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All Podcasts Toolkit: How to Stay Safe in COVID Winter

Toolkit: How to Stay Safe in COVID Winter

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Description

With COVID-19 cases surging around the country and winter fast approaching, this may be the most important toolkit episode yet. Infectious diseases physician Nahid Bhadelia and indoor air quality expert Richard Corsi answer every tough question about winter safety – from holiday gatherings, to indoor dining, and flu season. Understand what’s happening with indoor particles and how to make sure homes, offices, and schools can be as safe as possible with ventilation, filters, and CO2 meters. Andy and Lana team up for the episode they say they learned the most from. And be sure to stick around for a very nice surprise at the end of the show.

 

Keep up with Andy on Twitter @ASlavitt and Instagram @andyslavitt.

 

Follow Nahid Bhadelia @BhadeliaMD and Richard Corsi @CorsIAQ on Twitter.

 

Keep up with the work of Dr. Bhadelia and her colleagues at Boston Medical Center @The_BMC on Twitter.

 

In the Bubble is supported in part by listeners like you. Become a member, get exclusive bonus content, ask Andy questions, and get discounted merch at http://lemonadamedia.com/inthebubble/.

 

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Check out these resources from today’s episode: 

 

To follow along with a transcript and/or take notes for friends and family, go to www.lemonadamedia.com/show/in-the-bubble shortly after the air date.

 

Stay up to date with us on Twitter, Facebook, and Instagram at @LemonadaMedia. For additional resources, information, and a transcript of the episode, visit lemonadamedia.com.

Transcript

SPEAKERS

Dr. Nahid Bhadelia, Andy Slavitt, Lana Slavitt, Dr. Richard Corsi

Andy Slavitt  00:10

I’ll start with some music if you guys will allow it. Here we go.

Andy Slavitt

Welcome IN THE BUBBLE. It’s Andy Slavitt, winter edition. We have a great show today. I’m so proud of what we’ve been able to deliver on this episode, that I’m not going to waste a lot of time before getting there. We’re really going to talk about, I think, a really important topic, which is how we get through this winter, safely with family, etc. This is a horrible time for the virus to spread. And it’s a really bad time to be trapped indoors, other the things you can do. We are going to have a toolkit to help you figure that out. Let me tell you about the two experts that we have on the show today, because I think they are incredibly unique. The first is Nahid Bhadelia, she’s an infectious disease physician, and the Medical Director of the Special Pathogens Unit at Boston University. She is a phenomenal expert in public health.

Andy Slavitt

The second person is a really, really interesting, his name is Richard Corsi. He is an internationally recognized expert in the field of indoor air quality. It is not every day that you get to talk to somebody who is that specialized an expert, and everything that you need to know about being indoors and things safe. He can help us with. Look, there’s obviously other elements of getting through this winter, it’s a lonely time, we had an episode, check in an episode on mental health, I’d encourage you to listen to that from a few weeks back. It’s a time when we have holidays coming up. And we’ve maybe getting together with family and we need to be very concerned about that. We’re concerned that our loved ones are isolated. I think the wrong reaction to that is to put them in danger. But let’s get these folks on the phone. And I think you’re really gonna love this episode.

Andy Slavitt  02:55

Hi there.

Dr. Nahid Bhadelia

Great to meet you, Andy. Richard, great to see you.

Dr. Richard Corsi

Hi, how are you?

Andy Slavitt

You guys know each other?

Dr. Nahid Bhadelia  03:01

No, on Twitter as of last week.

Andy Slavitt

Oh, all right. Welcome to winter, everybody. It is our winter episode. No, not Christmas music. But really, we’re gonna have a toolkit episode today with some great people on really how to get through winter safely. I know a lot of people are worried about this. We sent out a request for questions. We had a lot of great questions. So we’re gonna try to cover a lot of ground. And my co-host Lana is here. She’s in a different part of the house.

Lana Slavitt

Hi!

Andy Slavitt

Let me just reintroduce our guests for you. Also, I mentioned already, Nahid Bhadelia and then Richard Corsi, we’re just going to go by Nahid. And we’re going to go by Rich, in that way everything will be just simple and straightforward. But Hi, guys, thanks for coming on the show.

Dr. Nahid Bhadelia

Thanks for having us.

Dr. Richard Corsi

Yeah, thanks, Andy.

Andy Slavitt

That first one was Nahid, the second one is Rich, now you know. Okay. So winter is here. And I wonder if maybe you can give maybe starting with you need just some general overall sense of confidence or some overall thoughts people might have as they head into winter? Can they stay safe? What’s your overall guidance?

Dr. Nahid Bhadelia  04:10

Yeah, I think that the biggest concern going into this period between now and when a vaccine might be proven to be efficacious could make it to the general public is that this is also the point where we’re starting off where we’re seeing a lot of community transmission of this disease. And so we’re starting off at our higher point than we were, you know, over the summer, because over the last month in October, 47 states have reported increase in their hospitalizations and we’re seeing the deaths go up. So the concern is, no matter where you are in this country, this is not a good place to start off a season where naturally the virus seems to have a much greater efficiency of being able to transmit between people. It’s also a period where people are moving indoors, and it’s a period that we might be walking into each other’s homes with holidays, you know what the travel that we’re seeing with students returning back from college is a potential setup of, you know, those community transmission trends from different states from different communities now intersecting with each other.

Andy Slavitt

So, now you got us worried, that’s fine. We started off worried, but what given the overall guidance for people just sort of rules of thumb want to start with?

Dr. Nahid Bhadelia

Yes, I should say that the biggest part of this is, you know, that we can protect ourselves. And we do know how protect ourselves from getting this virus. And it might sound so simplistic, but it is as simple as putting on a mask, avoiding indoor spaces with large number of people, and ensuring that we, you know, do good hand hygiene and when we are in public, you know, taking those steps to keep that physical distance from other people. Because it sounds so simplistic, I think people don’t want to believe that it’s going to have such a huge impact. If you need to look at the success story of every other country that’s managed to drive this transmission down. That’s how we’ve done it. And as long as we follow those, and those around us follow those rules, I think we can make it through this winter without seeing major spikes.

