves applying two masks to her face, and there's snow on the ground
Credit: Shutterstock

This story is part of Science Friday’s coverage on the novel coronavirus, the agent of the disease COVID-19. Listen to experts discuss the spread, outbreak response, and treatment.


If you’re at the grocery store or taking a walk in the brisk winter air, you might see someone sporting the new pandemic trend—double masks. Sometimes it’s a cloth mask over an N95; sometimes it’s two fabric masks layered together. And it’s not because it’s cold out (although the extra warmth is nice). 

This week the CDC says it’s considering updating its masking guidelines to include wearing two masks, to protect against new, more contagious variants of the coronavirus. 

Sarah Zhang, staff writer for The Atlantic, joins Ira to discuss whether two masks are really better than one. Plus, how the U.K. is studying whether mixing Astrazeneca’s new vaccine with a dose of Pfizer or Moderna’s formula might actually be more effective at obtaining immunity. 


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Segment Guests

Sarah Zhang

Sarah Zhang is a staff writer at The Atlantic, based in Washington, D.C..

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. A bit later in the hour, how effective will vaccines be against new variants of the coronavirus? But first, if you’re out at the grocery store or taking a walk, you might see someone sporting the new pandemic trend– double masks. Sometimes, it’s a cloth mask over an N95. Sometimes, it’s two fabric masks layered together.

If you are already double masked, you may be prescient because this week, Dr. Anthony Fauci said the CDC is considering updating its mask guidelines to suggest wearing two masks to protect against new, more contagious variants of the coronavirus. Here to share more about the thinking behind the double masking guidelines and to discuss other science news of the week is Sarah Zhang, staff writer for The Atlantic. Hi, Sarah.

SARAH ZHANG: Hi, Ira. Good to talk to you again.

IRA FLATOW: Nice to have you back. So we just got used to wearing one mask, and now we can anticipate they’re saying it’s time to up it to two.

SARAH ZHANG: Well, I confess to having been someone who has occasionally worn a double mask myself, mostly in cases where I have been indoors talking to other people, which is kind of the more high risk COVID situation, right? So yeah, what are the benefits of two masks? Well, there are a couple of different ways to think about it. One is you’re obviously just getting another layer of filtration in front of your face, and that just kind of keeps out any particles.

But maybe the bigger benefit is actually having a tighter seal or a tighter fit around your face. I think this is probably especially true if you’re wearing a surgical mask as a first layer, which kind of tends to be fairly loose, especially around your nose and maybe around your chin. And then you might wear a slightly better fitting cloth mask over it, so that you just kind of don’t get that air that’s coming out around your mask, and you’re actually breathing through your mask. I wear glasses, so when I walk outside in the cold, it’s really obvious to me when a mask is not fitting well. But what you’re really trying to avoid is kind of breathing around the mask, rather than through it.

IRA FLATOW: Yeah, I kind of test my masks by putting my fingers on it and see if I’m pressing it, if I’m breathing more through the mask than at the top and the bottom, then I know it’s not a good seal.

SARAH ZHANG: Yeah, exactly. And I think if listeners have been lucky enough to get an N95 mask or one of the KN95s, you’ll probably notice that those actually do kind of sit against your face a little bit tighter. They really do press against your face.

IRA FLATOW: Sarah, why do we need double masking at this time? Has it got something to do with the new variants of the coronavirus?

SARAH ZHANG: Part of it is, one, there’s just a lot of COVID spread in general around right now, but also the new variants are more transmissible. The variants is not like the– it’s not going to have magic powers. It’s not going to automatically jump through your mask. But what might be happening is that you might need less of the virus to get sick. So the double mask is just kind of like an extra layer of protection, an extra precaution to kind of protect us against this more transmissible variant.

IRA FLATOW: There are also reports that the White House is considering sending everyone a cloth mask.

SARAH ZHANG: Yeah, I think we should have probably done this a year ago. I think that would have really helped. I think it would be great to have masks available for everyone. Certainly when I walk around outside, I sometimes still see people wearing scarves. I think it’d certainly be better if they were wearing masks. If we could be getting anyone N95 masks, that would be even better.

