How to Safely Open Your Office
Darius Lakdawalla outlines the value for universal screening for COVID-19, as well as the cost benefits and practical approach to pooled testing applied in businesses and schools. Richard Green asks questions regarding the challenge of children adopting masks, how evolving information impacts the public, and what Lakdawalla’s criteria would be for his children returning to school.
Please note this automated transcription may contain errors.
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Richard Green: So good morning everybody. My name is Richard green I'm director of the USC Lusk center for real estate and it's my pleasure to welcome you to the June 17 2020 edition of Lusk Perspectives.
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Richard Green: We have a great guest today Darius Lakdawalla Darius is a colleague of mine. He's on the faculty at the price School of Public Policy, as well as pharmacy school here at USC and
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Richard Green: Is a member of the fabulous team at the USC Schaeffer Center for Health Policy, I asked him to join us, because one is just extremely qualified and thinking about the economics of COVID. He's somebody who publishes in both economics and medical journals.
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Richard Green: And second, because he and his colleague and my colleague, Dana Goldman
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Richard Green: Are doing really interesting work on how to test in a matter that will allow us to safely reopen things that of course is an issue that's on a lot of people's minds right now. And so I am particularly wrote
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Richard Green: Read a summary of a paper that Indiana did on using pull testing as a method for inexpensively and rapidly knowing what places are safe to reopen. And so with that, Darius. Thank you very much for being here.
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Richard Green: One piece of housekeeping. If you have a question, please type it in the Q AMP a box and at the end of Darius his presentation I will forward your questions to him. So take it away your eyes.
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Darius Lakdawalla: Thank you Richard. It's great to be here and thanks for having me. Let me share my screen is or my slides visible now.
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Richard Green: Me, they are. Yes.
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Darius Lakdawalla: Great. Okay. Thank you.
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Darius Lakdawalla: As Richard mentioned, I want to talk a little bit about the issue of how to reopen schools and businesses in the, the value of this maybe is obvious, but I think it's worth reiterating the stakes of the game here that
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Darius Lakdawalla: In terms of value of reopening businesses, we are projected to lose roughly a trillion dollars of GDP per year got here or here on out as a result of covert related closures.
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Darius Lakdawalla: So bringing the economy back. I won't say to normal but closer towards normal is an important step and limited bleeding, so to speak, from our code related shutdowns, but at the same time, we can't do this in a way that compromises health because that has its own GP consequences.
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Darius Lakdawalla: In addition to reopening businesses. There's the I think rather pressing issue reopening schools. And here, the value of reopening schools is twofold.
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Darius Lakdawalla: For those of us who have school aged children who've been at home to this lockdown. We don't need peer reviewed studies to tell us this but
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Darius Lakdawalla: Children's Mental Health is has been compromised by covert related lockdowns. And actually there's quite a bit of evidence now that
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Darius Lakdawalla: About a quarter of kids in a variety of countries were different surveys studies have been fielded about a quarter of school aged children are exhibiting symptoms of anxiety and depression.
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Darius Lakdawalla: During coven related quarantine and lockdown. This has been true across China, the US Britain, Germany and a number of other countries.
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Darius Lakdawalla: The other issue is that as we shift the education from the school to the home. One of the consequences is that inequality rises and this is a
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Darius Lakdawalla: fairly familiar kind of problem when we move the lotus of education towards the family and away from of formal schooling that kids and more advantaged families will do better than kids and less advantaged families. And that's something we can ill afford
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Darius Lakdawalla: In an environment where the economy is already teetering and threatening the well being of some end of families are already at the Martin society.
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Darius Lakdawalla: So I wanted to begin with those points because I'm going to talk a lot about the challenges of reopening schools and businesses and it's helpful to keep our eye on the ball and thinking about
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Darius Lakdawalla: Why those challenges are actually worth struggling with. So let me turn to the question of how and and and in what fashion. The reopen businesses and schools.
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Darius Lakdawalla: What I'll do is I'll begin by talking about the need to universally screen asymptomatic people for covert in the context of other non screening strategies as well.
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Darius Lakdawalla: I'll talk a little bit about the work that Richard mentioned that we've been doing on quote unquote pooled testing.
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Darius Lakdawalla: For coven and then I'll conclude with some recommendations about how to implement these kinds of containment strategies and businesses and schools, just look. Let's begin with a few
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Darius Lakdawalla: With the with the dismal
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Darius Lakdawalla: Mathematics of coven spread that unfortunately what makes this disease, particularly problematic is that it spreads efficiently and through asymptomatic people
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Darius Lakdawalla: This is a bit of a controversial number, but most of the emerging evidence suggests that somewhere around a half or maybe even more of new coven 19 infections.