Andy Slavitt  06:10

Well, that’s good to hear. Yeah, one of the things for sure, is we’re going to be indoors a lot more and Rich that’s why we invited you on the show because your expertise is an indoor air quality. And you know, every expertise has its moment in the sun. Rich, your expertise is the hot ticket right now, in the overall guidance before we dive into the to the questions.

Dr. Richard Corsi

No, I think everything that Ms. Nahid said is absolutely right on. I would add to it that it’s important that everybody wear a mask because we don’t know who the effectors are. And we want to make sure that those that are asymptomatic in factors are also wearing a mask to reduce the total volume emissions of particles from their respiratory system. Improve ventilation where possible, you know, in parts of the country and Minnesota and that kind of thing. It’s hard to bring a lot more outdoor air in in the wintertime. But if possible, improve ventilation, portable air cleaners where you can’t increase ventilation or even if you can increase ventilation good HEPA Base portable air cleaners can substantially remove background aerosol particles in the air that might be the rideshare conveyor for this Corona Virus. So all of those things added to what Nahid said, I think keeps us all safer. You know, nothing is completely safe, but we can dramatically reduce our inhalation dose, which dramatically reduces our risk of infection.

Andy Slavitt

Got it. Okay, let’s dive into the questions. And Lana will chime in with questions follow ups to along the way. Our first question comes from Jeff Cavanaugh, Jeff says, we’re concerned about aerosols indoors. How long does it take particles this small to settle? Rich, Do you want to take a shot at that?

Dr. Richard Corsi

Yeah, sure. So we talked about aerosol particles, we’re talking about a pretty wide range of diameters of particles. So let’s say let’s start with a one-micron particle, a one-micron particle has a volume that’s about 1000 times bigger than the virus itself. And the viruses are conveyed in particles like one-micron particles and up. If we release a one-micron particle from 1.5 meters above the floor, so sort of halfway to the ceiling height, it’ll take about 14 hours to settle it using, you know, basic theory,

Andy Slavitt  08:19

14 hours to hit the ground?

Dr. Richard Corsi

14 hours on average to hit the ground, right. And so at typical indoor air speeds of, say, five to 15 centimeters per second, which is a typical range, I’ll just pick 10 centimeters per second, in 14 hours, a one-micron particle will travel about five kilometers before settling. So particles that size stay suspended, usually, for the entire time that air is inside of a building, if you go to a five-micron particle, it takes about 33 minutes to settle. And it can travel with those air speeds of about six to about 650 feet. So even a five-micron particle can travel long distances, 10-micron particles, about eight minutes to settle, typical indoor air speed 650 feet, you have to get up to, you know, sort of 50-micron particles and above, where you see settling on the order of 10s of seconds and travel times of you know, maybe six to seven to eight feet.

Andy Slavitt

So what are we typically dealing with here? What are the what are the typical particles that people would find when walking into a room indoors.

Dr. Richard Corsi

So in terms of particles that come out of the human body, if you look at the distribution of particles, the particle size distributions that come out of the mouth of somebody who’s speaking or who’s coughing, we’re typically talking about thousands of times more small particles to stay suspended in air, then larger particles that are going to settle very, very quickly. I’ve done analyses and mathematical modeling with everything I can find in the literature on speaking size distributions and cost size distributions. And in terms of total volume of particles, which really matters in terms of what deposits in our respiratory system. That kind of peak or the mode is in the range of about 1.5 to three-micron particles. When you when you when you take those particle size distributions and you convert them into volume by looking at volumes of vintage individual particles and summing them up. So that’s kind of the size we worry about in terms of background aerosol particles in the air. But also, if you’re in close contact with somebody very concentrated aerosol particles in close contact with an infector.

Lana Slavitt  10:21

These larger particles, these are the ones that we refer to as droplets, right? And the smaller ones are the aerosols.

Dr. Richard Corsi

Correct. I think that term that a lot of people using our ballistic droplets for these large particles that settle out within about five or six feet?

Dr. Nahid Bhadelia

Yeah, I was gonna add to what rich said, because when you walk into a room, right it’s from someone who’s looking at it from the healthcare worker perspective, when you walk into a room, I think, whether or not so there’s a person in that room who’s infected, right, and the more people that are in that room, the more chances there are that one of them might be in that room and they’re infected. And the elements that affect your ability to get sick, is that person is in, how many people there are, that are spewing a virus into the environment, how much virus are they carrying? So what part of their illness are they in, and we know that with this disease is a couple of days before you begin to you know, become symptomatic, if you’re going to become symptomatic, and a few days after that you have the most amount of virus or viral load. And the third is, you know, the ventilation as Rich said, which is I’m so glad we’re talking to him today. Because it is that ventilation and the ability to sort of clear the air or exchange the air in the environment that that makes your chances of getting sick when you’re in that space.

Dr. Nahid Bhadelia

And of course, your own, you know, ability to protect yourself, which is includes the mask, the last bit is the activity, which is why I think in the healthcare setting, we’re particularly worried because when we do certain procedures, such as when we you know intubate somebody placed them on mechanical ventilation, or we give them give them medications that are nebulized that you know, have those aerosols medications that creates generates artificially even more of a smaller of aerosols. So those are, those are ones they stick and stick around longer, which makes it much so much more important to have rooms that have that kind of circulation.

Dr. Richard Corsi  12:05

I was going to add one thing, because I’m glad that Nahid brought up activity because, we also oftentimes miss the fact that the respiratory minute volume, you know, the volume of air that we take in and exhale can be quite a bit different if we’re in a gym, doing aerobic exercise. And if we’re sitting on our couch watching television, right? You can have 10 to 15-fold differences in respiratory minute volume, which is why any environment where there are people exercising, or doing spinning on bikes, or dancing, or any of any of those things, you’re going to have a tendency for the infectors to emit a lot more if they’re engaged in that activity, but also the receptors to inhale a lot more. And so activity really does matter.

