Coronavirus (COVID-19): Press Conference with Joseph Allen, 04/2/20


You’re listening to a press conference from the Harvard T.H. Chan School of Public Health with Joseph Allen, assistant professor of exposure assessment and director of the Healthy Buildings Program. This call was recorded at 11:30 am Eastern Time on Thursday, April 2.

Previous press conferences are linked at the bottom of this transcript.

JOSEPH ALLEN: Thanks for joining us. My goal for this time here is to be a resource to you to answer questions among all of those themes. And I thought maybe I’d just give you one minute of background about myself to explain maybe what our academic titles actually mean in practice. And that can help guide this discussion.

So, I direct the Healthy Buildings program. And, prior to joining Harvard, I worked in consulting and led forensic investigations of sick buildings. This includes cancer clusters, and it included disease outbreaks, including high-profile disease outbreaks in hospitals where you had lives on the line. And, in many ways, this reminds me of all of this consulting and forensic work I’ve done.

Of course, none of us have ever seen anything to this scale, but, essentially, the same principles apply. We have limited information. We have high stakes. And we have to make decisions based on the best available scientific evidence we have now. And my approach is to follow the precautionary principle and is take action and decisive action, even in light of uncertain evidence, sometimes, all with the goal of minimizing risk.

In addition to that role, I do a lot of work on worker health. I’m a certified industrial hygienist, and I bring that up because it’s an expertise you may seek out in other experts. The field industrial hygiene is all about anticipating, recognizing, evaluating, and controlling hazards in the workplace. So, this is exactly what we do all the time in offices, schools, homes, factories, hospitals. You name it.

And so, I want to bring that in as another area we can talk about. And it relates to what I think is an important topic right now that’s bubbling up, and that’s the use of masks. So, industrial hygienist, I’ve had a lot of experience in masks and fit testing and understand this very well. And I’m happy to take questions on that topic as well.

Last, I’ll say, as a resource, I have a book coming out written with a Harvard Business School professor called Healthy Buildings. It comes out on April 21. And, not intended to plug the book for sales or anything like that, but I just wanted to give it as a resource because we talk about these mega changes that are influencing our world and how buildings can either make us sick or keep us well.

And we give strategies that go beyond disease transmission and include disease transmission, but also go beyond it to think more holistically how to keep yourself healthy indoors. So, I’ll stop there and happy to answer any questions along any of those topics.

MODERATOR: Alright, it looks like our first question.

Q: Hi, Dr. Allen, thanks for taking the time to speak with us. Regarding masks, I wonder if you have any thoughts on the current CDC task force guidelines for the general population, as it pertains to the use of masks. And, secondly, and forgive me if this is outside your area of expertise, but I am curious generally for your perspective on the arguments that we’ve heard from like our governor in the state of Florida in terms of not wanting to – if there are any risks from the desire to not want to shut down or have stay-at-home orders in communities that don’t have confirmed outbreaks.

JOSEPH ALLEN: Sure, so I can separate both of those. And, on the mask side, yeah, my feeling is that the general public should be wearing masks. I have a piece coming out on this shortly. And because – well, I can walk over where I see four ways in which masks provide a public health benefit and as a rationale for why they should be deployed right now.

On your second comment, I’m fully in favor, and I believe the models support this. I know the model support that we should be enforcing social distancing everywhere right now. And that’s for a couple of reasons.

One is we need to get a handle on the extent and scale and scope of the crisis we’re facing and give our front-line health care workers a chance to respond to this first wave. The incubation period, as you all know, is several weeks before – or the incubation period is up to 11 days, but the time before people present at the hospitals is up to two to three weeks.

So, we need to be prepared for that first wave and give our front-line workers a chance to address that. And, maybe most importantly, even in communities that don’t currently have it, this virus is highly contagious, as we know, and we’ve seen. It spreads rapidly. And it spreads via asymptomatic transmission.