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Darius Lakdawalla: Were generated by a person who was not yet showing symptoms. There seems to be relatively efficient spread during the pre symptomatic phase. And this is actually a big difference between coven and other
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Darius Lakdawalla: Corona viruses in the past. One of the things that limited the spread of the SARS epidemic, for instance, is that SARS really only spread
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Darius Lakdawalla: In symptomatic phases. So it was relatively easy to contain
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Darius Lakdawalla: And people who are sick are just fundamentally less efficient it's spreading illness because they're not up on about and engaging in their daily lives. So this is what's one of the one of the unique factors of the illness. There were others as well.
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Darius Lakdawalla: And it poses a challenge for us and reopening schools and workplaces, because
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Darius Lakdawalla: As much as we'd like to rely on things like temperature checks and and questionnaires about. Have you been coughing or if you've been short of breath.
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Darius Lakdawalla: Those are not all that effective actually in detecting people who are harboring the illness and are able to spread the illness. The other issue, which is relevant for businesses and schools trying to reopen is that the overwhelming majority of infections occur indoors.
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Darius Lakdawalla: For instance, there was a study done by some scholars in Hong Kong, looking at Chinese data.
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Darius Lakdawalla: And have the, I mean, they looked at all the outbreak information they had at the time they had over 300 outbreaks to study and only one of them occurred outside
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Darius Lakdawalla: It was for a group of men in a village. We're talking over the course of 90 minutes and there was an infection transmitted
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Darius Lakdawalla: Japanese data tells a similar story that transmission is almost 20 times more likely indoors and outdoors. So this is a problem for businesses and schools.
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Darius Lakdawalla: Because we're going to have to figure out how to create safe indoor spaces, given the likelihood of asymptomatic spread
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Darius Lakdawalla: As this all comes down to the, the key point, which is that schools and businesses need to have a strategy for screening asymptomatic, and there's nothing wrong with having temperature screening
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Darius Lakdawalla: And other strategies for measuring symptoms, but it's not nearly a sufficient approached detecting infection.
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Darius Lakdawalla: Now, when we think about the goal here. The goal is not to eliminate the illness from your premises that's impossible, given the way this disease spreads. If there are outbreaks.
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Darius Lakdawalla: It's more likely than not that businesses and schools will have infected people
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Darius Lakdawalla: The question is, how do we prevent a small outbreak from becoming a big outbreak and there. There are several principles we have to think about here and this underlies
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Darius Lakdawalla: All of the social isolation controls and other strategies that have been proposed.
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Darius Lakdawalla: The first point is you've got to try to limit the contagiousness of the people who are harboring Neil. So this is the this is the rationale behind six feet apart masks.
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Darius Lakdawalla: Sanitation handwashing. One thing we do know, or we're beginning to see is that transmission is typically person to person and much less often person to surface, the person
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Darius Lakdawalla: So it's still important to practice hygiene and sanitation, but principally we're trying to limit the transmission of the illness directly from one sick person to another. And that's
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Darius Lakdawalla: Where distance masks and related strategies, come in. Another issue is bathrooms and this is not a pleasant subject, but the transmission of coven via
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Darius Lakdawalla: Via fecal transmission is is is now established as a as an important factor. So you want to make sure there's not a lot of congestion in bathrooms.
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Darius Lakdawalla: Some businesses, for instance, have shut down every other stall and their bathrooms are they've implemented controls regarding how many people can be in the bathroom at once. So these kinds of strategies will be important to limit contagious.
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Darius Lakdawalla: The other or another approaches that needs to be pursued in tandem with this is to limit the number of contacts per day. So what that means is if you have somebody who's, who's infected.
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Darius Lakdawalla: Yes. You want to make sure that if they come into contact with an infected person, it's less likely they spread the illness. That's where six feet apart comes in and mask.
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Darius Lakdawalla: But you also to the best of your ability. Want to make sure they don't run into a lot of uninfected people or people at all.
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Darius Lakdawalla: So this is why we want to limit the number of exposures or contacts in a given day for each person. And remember, you don't know who's infected. That's why.