Andy Slavitt

I see you’ve seen me dance before. So you’re gonna give your mom a rule of thumb is it don’t enter in into a room you haven’t been in before? If you know people have been in there, wait one hour, where I’m asked, what’s the so what of this?

Dr. Richard Corsi

You know, waiting one hour, before going into a space that there may have been infectors in. That’s not long enough if the space is not well ventilated. So if it’s a pretty tight space with low air exchange rates, there’s no filtration going on. You know, the time could be more like three or four or five hours.

Andy Slavitt

Three or four hours.

Dr. Richard Corsi

Yeah. So at my university, we’ve designed to have a whole class period, empty between every class period, and we increase the ventilation rates. And we have improved filtration during that time. So we can get down to, you know, less than 5%, you know, on the order of two or 3% of aerosol particles in the air within about 90 minutes. But yeah, so the safest bet is too if you’re not sure about how much air exchange, there isn’t a space, wait a few hours.

Lana Slavitt

Is there a role for CO2 meters and things like this, you know, for lay people who don’t have access to the kind of professional tools that people like you do to measure air quality?

Dr. Richard Corsi

Sure, so there isn’t a specific cutoff. Normally, we say we want CO2 levels in buildings to not be more than 700 parts per million above background. But that’s normal, not in pandemic times. And that’s mostly to clear body odors, and that kind of thing out of the building. In pandemic times, we want that difference between indoors and outdoors to be much lower. There’s this concept called Rebreathe Fraction, which is the indoor carbon dioxide concentration minus outdoors divided by the levels on our breath. What that tells us is that Rebreathe Fraction is the fraction of other people’s breath in that space that we inhale, every time we inhale, right so if the rebury fraction is 5% that means every time you inhale 5% of the volume of air you’re inhaling came from other people’s mouths and that space or another way of looking at it is every 20 breaths is like walking lips with somebody and inhaling what comes out of their respiratory system. So we want that number to be as small as possible. General rule is sort of less than 1% Rebreathe Fraction and that’s going to be on the order of in the 700 part per million levels, so about, you know, 300 parts per million above background.

Andy Slavitt  15:06

Maybe we’ll put a link in the show notes to CO2 meters so people can use that as a rule of thumb, I will go to a question from Heidi [unclear]. And based on both of your expertise, we’re going to bounce around, feel free to free to chime in. If I asked a question to Rich, you know feel free to chime in and vice versa. The question is, do air purifiers help reduce risk when gathering indoors? If so, how do they compare to wearing masks indoors when socializing? Rich? Why don’t you start?

Dr. Richard Corsi

So, I think it’s important to distinguish between sort of two modes of aerosol particles. One is these background levels that accumulate away from an infector. I call that the indoor far field. And then there’s the aerosol particles when you’re in close contact with somebody which can be quite concentrated if they’re speaking at you, and you’re three feet away or something like that. So good HEPA based portable air cleaners, in the right scenario can dramatically reduce aerosol particles that are in that far field away from the infector they generally don’t help much if you’re in close contact and breathing the aerosol particles in close contact with somebody.

Andy Slavitt  16:11

While you’re both in the room together, you’re saying while you’re in the room with someone at the same time.

Dr. Richard Corsi

That’s right, mask will actually help with both, it’ll help with close reducing your exposure to aerosol particles in close contact, as well as background so and I would not put the two against each other just because you have a portable air cleaner in a room, continue to wear a mask because you get the benefits of both of them. And you don’t want to let your guard down.

Andy Slavitt

If you have a HEPA filter in there, does that reduce the amount of time before you’d have to when you’re comfortable entering a room, Rich?

Dr. Richard Corsi

It does, it can speed it up considerably. So a good HEPA portable air cleaner that has a cleaner delivery rate of 300 cubic feet per minute, typical say 600 square foot, apartment or room or classroom right? With a typical ceiling height is going to give you the equivalent of almost four air changes per hour sort of equivalent of how much clean outdoor air you bring in. So it can definitely speed up the time to get 95% reduction.

Dr. Nahid Bhadelia

I was gonna add to this question that Rich was posed about masks versus filtration. In health care, we’ve used HEPA filters in airborne rooms, right for a long period of time. So part of my day job is I run a bio containment care unit that’s designed to take care of patients with highly communicable diseases. And so we have like a double HEPA filter, and our Special Pathogens Unit. I would never allow any of my healthcare workers to go in there without a mask on. Because I think those two things work together. There’s the physics of this, but then there’s also the biology of it, which is that we don’t know what the minimum infectious doses. We haven’t figured that out with SARS-CoV-2. And even if it did, it seems like the dose matters probably because it matters in most patients, right? And most viruses. So the more the higher the dose of virus you get, the more likely you are to get sick. So when you reduce that dose, most likely your severity might go down in  SARS-Covid-2 or COVID-19, the virus that causes COVID-19. There’s also the we just still figuring it out. And it seems that it’s not just the dosage, it’s probably the propensity of the individual themselves, you know, their, their particular genes, their immune response ability to, you know, respond either maladaptively or well to the infection, so you can’t,  everybody’s risk is slightly different. And even if you have the same dose, it’s what I think we’re gonna end up finding out all of that to say, what those two as Rich says, underscoring underlining that work together.

Andy Slavitt  18:33

Got it. Okay, we’ll go to the third question. Okay, are there any forms of the variety of hybrid outdoor indoor dining arrangements? tents, open doors, canopies, etc, that are safer, or not that others?

Dr. Nahid Bhadelia

Yeah, I mean, I think in general, outdoors is always going to be better, right? Than indoors, partly because you you’re having to take that mask off when you’re eating, you can’t, we haven’t yet figured out how to eat with the masks on so you’ll be letting down one barrier and your swiss cheese model of how you protect yourself and so outdoors does make it easier of an athlete to rich in terms of the mechanics of how you allow that through air through to ensure that there’s enough ventilation.