So, a community that doesn’t have a case today, or a confirmed case, doesn’t necessarily mean they don’t have any cases there. And it’s clear to me, as we’ve seen from around the world, that communities that maybe think they were not impacted are quick to be impacted. This is a virus that’s not going to spare any community.

MODERATOR: OK. The next question.

Q: Hi, thank you so much for taking my question. Just a follow-up on that last question about masks, when you’re talking about masking the general public, are you talking about if they had access to surgical masks or cotton masks? I know there’s some data that shows that cotton masks are much less protective than surgical masks, maybe because of the amount of particles that can get through and then also moisture that can build up on them. Can you talk a little bit about that?

JOSEPH ALLEN: Yeah, I’m happy to. And thanks for both questions. And I’m glad you asked that follow-up one because there’s a lot more nuance in the mask conversation. And I gave my high-level opinion and advice. And it’s a nice chance to support it and give you the rationale for why.

So, first and foremost, the science supports general public wearing masks. At the same time, the general public cannot be using masks that need to go to health care workers and other front-line workers. And these are the N95s and the surgical masks because of the shortages that we’re experiencing, and we will continue to experience for the next several months. So, my recommendation there is we need to be using homemade masks.

And so, you asked a question about efficacy. And so, here’s how I see the – here’s where I see four pillars of a public health benefit for wearing masks. First, it’s to help prevent the spread through large droplets, through coughing and sneezing.

So, it benefits others if a wearer, if a person wears the mask, who is symptomatic or asymptomatic. It prevents them – in the event they cough or sneeze and are shedding virus, it prevents that, the opportunity to infect others who are nearby or contaminate surfaces where you could have fomite transmission. I could sidebar on what fomite transmission is. So that’s one.

Second one, you mentioned it doesn’t provide the same benefit as an N95 or other masks, and that is absolutely true. These homemade masks is what I’m talking about. And that’s true, but, actually, for the wearer, it does provide some benefit. And there have been studies looking at, say, for example, the use of a 100% cotton t-shirt made into a homemade mask does have an efficiency anywhere between 50% to 70%. So, while it’s not as good, it’s better than nothing.

And that’s one of the reasons I think we should be doing this. Similar to all the other approaches we’re taking, it’s an all-in approach. We need to be taking every step we can to minimize disease spread because of the context of what we’re facing.

It’s a pandemic. Risk is everywhere. We’re trying to minimize risk everywhere we can. So, first and foremost, you want to stay home, avoid close contacts, keep physical distancing. If and when you have to go out for groceries or other necessities, this is one more line of defense.

To be clear, it doesn’t replace any of these other public health interventions like handwashing or others, right? We wouldn’t say wear a homemade mask, and then you can stop social distancing. It’s just one more layer of protection. And the scale and scope of what we’re facing I believe requires or mandates that we take every precaution we can.

There are other benefits, the two others. One is having a mask on is a reminder not to touch your mouth and nose. It serves as a physical barrier, but it’s also a constant reminder. And this is important because we know this is a place for transference from fomites or contaminated surfaces that have virus on it. And that’s a way for the virus to find or take residence in your body.

The fourth one I think is around social values and social benefits. Wearing a mask is a social cue. It’s telling others that you’re aware of what’s happening out there. It’s a statement that you’re concerned about protecting them and others. And, as more of us do it, it can be a source of re-emphasizing taking all of these precautions that we’re taking.

So, for all those reasons, I’m on the side that the public should be wearing masks. And, to be clear, when I say masks, I mean homemade masks.

Q: Great, thanks. So, I have a follow-up question to that. And then, if it’s OK, I’d like to ask one more question.

So, my follow-up question is, just curious, you mentioned that having a mask on can help people – keep reminding people what the situation is and not touch their faces. But other experts have sort of said the opposite that they might be concerned that having a mask on could make them touch their face more. And, if they’re touching the outside of the mask, they could potentially contaminate their hands.