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Darius Lakdawalla: These rules have to be applied across the board because of the problem that people who aren't exhibiting symptoms might be sick. So the way to reduce the number of contacts per day is pursuing
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Darius Lakdawalla: Cohort separation and remote work dates. For instance, a common strategy is to split up a student body or a workforce into groups of two, three or four
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Darius Lakdawalla: And on one day Group A might be in the office and Group B, C and D might be working at home, and so on. So, you reduce the number of people present
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Darius Lakdawalla: The other thing you do is you limit the number of people that you limit the number of contacts that any one person has, for instance, if you find someone who's sick and you know they're in Group A
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Darius Lakdawalla: While then you only have to quarantine people in group A, you can be reasonably confident that B, C and D. We're not also exposed
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Darius Lakdawalla: Similarly, you want to limit the number of days people spend in the workplace, while they're infected, and this is where remote work days also
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Darius Lakdawalla: Because if people are are coming into the office, less than five days a week.
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Darius Lakdawalla: It limits the number of opportunities for them to spread the illness. If this is also where testing matters. It's important to identify when people are sick so that you can take them out of
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Darius Lakdawalla: The workplace as quickly and efficiently as possible and trace all the other workers. They may have contacted
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Darius Lakdawalla: The final point is you want to try to limit the susceptibility of uninfected people. And I think the practical point here is some people are at greater risk.
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Darius Lakdawalla: For acquiring the illness and also getting very sick from meals. Those people need special protection people. We know that people with respiratory comorbidities like
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Darius Lakdawalla: chronic lung disease, for example, or asthma are at greater risk for complications.
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Darius Lakdawalla: It also appears to be the case that people with clotting disorders or stroke risk are at greater risk of complications because coven seems to interact in ways we don't quite understand.
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Darius Lakdawalla: On the cardiovascular system as well. Moreover, workers who live with, say, an elderly relative that has those kinds of conditions are
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Darius Lakdawalla: By extension themselves high risk workers. So you want to protect the family and the social network of workers as well. So in some sense, the question becomes,
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Darius Lakdawalla: How do we protect our most vulnerable individuals. And the answer might be. We have to take special steps to limit their exposure limit their days in the office, limit the number of people they come into contact with. And so
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Darius Lakdawalla: The other point here is that there's not going to be a one size fits all strategy for these social isolation controls that if you're running a small business without a lot of elbow room there's only so much you can do with six feet apart. Maybe their masks are critical.
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Darius Lakdawalla: If you're running a large warehouse.
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Darius Lakdawalla: Then six feet apart is relatively easy to accomplish and maybe you can get the eight feet apart. There's nothing magical about six feet apart. It's just a question of probabilities. So the more personal space.
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Darius Lakdawalla: You can achieve the better. But if he can achieve personal space. You've got to figure out other approaches.
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Darius Lakdawalla: One other approach that's important is if you can't separate people then you've got a test even more aggressively because you've got to make sure that you get sick people out of
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Darius Lakdawalla: The flow of exposure as quickly as possible. The other point here is, it doesn't make any sense to implement policies that nobody can or will comply with
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Darius Lakdawalla: So there's some things that are easy for a business to monitor you might have a rule that says if you're exhibiting
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Darius Lakdawalla: Obvious respiratory symptoms. We're going to send you home. We're going to make sure that people are regularly cleaning surfaces.
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Darius Lakdawalla: sanitizing bathrooms. That's all straightforward, but if you're if you're if you're going to say everybody has to work in 95 mask all day long.
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Darius Lakdawalla: That's probably not going to work out well. It's extremely uncomfortable to wear and then 95 mask it gives people headaches.
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Darius Lakdawalla: It create does actually compromise breathing, to some extent, so people already have a tough time breathing will have an even tougher time
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Darius Lakdawalla: So yes, and 95 mass if worn all the time diligently are the best way of protecting yourself in terms of wearing a mask.
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Darius Lakdawalla: But if people are going to keep taking them off. Studies show that they end up being no more effective than just a simple cloth mask that's more comfortable.
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Darius Lakdawalla: So behavior matters here, human beings ultimately have to comply with these rules and it's okay to think about that and take that into consideration.
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Darius Lakdawalla: But now, this brings us to the question of what do we do about testing and testing universally is kind of a backbone of a containment strategy that
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Darius Lakdawalla: In order to figure out how to contain the illness. We've got to know who's sick and their number of principles that needs to be deployed here.