Andy Slavitt

Nahid, do you consider an outdoor tent that’s covered on all four sides? [unclear]

Dr. Nahid Bhadelia

Oh my goodness, no, I consider that indoors. I saw that photo on Twitter about New York, you know, city restaurants setting up these little igloos of tents where people would just pack in this concentrating the air inside with everybody. They’re having their masks off. And it just gave me an anxiety attack. So no, I would not consider that.

Andy Slavitt

We have to teach common sense too; you can’t tell us everything.

Lana Slavitt

We have them all over Minnesota to these cold rooms, which are just basically like white plastic rooms outdoors.

Dr. Nahid Bhadelia

I’ve been wondering one wonders what’s happening is everybody who’s walking into those tents are they all part of the same household and so they all take they’re mask off. And then when they leave, do they undo and take down the entire tent? So there’s no you know, there’s a dispersion of all the aerosols and the droplets inside, I don’t know what’s actually happening. My guess is they’re leaving it up. And when you walk in, you know, it’s nice and toasty with everybody else’s aerosols in there from right before you.

Andy Slavitt  20:16

Yeah, my observation, and I didn’t feel this way in the spring is that if a governor or a restaurant allows people to do something, there are a whole slew of people that will just assume it’s safe. So if you set up a tent, and there’s, you know, 80 people in there breathing, just as you said, people will say, Oh, they wouldn’t have set it up this way. If it wasn’t legitimate, and the fact is, that’s not the case. We have to we have to kind of bring our own rules and judgment is we’ve had a lot of questions. So let me try to get to the next one, Enriching go back and add anything, of course. So is the infectiousness of either flu or COVID increased or decreased because of the two diseases occurring at the same time?

Dr. Nahid Bhadelia

Correct me if I’m wrong, I think the question probably doesn’t talk about infectiousness, but they mean severity is what my interpretation of that question was that does, does having both the flu and having COVID make your chances of having a more severe disease more likely, and the..

Andy Slavitt

The question was infectiousness, but you can answer both.

Dr. Nahid Bhadelia

Yeah, we don’t have so for the first part, there isn’t as much data on infectiousness, I don’t know that if you have if you have Influenza, it makes it much more likely, if you have COVID together makes you more likely to transmit that. I mean, well, there’s technicalities about that I won’t get into a geek out about but the severity part of this we do have a bit more clear, you know, understanding of there was a there’s a study from UK that was published in the British Medical Journal that actually looked at co infections of influenza and COVID-19, and showed that those that had both the odds ratio dying was 2.3 times higher in those that were infected with both compared to people who just had Influenza,

Andy Slavitt

Yo!

Lana Slavitt

It’s super important to get your flu shot this year, Andy.

Andy Slavitt  22:00

Get your flu shots. 2.3 times likelihood.

Dr. Nahid Bhadelia

And here’s the other part, the thing that is my secret fear that I’m keeping inside and we don’t have much yet data on is that when you survive, there is evidence that when you survive COVID-19, even if you have milder disease, that you have some sort of remnants on your body to stay on, right, we call this long COVID. But there’s evidence of it, you know, for people with moderate to severe disease that you leave scarring, a lot of really, you know, severe infections tend to leave the scar in for at least for a short period of time. And so my concern is what we know about influenza, as it’s like, it’s a cockroach, it takes advantage of like change in architecture and your lungs. You know, if you have someone with bad lungs to begin with, if you have COPD, if you have some other reasons why architecture is not perfect, you’re likely have more severe influenza, so it makes sense. So I worry about people who have survived COVID and their risk of having more severe influenza as well. And we haven’t yet figured that out. We haven’t seen that. But it would it would make sense if we found that.

Andy Slavitt

Okay, so you’re telling us flu is more dangerous? If you had COVID before, that’s very.. Rich do you have something to add?

Dr. Richard Corsi

Yeah, I was just gonna say all the things that Nahid and I have already said about everybody wearing masks, distancing, improved ventilation, hand hygiene, all of those sorts of layers of risk reduction will help with both, right. So hopefully, if everybody does the right thing, we lower not only our risk of becoming infected due to COVID-19, but also a risk of becoming infected by Influenza.

Dr. Nahid Bhadelia

Yeah, and that’s actually already proven. I know, you know, I’ve had to go back because when I first read this, I couldn’t even believe it. But the Southern Hemisphere is experienced right now with Influenza. I mean, it’s so drastic, like, if you look at Australia, Chile and South Africa, you know in 2019, 13.7% of their samples are positive. So they’re test positivity, if you will, for flu was 13.7%. Guess what it is this year with the summer, you know, with all the mitigation measures is  .06%. So it’s really driven down the Influenza transmissions as well. And one hopes, one hopes are experiences similar to theirs. We don’t know what our season will look like, right? And we don’t know how good people will be.

Andy Slavitt  24:14

When is the official start and stop with the season.

Dr. Nahid Bhadelia

So we’re already seeing Influence activity. It’s not very high. But they’re already influencing cases here in the United States. The numbers of sort of..

Andy Slavitt

When’s it over?

Dr. Nahid Bhadelia

Every year is slightly different. But generally, you would say about, you know, March or April, but again, it depends on the year and depending on when it says test translating. So, get your flu shot.

Andy Slavitt

And now for something we like to call advertising.

Andy Slavitt

So it’s almost Thanksgiving. And we have a question from Jane Anderson. Is there any safe way to get together with family this year, or should we wait until spring or gather together, my family’s small, the three of us are high risk and two of us can’t isolate beforehand. Rich, do you want to start?