But I had trouble finding data to support that concern. Do you know of any? Or do you have any thoughts about sort of the other side of that argument?

JOSEPH ALLEN: Yeah, no, I don’t know any data on that. I’ve seen that argument. And I think it’s valid in the sense that, probably on this phone call, we could come up with 1,000 scenarios where this wouldn’t work.

And so, sure, there are many ways where this could not work. If somebody wears it wrong, they’re touching their face, right? But the idea here is that you don’t just throw this thing on and forget about it. No, you still take those other precautions, and that includes putting it on right, taking it off, not touching your face, not touching around the sides, not adjusting it all the time.

So, it’d be kind of the same thing. We could have this same discussion if I said the recommendation was to wash your hands. And you said, well, what if somebody doesn’t wash their hands correctly. And that’s fair and valid, but, also, I think misses the larger point.

Q: Thank you. OK, so one more question. I’m sorry if I’m taking up all the time. But I wanted to ask you if you had any recommendations for people when they go out. Now that so many people are under stay-at-home orders, sometimes, they might only go out for groceries or medical reasons or something like that. Is there any – and there’s been sort of – is there any precautions you think people should take, besides distancing and handwashing and covering your cough, stuff like that, mask wearing?

Is there anything else that you would recommend people do when they’re out and when they also come back into their house? Like some people have said they take all their clothes off and run in the shower. Some people spray like bleach solutions on their produce and stuff like that. What kind of recommendations would you have for people?

JOSEPH ALLEN: Yeah, I wouldn’t recommend any of those strategies. So, first, let’s talk about when you’re outside. I think you named all of the tried and true strategies.

And, honestly, being a public health and public health scientist, it’s really nice to see the basics of public health coming to the forefront here on how to keep ourselves healthy. And that includes handwashing, getting outside, getting some exercise, sleeping well, and all those other good guys. But I think you hit everything that I would say that you want to do when you’re out in public to take precautions, including limiting how often you have to do that and only doing it when it’s necessary.

And, on returning home, I don’t recommend those types of things that we’ve seen in social media and reported elsewhere. I think, coming back in, you take your shoes off at the door. And this is just good practice.

We have a report we call “Homes for Health – 36 Expert Tips to Make Your Home a Healthier Home.” That’s just good practice, not necessarily related to what we’re experiencing here. But washing your hands right away is a good practice.

There’s a lot of other steps you can take in your home to help minimize the potential for disease transmission like opening up your windows. If you have a portable air purifier, you can run that. Portable humidifier, you can run that and then washing your hands, like I said.

Now that’s a different guidance than I’ve given to other people, two different maybe scenarios. One is someone in a high-risk occupation like a health care worker or if you have someone who’s sick in the home.

And there’s a couple other precautions you would take. I have a piece on USA Today on that. But I’m happy to walk through some specific scenarios. But, if you’re talking about general public, I think I covered the basic precautions you would take, yeah.

Q: OK, great, thank you so much.

JOSEPH ALLEN: Thank you.

MODERATOR: The next question.

Q: Hi, so I wanted to ask you about what we know today about aerosol transmission because I’ve read a lot about that, but I want to know do you know like how is the six feet still the recommendation that people should stay away from each other. I mean what’s currently – what do we know exactly about aerosol transmission?

And, also, related to that, if you have someone at home who is sick, is air conditioning – I mean, is there anything you should take into account with your air conditioning system? Should you just turn it off and open the windows? Those are some of the questions that we’ve had from our audience, and we’d like to address them. Thank you.

JOSEPH ALLEN: Yeah, two great questions there, thank you. So, first of all, let me address airborne. And this requires some nuance and care. So, I encourage you to stay with all of the discussion and not jump on any one quote somewhere because I think it’s really important to get this message right.

So, typically, when we think about modes of transmission, we break it down into three primary modes. You’ve probably heard of these so far. But, large droplet, and this would be things like, when you cough or sneeze the large, sometimes visible droplets, but, most of time, not.