IRA FLATOW: Also one of the things we haven’t talked about much is the flu season. It’s run under the radar screen. And there are so many fewer cases of flu. Is that from the mask wearing or just people social distancing or both, do you think?

SARAH ZHANG: Yeah, flu has almost completely disappeared. It’s probably a little bit of both. I think what we’re seeing is better measures that are being used to contain COVID or have been really, really good at containing flu. So, as you mentioned, we are wearing masks more. We’re social distancing, and a lot of schools are also closed.

Or there are also kind of precautions in place in schools. In the past, kids tend to be a pretty big vector for flu, so I think that’s probably another reason we’re just seeing very, very little of it. But yeah, it’s really astonishing if you’re just talking to people in public health. And I think it shows that COVID is a lot more infectious than the flu.

IRA FLATOW: And flu shots, are people getting flu shots at the regular rate, or has that dropped off also?

SARAH ZHANG: That’s a good question. I know earlier last year, people were really trying to encourage people to get flu shots because we were afraid of a, quote unquote, “twindemic” of COVID and the flu. I don’t know if we have the numbers for this year yet. But I think the flu drop offs have been so dramatic that just vaccination alone would not explain it.

IRA FLATOW: Let’s talk about other COVID related news. We got some new data this week from the UK. And the UK is looking into whether you can mix a shot of the AstraZeneca vaccine with a shot of the Pfizer or Moderna vaccine, I guess sort of mixing and match. Tell us how that would work and what they are studying.

SARAH ZHANG: Yeah, the UK is starting a trial to see if you can mix and match these vaccines. So the idea of why you would want to do this is partly just because it’ll be a lot easier, right? When you have all these different vaccines, you don’t have to worry about making sure you have the exactly the same one. It’ll just be easier to administer. There’s sort of no specific reason to think that it would be bad, and there’s no specific reason to think that it would not work. But we always just want to run the trials and have the data to make sure there’s nothing unexpected.

The reason we might think that two different doses of two different vaccines will probably work is because basically, all of the vaccines we have, have a very similar target. So vaccines kind of present a snapshot of the virus for your immune system. And basically, all the vaccines present the exact same snapshot. It’s the spike protein of the coronavirus. And so what’s different about the AstraZeneca vaccine and the Pfizer vaccine is not the snapshot they’re presenting, but the way they’re getting it to yourselves.

IRA FLATOW: Yeah, we’ll be talking a lot more about vaccinations a little bit later in the program. Meanwhile, Johnson & Johnson filed for emergency use authorization on Thursday with the FDA. They were expected to do that. So what is the timeline that we might expect to see the Johnson & Johnson vaccine? And if I heard them correctly, that’s just a one-shotter, is it not?

SARAH ZHANG: Yeah, that’s right. [INAUDIBLE] excitement that it’ll be a lot easier to roll out a one-dose vaccine. So I think we can probably expect it in early March. The process will probably be very similar to what happened with the Pfizer and Moderna vaccines. The FDA is currently going to be reviewing lots and lots of data.

On February 26th, I believe, the FDA advisor committee is going to have a public meeting, which you and I can watch on YouTube if we have a day where we want to do that. And then we can probably expect an emergency use authorization very quickly after that.

The possible limiting factor right now is that Johnson & Johnson doesn’t have that many vaccines currently sitting on shelves, waiting to be used. So I think the latest reporting is that there will probably be single digit millions. So this will be a– definitely be more vaccines, but it won’t be a huge flood of new vaccines yet.

IRA FLATOW: So it could be maybe the middle of this summer or the beginning of this summer before we see any large quantities of the Johnson & Johnson. Let’s talk about this month marking the 20th anniversary of the first human genome getting published. Boy, I remember that back in February of 2001. Can it be 20 years already?

SARAH ZHANG: Did you cover it on this show back then?

IRA FLATOW: Absolutely.