Dr. Richard Corsi

Sure, it sounds like a difficult situation to me, right. So you know, if anybody is been in contact with somebody who’s infected or is quarantined, they should definitely not get together with family. And if there are those that are high risk in a family, compromised immune system, elderly, you know, those with diabetes, etc, I would seriously think about taking a pass this year, so that you can be alive to celebrate with your family, you know, next year. But you know, if families are going to get together independent of making those hard decisions of not being with family at a special time of year, you know, all the things we’ve talked about already, you know, having everybody in the family and they’re getting everybody wear masks when they’re indoors together, distancing from one another have a voice etiquette in the family. So people aren’t singing or yelling. In an indoor space where they’re emitting a lot more particles increase ventilations.

Andy Slavitt  26:03

Sorry we can’t do that.

Andy Slavitt

All right, you know, all the things we’ve talked about just layers and layers of dose reduction leading to risk reduction is important.

Lana Slavitt

Maybe do it outdoors.

Dr. Richard Corsi

Yeah.

Andy Slavitt 

Here’s what I’m worrying about. I’m worrying that guidance is so confusing. And people are trying to make it simple for themselves, that people will think they can get together for Thanksgiving. And as long as they’re six feet apart at the table, as long as they space out their chairs, that they will be fine. Even though they can’t possibly know even if they don’t know that everyone in the room is healthy that it feels to me like that’s a mistake we are setting ourselves up for.

Lana Slavitt 

Just to tag on to that in Minnesota, you know, the State has advised that you should restrict gathering sizes to 10. But you know, 10, could be five households. And that just feels crazy to me.

Dr. Nahid Bhadelia

Yeah, the way the CDC lays it out on their website, right, they first talk about the community transmission as a basic risk factor. And as I just said, at the beginning of this, I mean, I think we’re getting to a point where most of our communities are going to end up being in high risk areas. The second is reducing the number of people who are coming out of your location, you know, if there are people within your own location that reduces their risks from actually traveling and, you know, there might be coming from a higher risk community, then the new but to the act of travel itself and potential exposures that might happen along the way. Also the other elements of it. So all these layers, right, one is leaving it, the safest thing is here is to have a small Thanksgiving dinner with only people who are currently in your household, or maybe a couple of more people but having it outdoors at a distance, right?

And that that might reduce the reducer the risk as well. But all those layers of mitigation that you know, we’re talking about, like the making sure what your listener just said, making sure you quarantine beforehand, which basically goes to reducing all the possible exposures you might have, so that you’re reducing your chances of bringing the disease home, others may have said, you know, adding a layer of testing and they’re potentially getting tested knowing that, you know, a lot of the tests that we have on the market right now are not as accurate and people who are not symptomatic. So it may not be 100 proof, even if you end up being negative. Third is protecting yourself when you travel. So you put on that personal protective equipment, you do everything you can when you’re traveling to ensure that you’re not going to get exposed to people.

28:24

And then when you get back to your home or wherever you’re going, whether it’s your Thanksgiving dinner, potentially getting either tested again, or using masks while you can while you’re indoors, think about all the steps that those are and the number of people if you increase the number of people who are coming into your household, you’re increasing the chances that someone skips a step misses a step, and there’s an increased risk. And that’s why reducing the number of people gathered at any one time, I think is the one of the biggest modifying risks that you could do.

Andy Slavitt

Got it, so small smaller crowds helps. And then you referred earlier to what you called the Swiss Cheese. And I think it’s a great analogy. And I’m not sure everybody’s heard it. But you just sort of described it. Can you just in a second, describe what you mean by Swiss Cheese and how even with a vaccine, how that’s still an important concept.

Dr. Nahid Bhadelia

The Swiss cheese model is you know, we use this in healthcare all the time the idea that errors occur. So the way you sort of keep an error from becoming a disaster is because you have all these different mitigation measures, you know, all these steps that like Swiss Cheese, the holes are in different places, every one of these strategies could fail, you know, but for all of them to fail together, all the holes will have to align. And so it makes it much, much less likely if you have a system that has all these different mitigation measures so that even if one fails, something else will catch something that’s an error, keep it from becoming a disaster.

Dr. Nahid Bhadelia

So it becomes an issue because you know, even if we have we don’t know when we have a vaccine, how effective the vaccine is going to be. We don’t know if people who get the vaccine might really still have reinfections even if they don’t end up having disease again, right? They may just get the infection have the virus in their airways, we don’t know what their ability to transmit is, it’s always going to be the case that we have to until we get to a point where we have good enough vaccines and enough people vaccinated and build this vaccine induced herd immunity that we have to take those measures, all those measures, including masking, reducing the number of people ventilation.

Andy Slavitt  30:20

So we’ll put a link up to an image of the Swiss Cheese for people to download. I think it’s very common sense. And I think it really helps people understand how the layers   help, Rich?

Dr. Richard Corsi

Yeah, I just want to add, I’ve been doing a lot of mathematical modeling for all sorts of different building environments, from classrooms, to mass transit to homes to gyms and restaurants, etc. Using the approach that Nahid just outlined, and doing this layered dose reduction strategy, I call it, we can easily in many environments get a 95% reduction in dose. And it doesn’t necessarily cost a lot of money or involve really complicated technologies. So we should be striving to have those kinds of levels of dose reduction 95% is a 20-fold, you know, 20-time reduction in the amount of dose in an indoor environment. Who wouldn’t want that? I mean that he is going to lead to risk of infection reduction as well.

Lana Slavitt 

Can I ask a question? Is there a role for fans if the windows aren’t open, or if there’s not ventilation, I see people putting fans on all the time and enclosed spaces, and it just feels to me like they might just be like spreading the virus around.