And they’re large, and they tend to settle out pretty quickly, meaning they’re heavy. And they fall to the ground. And that informs some of our public health intervention strategies like maintaining a six-foot distance, cleaning surfaces, right?

A second mode of transmission is called fomite transmission. And that’s simply the name for an inanimate surface that has been contaminated by someone who’s infectious and serves as a point of transference to someone else. So, if I’m sick, and I touch my mouth, and I get some virus on there, and I touch a doorknob, and you come along next, the door knob is a fomite and could be a place where you pick up the virus. That informs intervention strategies like surface cleaning and cleaning high-touch objects and not touching your nose or mouth and washing your hands of course.

Third one is this airborne or aerosol transmission. And this talks about transmission from inhaling smaller viral particles. But, before I go into detail on the aerosol transmission, I should note to that this construct of these modes of transmission is a little bit of a false – not a little bit. It’s a false construct. It’s really a continuum.

So, imagine I sneeze, and I’m infectious. Well, there’ll be some visible droplets that fall right out. There’ll be large droplets that settle out. And there’ll also be some fine droplets that stay in the air for longer. And some of this might land on a surface that you’ve touched. So, in that way, just in that one scenario, you can see how all three modes of transmission would be operating.

The guidance for staying away six feet also helps against airborne transmission because, while smaller viral particles can stay aloft and spread out in a room, for example, beyond six feet, it’s also a function of let’s call it dose. So, if you’re close to me, and I cough, and, even if I miss you with these large droplets, the airborne droplets, there’ll be more of them, these smaller particles, aerosols, that you could inhale. If you’re 12 feet away, by the time it reaches you, it’ll have dispersed. So, they might be in the air, but there’ll be fewer of them.

And other things start to come into play like air exchange rate. So, if your window is open, if you have a portable air purifier going, it’ll also act to reduce some of these airborne concentrations.

So the idea that – airborne is a word or phrase that tends to or can cause anxiety, but it’s related to those other factors. And it’s important to recognize that, even if something is airborne, it dilutes in space.

So, certainly, take outside for example. If I cough or sneeze or you’re near someone who’s outside, maybe you’re 6 feet, 10 feet, 15 feet away from somebody. That’s going to disperse really quickly because you have wind and a large volume of space. Even in a home, that’s going to disperse.

So, I don’t mean to – I don’t mean to be underplaying airborne transmission either. I’m on record going back to a first piece I wrote about how healthy buildings can help us fight coronavirus that published in Financial Times in early February saying that the potential for airborne transmission exists. I think it’s clear there’s evidence that all three pathways are operating.

Some of this, my early hunch on this, before even some of the science started coming out specific to this virus, was, like I said, I did a lot of these forensic investigations of sick buildings. So the first time I saw these stories, these really high-profile case studies, and where a lot of people were getting sick, like the Diamond Princess cruise ship, the Kirkland Senior Center, the Biogen conference, or, even more recently, the choir where there’s this big outbreak, and they were taking some precautions around distancing and handwashing, and still you see a really high prevalence of people who got infected. So, it tells me that most likely, multiple modes are operating.

And the last thing I’ll say on this is it informs control strategy, or it should, right? We could spend, and scientists will spend, months and years trying to resolve which mode of transmission dominates for this novel coronavirus. We may not be able to figure it out. In fact, we’ve been studying influenza for decades and haven’t figured that out.

To me, it’s a little irrelevant to what we’re facing right now because, if we know all modes are likely operating – and, certainly, CDC and others say it’s dominated by droplet and fomite – we should be throwing everything we have at this, every intervention we can that addresses all three, because it’s the smart and appropriate precaution to take.

We don’t have the luxury of waiting three months, six months, a year to figure out which mode is more important than the other because of what we’re facing. So that was a long answer, but I think it was worth it because the airborne discussion is a hot topic. It’s also a hot button topic. And I think all of that nuance I described is really important when we think about how we describe it and talk about it.