SARAH ZHANG: Yeah, it was huge news, right? I think what was– so what happened 20 years ago is that the first drafts of the human genome were published in the journals Nature and Science. And the reason there were two papers, listeners might remember, is that there was a huge rivalry between a kind of publicly funded group, led by the National Institutes of Health, and then a private company, and they were in this bitter rivalry, racing against each other.

The first drafts were published 20 years ago now. And it was really a first draft. I think when scientists first went through the human genome, they were just really surprised to realize that there were way fewer genes that we expected.

IRA FLATOW: Yeah, that was the big news. How could we have so few genes?

SARAH ZHANG: Yeah, right, and there was a lot of this, quote unquote, “junk DNA.” I think in the 20 years since, we’ve learned a lot more about what this, quote unquote, “junk DNA” is, and it’s probably not so junk. What it probably does is it helps us regulate to which genes are actually expressed. And so there’s been a lot of– we’ve learned a lot in the 20 years, and we kind of filled in the parts of the genome as well that were originally a little bit patchy.

IRA FLATOW: Yeah, we had an unofficial rule on Science Friday never to call it junk DNA.

SARAH ZHANG: That’s a good rule.

IRA FLATOW: Because if it’s been conserved for who knows how many hundreds of thousands of years, we must be doing something with it, right?

SARAH ZHANG: Yeah, and I think we’ve really seen that in the past 20 years of research.

IRA FLATOW: And it’s amazing how comfortable people have become with the idea of reading their genome or getting their ancestry info from it. We’ve developed a whole industry around this. But I don’t think people actually thought a whole lot about anticipating how their genome might be sold to third parties.

SARAH ZHANG: Yeah, I think that’s true. And I think we’re getting some news this week that 23andMe is getting ready to go public as a company. Early on, there was so much excitement about the health information and of DNA. And certainly, there’s been some big advancements, but I think, for the most part, even folks at 23andMe would tell you they’re surprised at how many people are really just interested in the ancestry part, and not necessarily so much the health part.

So I think we’re kind of in this moment where people are really– it’s in consumers’ hands now. We have this democratization of DNA. But there’s a lot that we don’t know about how health might be impacted by your genes and how much is actually environment and your upbringing instead.

IRA FLATOW: The fear back then and I think some of the fear now is still that health insurance companies might deny you coverage if they look into your genome and say, uh-oh, you’re susceptible to such and such a disease.

SARAH ZHANG: Mm-hmm, yeah, we currently do have a law so that health insurance can’t do that. But there might be other areas such as life insurance, where they might be able to look at your genes and deny you coverage for various reasons. So I think as we get more and more genome sequencing, as we’re getting more DNA tests, this will be an issue that continues.

IRA FLATOW: Let’s move on to some final fun creature news. For those of you into reptiles, which so many of us are, scientists say they have found the tiniest chameleon ever discovered. How tiny is that?

SARAH ZHANG: It’s as small as a sunflower seed and can fit on the tip of your finger.

IRA FLATOW: How do you find one like that? I mean, I can easily say that’s why they’re there, and we’re here, because that’s not our job, but how do you do that?

SARAH ZHANG: Yeah, that’s a great question. I don’t know– I wish the scientist who discovered that told us a little bit more. But this chameleon is [INAUDIBLE] in Madagascar, and it kind of lives in the leaf litter, the dead leaves that are on the floor of the rainforest. And so it seems to eat other tiny bugs even smaller than it. I don’t know who was painstakingly going through the leaf litter to look for this very, very tiny reptile.

IRA FLATOW: Do they think there might be even a smaller one out there?

SARAH ZHANG: Yeah, that’s a great question, right? We obviously do have smaller animals that are insects. But there might be some theoretical limit to how small a reptile can be. One problem is that when you’re smaller, your surface area to volume ratio is bigger. So this means water starts evaporating from you faster.

Now insects, obviously, have these hard shells that protect them. But are reptiles– do they have a limit to how small they can go before they– just kind of, the laws of physics don’t work anymore.

IRA FLATOW: [LAUGHS] All right, thank you very much for taking the time to be with us today.

SARAH ZHANG: All right, thank you.

IRA FLATOW: Sarah Zhang, staff writer for The Atlantic.

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