Dr. Richard Corsi

So if you can put a fan a box fan in a window, if you could open the window, you’re going to you can control and get much higher ventilation, if you’re blowing in with the box fan in terms of windows being closed and using the fan. What that does is it mixes the indoor environment. And at the indoor environment has a say a large volume and you want to get good vertical mixing, which essentially disperses and lowers the levels of aerosol particles in the air, say in a grocery store or in any room that has a large volume, it can actually be pretty effective for lowering the concentrations and the breathing zones and where people are near the floor. So in that case, good vertical mixing helps. If you happen to be in close contact with an infector, a fan can be pretty good at giving you some cross flow that disperses aerosol particles away from your breathing zone. The problem is you don’t know who the infector is. So it’s hard to say I’m going to place a fan right here because that’s where the infector is going to be. So in that case, it’s not very, very valuable. But good vertical mixing, especially if you have a large volume will help in terms of lowering the particle concentrations in your breathing zone.

Andy Slavitt  32:38

Maybe he catch us up on the state of testing and some of the various test, is it more important to know whether or not you’re positive or whether you’re positive and infectious? And given that is, are these tests actually? Does that help describe the accuracy of the saliva or the by next?

Dr. Nahid Bhadelia

So that actually the question that you asked comes up a little bit more about the Antigen versus the PCR test. Right. So the trouble with is PCR does it Andy, as you just said is that many of them stay positive for a very long period of time, but they might just be you know, shedding dead virus. So we don’t know, whether they’re useful or not, the question now is come up with these Antigen tests, these new types of tests where you actually detecting a particle of the virus itself, not the genetic material, but some particle of the virus. And so these tests tend to be, you know, positive around the same time, like the couple of days right before someone becomes symptomatic, if they’re likely to get symptomatic. And within the first seven days is when the FDA says of the Rapid Antigen test that they have out those are the that’s the period of time you could use it at the total antigen test is that they help you when they’re positive, because their specificity tends to be pretty good.

Dr. Nahid Bhadelia

And generally, you know, they’re useful when someone’s symptomatic, and they turn out to be positive way to go, you know, if they’re someone’s asymptomatic, and they tested and they came out to be positive way to go that that helps too. Because you know that you know, this person is positive, it becomes harder, because if someone is symptomatic, and they end up being not positive on the antigen test, you might still want to follow it up with a PCR because it’s not as accurate. And if someone’s comes back in their pot in there, and they’re asymptomatic and they’re negative, then you may want to follow it with a PCR because we know that these tests don’t tend to be as accurate and people who are asymptomatic all this to say that if you’re planning to do a Rapid Antigen test to go to Thanksgiving, it’s not this one step, but it’s not going to guarantee you’re not taking the disease home.

Andy Slavitt  34:24

The Swiss Cheese holes are a little bit bigger. How long do we think based on what we know, today, people are infectious for because we know people test positive much longer than that. But is it? Is it 10 days? Is it two weeks? What’s the latest thinking?

Dr. Nahid Bhadelia

So for people with mild to moderate disease, the CDC says about 10 days is what they  asked the isolation period to be, and people who are sick for longer who might be severely sick. the shedding of the virus may go on for live hours may go on for longer, but even then, there was a nice meta-analysis that showed that 14 days the chances that someone might be shedding live virus goes down below 5%.

Andy Slavitt

Okay.

Dr. Nahid Bhadelia

But the CDC guidance is 20 days if you’ve been severely ill you should be isolated from for 20 days from your on-symptom onset or first positive test.

Andy Slavitt

Got it. Okay. I think we got a couple more questions here left, but Lana, I want to check and see if there’s anything that you think are big things we haven’t talked about yet.

Lana Slavitt

Oh, actually, you know, I did have one, we haven’t talked as much about the time spent in any space. So you can, you know, reduce your exposure to virus, you know, aerosols by wearing a mask by ventilation. But, you know, there’s also a role, I think, for how long you’re in a space. So like, I can do my grocery shopping in under 15 minutes now. I mean, I have a plan, I know exactly where I’m going to start, I know, I’m going to check myself out, I’m not going to build an entire cart and buying what I need. And I’m out of there, because I have no idea how well ventilated my 1960s grocery store is.

Dr. Richard Corsi

Yeah, I mean, your examples, a great example. So inhaled dose is equal to the amount of stuff that’s in the air, the number of particles or the number of Baryons per liter of air, multiplied by your breathing rate, which are the respiratory minute volume, multiplied by the time that you’re in that environment, breathing this stuff, so you can reduce your dose by reducing any of those. And the one thing there that we have complete control over is the time we spent an environment. So I say this all the time to people is that if you’re going to a grocery store, have a checklist, get the items get out as quickly as possible. Don’t wander up and down the aisles thinking about what you might want to buy this week or next week. In and out, whether it’s a pharmacy, a grocery store, you know, a gas station, whatever it is, you know, limit the amount of time you spend in that indoor environment, any environment other than your own home, you should limit the amount of time you spend in and you should be wearing a mask and everybody else in that environment should be wearing a mask.

Andy Slavitt  36:55

Don’t go anywhere, we’ve got to go earn some money to donate to charity.

Andy Slavitt

Okay, a couple more things, just maybe some technical things here humidifiers, Rich, do they help? One of the questions we had was whether or not a humidifier will help, particularly if there’s someone who happens to be test positive.

Dr. Richard Corsi

Wow. So if somebody has tested positive, you should set up an isolation zone in your house, if they are isolating at home and put that zone under negative pressure, just like you would do in an isolation room in a hospital. The way you do that is to you know, put a box fan in a window if you can, and just blow the air out, not in but blow it out. And that’ll cause the air in the home to sort of go towards that space and not out of that space back into the entire house. In terms of humidifiers, it’s a tricky question, right. So there is some data now there are some data that suggests that at lower temperatures and lower relative humidity’s indoors, the virus can stay it’s inactivation rate is not as rapid in aerosols, but even under the good conditions for the for us or bad conditions for the virus kind of in the sweet spot where the inactivation rate is the highest, the half-life is still on the order of an hour or more depending upon a couple of studies.