MODERATOR: Our next question.

Q: Hi. My question is about asymptomatic transmission and the best way– what is the best, most accurate information about that? And I have a reason for asking this question specifically. And that’s because the University of Arkansas has directed its close to 30,000 students and staff to a page with web resources about COVID-19.

And, on that website, there is a section about transmission. Included in that section is this statement, which I’m going to read exactly as it is on the website. “It is possible to catch COVID-19 from someone who has no symptoms. However, at this time, it is considered to be low probability.”

And I did ask the university what was their source for that statement, and they referred me to the World Health Organization. And, sure enough, the World Health Organization does use the phrase, quote, “very low,” end quote, to describe the risk of catching COVID-19, quote, “from someone with no symptoms at all.”

So, the question is, what is the best, most accurate info we have about asymptomatic transmission and if you have any comment – you may or may not – about the way the University of Arkansas and, perhaps, the World Health Organization describe that probability or chance?

JOSEPH ALLEN: Yes, that’s a good question. And I’ll say this. One, I think organizations, large and small, are doing their best to stay on top of what is a really fluid situation with, by the time we’re off this call, there’s probably going to be two or three new preprints or studies that are out to stay on top of. So, I’ll caveat it with that.

The second thing I’ll caveat is I don’t know the specific numbers. You’ll have to check another source on the percent of asymptomatic across the various reporting agencies or what we saw in Wuhan versus Italy versus what we’re seeing in the US.

And it’s quite difficult because we don’t have the full testing in place. And I mean the two types of testing, testing to determine who has it and the serological testing to determine who had it. So, it’s quite a difficult question, although there are case reports showing that asymptomatic people have transmitted it to close contacts. That is definite.

I also think – I’m going to weigh in on any specifics from the website, on either website, but I do think it’s worth talking a little bit about the language we use, just broadly speaking, and that low probability might mean something different to you and me. It might mean something different to somebody else on this call.

And so, there’s absolute risk and relative risk. So, it’s also a matter of, relative to symptomatic transmission, it’s lower. Whether or not you describe it as a low probability or otherwise or WHO, which it sounds like you quoted as very low probability, I think it’s worth just reporting on the actual numbers.

It’s clear that asymptomatic transmission is occurring. And it’s one of the reasons why this virus is so challenging. If everyone who was transmitting was symptomatic, it would be – all of these stay at home or don’t go to work early on when you’re sick, that early on guidance we got, would have helped to control this.

But we know that people are shedding virus, even while they’re asymptomatic or even have mild symptoms. So that is borne out. Yeah, but I don’t have the specific percentages for you.

MODERATOR: The next question.

Q: Thank you again for just a follow-up on that question about asymptomatic transmission. I know there’s been – like you said, people have been trying to figure out how influenza spreads for years and haven’t quite figured it out. But is there any information that could be useful there in terms of, if there is asymptomatic spread, what mode of transmission might that be?

I mean, obviously, respiratory droplets go farther, and there may be more of them when people cough or sneeze. If there’s asymptomatic transmission, is it more likely to be fomite, aerosol, or maybe respiratory droplets still? Is there anything like that? It feels like it’s a pertinent question, especially in terms of the discussion about masks.

JOSEPH ALLEN: Yeah, it’s a great question. And I’d put that along for me. And I’m trying to land a piece on this right now on as a line of evidence that airborne transmission is happening. I would agree with you. I mean asymptomatic literally means no symptoms.

No symptoms means no coughing or sneezing. That means transmission must be happening in another manner or at least not frequent coughing or sneezing, no symptoms.

And, if you look at studies on patients with influenza, it shows that infectious virus in fine particles, so the small aerosols, can be released just by breathing and talking, which makes sense. I mean, if you think about just being in the proximity of someone, you would pick up on this.

And so that’s interesting, but a third part of that or line of reasoning in there is that a study that’s specific to SARS-CoV-2 shows high shedding of infectious virus in the throat pre-symptoms. So, at least for me, you start to piece together the evidence. And it suggests that airborne transmission is happening – asymptomatic, there’s less coughing or sneezing. We know that normal talking and breathing releases fine aerosols and we know that there’s high viral shedding – there’s viral shedding in the throat pre-symptoms.

So, again, I think this is another way to think about, at least for me – and it goes back, I think, to my days doing the forensic investigation work – is we don’t have all of the answers right now. But we don’t have the time to wait for all of the exact answers here. To me, there’s enough evidence to suggest this is a mode of transmission that’s important, and we need to be taking precautions to address it.

I mean, look, so, in a building, that means more fresh air, higher levels of filtration. And I have a hard time figuring out what the downside risk is to that. People open their windows a little longer, maybe a little higher energy use during this pandemic in buildings, as we try to increase the ventilation rate.

So, to me, the trade-offs there are quite small. And the benefits are potentially quite large. So, like I said, I’ve been arguing in public pieces, another one in The New York Times in early March, about what you can do in your building. And I mentioned the potential for airborne transmission as a rationale for employing some building-level strategies that address the potential for airborne transmission.

MODERATOR:  Next question.

Q: Hi, sorry, so I just wanted to ask a follow-up. And so you just said that it could be – that it’s a good idea to open the windows. So, in that sense, I mean, should you like, while you’re opening the windows, also like turn off your air conditioning? Is there anything – you know, you were talking about using the air purifier, the portable air purifier. So, is that that would be like a good idea, especially if you have someone sick at home?

JOSEPH ALLEN: Yeah, so I think it’s kind of like our other discussion about masks. And I think we have to separate out general guidance versus specific guidance, right? Every home, every school building will be different. Every hospital will be slightly different. So, I’m talking here about general principles.

It’s hard for me to say something specific about some situation because there are air conditioners that don’t recirculate air. There are some that do just recirculate. But, in general, the high-level principle is this. You’re trying to bring in more fresh outdoor air to dilute indoor contaminants. And that includes, on a normal day, chemical contaminants. And, in this environment, we’re trying to reduce any potential biological or airborne virus.

So, if you have an air conditioner, and it draws in 100% fresh outdoor air, you should run that. That’s good. If you have the type of air conditioner that only recirculates the air, that is not what you want, right? We don’t want to just be recirculating the air. When we say ventilation rate, we mean outdoor air ventilation rate, not just moving air or treating or conditioning air for temperature, but bringing in fresh outdoor air.

What’s happening in our buildings, going back to the ’70s, is that we’ve started to choke them off from the outdoor and the natural world, including making our buildings so energy efficient that we’ve stopped letting them breathe. And what we talk about, in terms of a building breathing, is the air exchange rate. And that’s the amount of fresh outdoor air that comes in every hour.

And so, we’ve gotten so good at making our buildings airtight – not quite airtight, but we’ve tightened up the building envelopes – that air exchange rates are actually quite low in homes and offices and buildings, which is great for energy, but it’s terrible for indoor air quality. So, one of the goals here is simply to bring in more fresh outdoor air.

On the filtration side, there are strategies also to remove indoor pollutants and particles and aerosols that are particles. And that’s through the use of a portable air purifier. Again, the details matter, right? The sizing of the device matters.

You can’t put a small portable air purifier in a gymnasium at a school and think it’s going to be effective. So, it has to be sized right for the room. It should be HEPA filtered H-E-P-A, HEPA filtered, which is high-efficiency filtration. That captures 99.9% – 99.97% of particles. So those details definitely do matter, but they can be quite effective at controlling airborne particles in a room.