Dr. Richard Corsi  38:20

So it’s not going to change. Changing humidity is not going to change the sort of infectiousness of the particles in the air that much, right? It may on surfaces in terms of how long viruses stay viable on surfaces, lower relative humidity does cause the volatile fraction of particles that come out of your mouth to shrink, right. So what that does is it can take some particles that maybe would have deposited sooner on surfaces and shrink them down to sizes where they stay suspended longer, which is not a good thing from an inhalation standpoint. But it’s not easy to say that adjusting relative humidity is going to have a dramatic impact in terms of safety at this point.

Lana Slavitt

So you mentioned the box fan in the window. I haven’t heard that before in terms of creating negative pressure. What about sealing off the heating and air ducts in those rooms? Just putting plastic over them or something?

Dr. Richard Corsi

Yeah, I mean, you so you can do that too, especially the return ducks are so that the air in that room doesn’t get sucked back to the centralized HVAC system that then distributes throughout the house. Yeah, so but putting it under negative pressure is the most the most important thing.

Andy Slavitt

So there’s a question from Steve Turner, about MERV 13 air filters and maybe you could actually explain what those are and give us your point of view on those.

Dr. Richard Corsi

So MERV stands for Minimum Efficiency Removal Value, MERV. It’s a standard test that’s done to classify filters. So typically, people have in their homes filters that are lower than MERV 13, quite often it’s MERV 4, MERV 6, MERV 8, those kinds of classifications moving to MERV 13, if it’s properly seated in the mechanical system, and that’s really important if it’s properly seated, and if your mechanical system can handle having a Merv 13 filter in it, it can dramatically reduce when it’s operating dramatically remove most of the particles of the size we’re interested in that are the rideshare, or the conveyors of, of the SARS-CoV-2 virus. Not every system can handle a Merv 13 filter. And that’s important in our university, we replaced all MERV 8 filters with MERV 13, filters in 90% of our buildings, the other 10% couldn’t handle it. And so we essentially took all the classrooms in those buildings offline. So you have to make sure that your system can handle a MERV 13. And if it can, then it can do a really good job at removing particles of the size that we worry about.

Lana Slavitt  40:58

Do you check with your HVAC service people? Is that who would know?

Dr. Richard Corsi

You could check with your HVAC service people. That’s right.

Andy Slavitt

Okay, so let me let me close out with a couple questions for each of you. And by the way, which you’ve written some great pieces that we will link to, because I know a lot of these things are hard to remember, for people. And so we’ll make sure that if you can get lost between 400 700, 15, and 13. And all these things, I just know that during SARS, I turn my amp up to 11. And then I’m okay. Let’s close, let me just start by asking you both step back a little bit. Think about the next three or four months, people have a lot of anxiety about winter. They’re the people that are going to be lonely, like, and then they’re going to want to make sure to check in on them. And of course, they’re worried because as you both said, we’re in a particularly frightful time for the virus. What are we missing? What other general things did we not cover that the you’d want to remind people of?

Dr. Richard Corsi

You know, I think you know, you’ve alluded to the mental health aspects of this pandemic. And I think that’s really, really important. I’m a gym rat, I used to go to the gym six nights a week for about 90 minutes every night, and in late February, I stopped going. And that’s affected me, that was my way of winding down from a hard day. And  I’ve been struggling with that is how to how to wind down at the end of tough days. And everybody has their own problems they have to deal with. But I think the mental aspects of this are important, the one thing we didn’t address and the one thing that I think’s been missing, from all of discussions during the pandemic is how to properly communicate with the general public. There are communication scientists that do research on this, spend their entire careers on this that understand that people absorb information, different people absorb information in different ways. Some learn from reading some learn from watching television, some learn from friends that they trust, some learn from visualization. We’re not a monolith in terms of we how we absorb information. And I think bringing that field in communication science into all of this and helping to understand how to best communicate using almost layered communication systems instead of layer risk reduction systems, right? To try to reach as many people as possible is important in that aspect of this pandemic, I feel has been woefully missing.

Andy Slavitt

Not only that, I think we’ve had people who have been putting misinformation out, or irresponsible use of information. And I think that’s very confusing for people. If you haven’t listened to the conversation I had with Ed Yong from the Atlantic, we talked about how our brains conceptually, don’t instinctually take us to the right place when thinking about how a virus works, that some of these things have to be to be learned and ingrained into us some of the things you’re telling us because we don’t think about how things linger in the air. We don’t think about how things grow exponentially. We don’t think about looking at someone who feels perfectly healthy, as he was saying and thinking that they can be dangerous. We don’t think about needing to wear masks when that when we’re feeling well. And there are some really, in fact, I may have him on the show. It’s Baruch Fischhoff at Carnegie Mellon. There are some really kind of almost nasty hierarchies that people use to make decisions.

44:21

And a lot of it, it’s stuff that if you don’t know, even if you’re well intended, your communication leads to the wrong place. And so there’s a whole bunch of these kind of very complex reinforcing things about how people hear information that lead us to be even more suspicious and so forth of the information we hear. So someone goes into a room, right and follows your advice Rich, and they get COVID. They’ll walk out saying this guy didn’t know what he was talking about. And if they don’t get COVID they’ll say, well, what Rich said was obvious. We knew that already. That’s the way the human mind works. That’s not anybody discounting your expertise. That’s just how our minds tend to work.

Dr. Nahid Bhadelia 

Yeah. I am, I’m going to add to an echo what you and Rich both said, because I kind of feel that mentioned the elephant in the room, which is the CDC does have all those experts on communications around public health, and we utilize them a lot during Ebola in particularly with an evolving condition then, and we haven’t heard from a lot of those CDC scientists, and in my view, what that’s done, its creed, the creed, you know, in generally, even if you don’t agree with everything a public authority says, you know, there’s a recognized public health voice and the CDC has often been that voice for us. And there are laws, you know, more or less easily accessible, you know, part of this that we had with the CDC scientists not having that creative vacuum. And that vacuum shattered into hundreds of citizen scientists, medical professionals trying to help out. And it also created space for malicious actors. And that space is what’s created this confusion. It’s not just that it’s a confusing situation, we made it 100 times worse, because we lost that beacon.