Q: All right, she is writing about the future of sports after coronavirus and is wondering if the concept of social distancing will impact both the players, media, and spectators. Do sports have a unique niche to lead the charge in cleanliness and having advanced measures to prevent virus outbreaks such as having more hand sanitizer at arenas and stadiums or less fan interaction with players?

What about fans sitting in every other seat? Also, when do you think sport should look into coming back? And what could they look like after it when they start?

JOSEPH ALLEN: Wow, this is a great question. I’d love to work with you on a piece to really explore this because there’s lots of interesting threads there, and I hope I remember them all. And I can give you my first thoughts. But, yeah, there’s a lot to unpack there.

I mean, first, I think it’s – even though there’s a lot of uncertainty right now, I think one thing is very certain is that people’s expectations are going to change. And our awareness levels are going to change. The first time everyone is back in a large setting, be it on Broadway or at a concert or at an NBA game, I think people will be looking at the environment differently.

And, by that time, whenever that is, we’ll all have been practicing some aggressive forms of social distancing. And so, what seemed – what once seemed maybe awkward, you know, your first conversation with a neighbor where you had to stay six feet apart, is now quickly becoming the norm. And I think it’ll stay the norm with handwashing.

So, people’s expectations will be different. And I think the sports world needs to be prepared for that in thinking about how we repopulate or restart these engines.

I do think there’s a huge role for the sports world to play here, one, as being a model of behavior and responsible activity and actions they take in their arenas. So, people look to the sports world. Many people look to the sports world for role models and examples of how we should be leading. Or it’s certainly a leadership moment for the sports world and every business.

And I think – I can’t predict what the let’s say returning to sports looks like, but I’ve been thinking a lot about how we repopulate our buildings and offices and schools. And it’s going to be different. So, I think it’s time to put in the intellectual work to think, well, if we get back to going to a ball game, does it mean skipping? Is that a nice interim solution that lets us restart the economy and this particular piece of the economy by having people come every other seat or every two seats or requiring handwashing or putting hand sanitizer all over the stadium?

I think we’re going to see a lot of that. And I think the expectation will be there too, whether or not the risk – independent of risk, it’ll be about perceptions, about how people do or don’t feel safe going back into these crowded environments. My feeling is, and having worked with some of the worst possible or worst-case sick buildings, is that any building can be made better. And that’s through design changes in a building, operational changes, behavioral changes, nudges you can make.

So, I haven’t come across a space or a building or a building type where you can’t minimize risk and get to a point where people feel comfortable being back in that space. I don’t know when that is for the sports world, but it’s something they should be thinking about soon and thinking about creative ways that we can start to get back to normalcy or a new normalcy, whenever that is.

Q: Hi, thank you so much for your time. I wanted to ask about personal protective equipment, specifically for health care workers. I’m writing about local donation drives. I was wondering if you could describe the ways that PPE reduce the risk of transmission, especially for health care workers. And we’ve heard so much about a need or a shortage of PPE. And I guess, if we’re talking about some of the worst-case scenarios, what that might mean in terms of increasing the risk to health care workers?

JOSEPH ALLEN: Yeah, I mean, what we’ve seen – well, clearly, there’s a shortage of PPE. This is real. It’s a problem. And health care systems are adapting. We’ve seen that the risk to health care workers is quite high, and this is everywhere that’s experienced an outbreak so far – Italy, China, South Korea. The risk is really high for health care workers.

And, well, there’s a lot of reasons that’s the case, but, primarily, it’s the amount of frequency and duration of exposure to sick people who are shedding virus. And, early on –  and I mean early on in the epidemic when it was just an epidemic, before it was a pandemic – we didn’t know as much about how this is transmitted.

And now you see a heightened awareness, and it’s led to changes. So, in other words, early on, maybe patients, only when they were confirmed or symptomatic, were put into specialized negative pressure rooms in a hospital. I know hospitals now are turning entire wings into negative pressure. People are being treated or triaged outside of the emergency room now. So, there’s a much bigger effort let’s just say on the behavior side of this or building operations side to treat everyone as infectious, not that hospitals don’t do that, but I guess an extra layer of attention to this.

When we think about protections, you want put all of these other controls in place. And the last control, the last line of defense, is PPE. And this goes beyond the masks and the N95s, but it gets to gloves, wearing goggles, face shields, making sure they have access to hand sanitizer, and so what are really some of the basics of PPE for health care that the health care workers are really familiar with anyway.

What’s different here is that they’re not familiar with not just disposing them after a visit with a patient, to have to wear that PPE, the same PPE, all day. And, already, there’s discussions about trying to clean PPE or preserving it even for longer.

Traditionally, with PPE, it’s single use, disposable, but OSHA has – that’s the Occupational Safety and Health Administration, which regulates this – has started to or has policies in place – and CDC does too – or guidance for these emergency situations where some of these standards have to be relaxed. Maybe relaxed isn’t the right word. They have to be adapted to the current situation, which is the PPE shortage.

So that’s why you’re having people wear PPE for longer. Normally, to wear an N95, you have to be fit tested every 12 months. And so, some of those rules are – relaxed is not the right word. They’re not going to be enforced as strictly because of the extreme extenuating circumstances we’re facing.

Q: Can you quickly explain, in the worst-case scenario where there is a shortage – and that may be already in a few places now. And, certainly, internationally, I think it has been. Although, I don’t know that for sure. But, if there is a true shortage where the supplies are not available, how does that increase the risk for health care workers?

JOSEPH ALLEN: Well, I mean, the PPE is effective at reducing exposure to biologicals and, particularly, this virus and others. All right, so, first and foremost, it acts as a physical barrier or a shield. So, if you have goggles or a face shield on, you’re physically barriering – it’s a physical barrier.

And then they also face risks that we don’t face in the general public like there are procedures that generate aerosols, medical procedures that generate aerosols. So, they’re at a higher risk with the amount of – because of the amount of people around them and also the types of procedures that they’re doing.

Some of these act as a physical shield. If you’re wearing an N95, that’s going to capture 95% of particles. It’s fit to the face, and it should be fit tested, meaning it’s been tested and shown and proven to be effective on that person. Not just the mask performs, but, actually, are they wearing it correctly? Is the shape of their face such that you get a good seal with the mask?

But PPE works. And wearing gloves works, right? This why a health care system does it. So, what will happen is that the risks are higher for health care workers. There’s no question about that if we have – because of this PPE shortage.

MODERATOR: OK, it looks like we might be done with questions. Dr. Allen, do you have any final words you’d like to say before we end the call?

JOSEPH ALLEN: First, I want to thank you all for taking the time to talk with me and ask these questions and, also, to take time and interested in writing about these. I think these are critically important topics. We’ve known for a long time that how we manage our buildings determines our health. And, actually, the decisions we make today regarding our buildings will determine our collective health now and also going forward.

The last thing I wanted to say is a public health message. It actually comes – I’ll paraphrase from my dean or apply it. She’d like to say, whatever your skills, whatever your passion, there’s a place for you in public health.

And I think we have to extend that right now to what’s happening in the world to everybody. This is an all-in moment like we’ve never experienced. And I would encourage everyone, whatever your skill or passion is, to apply it.

And that means, if you’re a comedian, make us laugh. If you’re an artist, bring us some joy and relief. If you’re a scientist, keep doing the science. Reporters report. If you’re a writer, write. Caregiver, you know, take care of people. Teachers, educate. So, it’s really a time for all of us to come together and apply everything we have to help one another through this, whatever skill you have. Thanks.

This concludes the April 2 press conference.

Caroline Buckee, associate professor of epidemiology and associate director of the Center for Communicable Disease Dynamics (April 1, 2020)

Bill Hanage, associate professor of epidemiology (March 31, 2020)

Howard Koh, Harvey V. Fineberg Professor of Public Health Leadership (March 30, 2020)