Andy Slavitt

Is that because there was an elephant in the room instead of a donkey in the room?

Dr. Nahid Bhadelia

I guess we’ll find out.

Andy Slavitt  46:12

That’s a little political joke. Last question, I want to ask a special question of each of you. And I probably should have done this in the beginning. But tell us about your work. Tell us about what your days have been like, and maybe a story from what you’ve witnessed that will really help people kind of get some of the tacit feel for what you’ve been dealing with.

Dr. Nahid Bhadelia 

Yeah, Andy. So the majority of my work is I backed up, I run this medical unit that backs up a maximum containment laboratory where we do BSL-4, you know, Viral Hemorrhagic Fever Culture Research. And so I run the Medical program that backs that up, that includes running this bio containment unit. And because of that, I’ve been involved with viral hemorrhagic fever responses in the past, and have been working, you know, internationally in Liberia and Uganda. And it’s funny because I was traveling back to the US in February after one of those trips, as my hospital was trying to prepare for this. And there’s so many echoes on that, you know, there were things that happen from my prior experiences in West Africa, where you could say, well, how could this happen in a resource rich country, you know, things like we had to use personal protective equipment, things where we had to employ crisis standard of care choosing between patients.

Dr. Nahid Bhadelia

And when we, as I’ve lived through this pandemic, as a healthcare worker, now in the richest one of the richest countries in the world, it breaks me to see that there isn’t a single hospital that I know, that’s not reusing N95. And it breaks me because I was in Sierra Leone, one of the poorest countries in the world. And, you know, we were having to make this decision about what we do when we can’t get personal protective equipment. And it breaks me that we knew how to do this better. And we’re at a point where there are doctors and nurses and respiratory therapists who are making these types of decisions about who lives and who dies in parts of our own country who didn’t have to make those choices, because we could have mitigated this, this risks these cases could have been lower than where they are, this was a hazard and we turned it into a disaster because our response to it was not as robust. Not as committed, not as consistent, and not as proactive as it should have been.

Andy Slavitt  48:25

Nahid, could I just say that the earth is lucky to have you.

Dr. Nahid Bhadelia

I don’t know if the earth always feels that way.

Andy Slavitt

Thank you for all you do. Rich, My question for you. What do you like to play on that guitar?

Dr. Richard Corsi 

Oh, thanks for asking. So I write a lot of my own music. And I record a lot of my own songs that very few people have ever heard

Andy Slavitt  48:47

Go grab it.

Dr. Richard Corsi 

I can’t

Andy Slavitt 

Come on.

Dr. Richard Corsi

No, no, no, the stage fright is way the activation energy for that is waste.

Andy Slavitt 

Just a few, just a few.

Dr. Richard Corsi 

Really?

Dr. Richard Corsi 

Oh, my goodness. I have very sweaty palms right now.

Andy Slavitt 

Yeah.

Andy Slavitt 

This is great. Take it away.

Dr. Richard Corsi 

That a little bit.

Andy Slavitt 

Beautiful. It’s a wonderful way to end the show. But still, I think to sum up, where indoors have well ventilated rooms. You can measure the CO2 if you’re not sure. There’s everything from filters to Windows if used properly, but we should just all take great care while we’re indoors and particularly if we’re bringing a lot of people in I can’t thank you guys both enough. There’s some of these shows what I learned way more than I expect to and this is one of those shows.

Dr. Richard Corsi 

Thank you, Andy.

Dr. Nahid Bhadelia 

Thank you, Andy and Lana. Thank you, Lana.

Dr. Richard Corsi 

Yeah, thank you, Lana. Everybody.

Lana Slavitt

Thanks a bunch.

Andy Slavitt

That was great. And I have to tell you that I just thought I said this guitar behind him. And I was just I was just asking, and he was so gracious to play for us. It was clear he didn’t want to and, and I felt a little bit like I talked him into it. But I can tell you, there’s something about music and moments like this that lifts your spirits. And it was very touching, I think to watch him do this. And I’m so grateful for the contribution that he made all of us. And well, both of them are there. They’re both phenomenal. I have zero musical talent, so kind of envious of people who do. Let me tell you about the next few shows we have coming up? They are. They’re great shows. I’m really excited about it, to be honest. Wednesday, Eric Topol phenomenal scientist, who is probably one of the most prolific scientists who has been focusing on the pandemic, the scientific elements, the political elements, all of it, he has a kindred spirit, you’re gonna love that episode.

Following, we will be talking about the transition to the next president. So that will be a fun show. And we’re aiming for some really great guests. And then finally, the next Wednesday or Third show out Tom Inglesby. Tom Inglesby is kind of the, this isn’t the exact title, but he’s a senior epidemiologist at Johns Hopkins, which has been the leading firm and telling us what’s going on with this virus. He’s one of the people that I think is the original sources of everything. He’s great. So between those three episodes, we should be doing all these episodes, we should hopefully be getting you some of the information that you need. I really hope you’re doing okay out there. I think about all you guys all the time. And I hope that you’re getting through things and we’re gonna make it through. Thanks for sticking with me. Bye.

CREDITS

Thanks for listening IN THE BUBBLE. Hope you rate us highly. We’re a production of Lemonada Media. Kryssy Pease and Alex McOwen produced the show. Our mix is by Ivan Kuraev. My son Zach Slavitt, is emeritus co-host and onsite producer improved by the much better Lana Slavitt, my wife. Jessica Cordova Kramer and Stephanie Wittels Wachs still rule our lives and they executive produced the show. And our theme was composed by Dan Molad and overhill and additional music, but Ivan Kuraev. You can find out more about our show on social media at Lemonada Media. And you can find me at @aslavitt on Twitter, or at @andyslavitt on Instagram. If you like what you heard today, most importantly, please tell your friends to come listen, but still tell him at a distance or with a mask. And please stay safe, share some joy and we will get through this together. Hashtag stay home

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