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Darius Lakdawalla: This is a dynamic process. If you're facing an outbreak and you're seeing a rise and infection, then probably it makes sense to test more often and test more people
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Darius Lakdawalla: Similarly, you can save some money by making your test less frequent
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Darius Lakdawalla: When infection rates are on the wane, and are relatively rare. Save your money for one accounts when you're facing an actual outbreak. So that means monitoring infection rates is crucial and testing every one is crucial to because of the problem of asymptomatic spread
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Darius Lakdawalla: Now, there are three cars sets of approaches to screening people for coven the kind of traditional approach has been well let's just screen people for symptoms and test only the ones who are symptomatic. And as I mentioned,
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Darius Lakdawalla: This is a problem because there's lots of asymptomatic disease and lots of asymptomatic spread
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Darius Lakdawalla: So then the next the approach is let's test some fraction of the symptomatic and fundamentally that's probably what's affordable.
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Darius Lakdawalla: That whether you test 10% 20% 30% 50% depends on your resources, of course, you got to recognize the
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Darius Lakdawalla: It's ultimately capturing your testing 20% of the asymptomatic, then you're going to be capturing probably less than 20% of sick people among the asymptomatic, because the tests aren't perfect either
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Darius Lakdawalla: On the other hand, there's a way to make testing more affordable in a way that might also be consistent with testing large numbers of people
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Darius Lakdawalla: And this is the concept of pooled screening. So let me explain what I mean by that, and how it works. And I'll talk a little bit about the logistics of
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Darius Lakdawalla: Testing as it's being developed today.
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Darius Lakdawalla: So think about for the just hypothetically, think about 125 workers and suppose we split
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Darius Lakdawalla: This 125 worker group and the 25 pools of five workers each and that's represented here in this figure each.is a worker and each square is
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Darius Lakdawalla: A pool of five workers and the idea behind pool testing which actually dates back to World War two, when it was first proposed as a strategy for screening
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Darius Lakdawalla: draftees for syphilis, where they had screen tons and tons of young American men in a cost effective way for for the disease. The idea is
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Darius Lakdawalla: You take the specimens provided by every worker in this five person pool and you pull them together and you run a test on the pool sample.
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Darius Lakdawalla: And that test will tell you whether or not someone in the sample is sick. So you've run 25 tests on these pools of five and you figured out which pools are sick.
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Darius Lakdawalla: Right. So the first step is to test those pools. The second step is to see which of those pools tested positive. So let's say that there are five pools that tested positive here.
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Darius Lakdawalla: So what do you do well. The ones that tested negative. You say, Okay, all those workers all 20 of those pools. The covers 100 workers.
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Darius Lakdawalla: They're all clean. They don't have illness and you've achieved that that conclusion screening 100 workers by running only 20 tests. And that's the cost savings associated with pool testing.
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Darius Lakdawalla: But now we've got to figure out what to do with these five pools that tested positive, you don't know which worker in the pool is positive, but someone is
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Darius Lakdawalla: So then what you do is you run individual testing only on the five pools that tested positive and then let's say you finally find
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Darius Lakdawalla: The five individuals who were sick. The red dots here. So at the end of all of this. We've identified the five sick people out of the hundred and 25 workers that we started with.
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Darius Lakdawalla: And we've done it with just 50 tests and that is we were in the first thing we did was we ran 25 pool tests and then we ran 25 individual follow up tests 5050 tests as opposed to 125
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Richard Green: Into drives. I just want a clarifying point. So I understand the process. So you're swabbing all hundred 25 people
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Richard Green: But in terms of once you get the swab from the person you're throwing it in with those for other people, and then running a test on sort of all that stuff from those five swaps. Is that, is that correct
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Darius Lakdawalla: Right. Yeah, so logistically what happens, Richard is that you put the swaps together and the testing technology or the machine.
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Darius Lakdawalla: And the way the test works is it runs the swab through some kind of transfer medium a liquid basically that extracts
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Darius Lakdawalla: Viral material. So if you put all five swabs in to this liquid medium, then you're extracting our own material or whatever material is in the swaps from all five
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Darius Lakdawalla: And the advantages that it saves on the liquid and other agents used for the tests which are an extremely short supply globally. And so it saves a considerable amount of cost and just the physical reagents as well.
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Richard Green: Sure.
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Darius Lakdawalla: So we've saved a
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Darius Lakdawalla: Test. We've, of course, you do have to you have to collect samples from everybody as Richard noted, and there are strategies for making that process more efficient.
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Darius Lakdawalla: There are we do now have approvals for self collection. The early covert tests were extremely uncomfortable. They involve
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Darius Lakdawalla: What what's known as a nasal pharyngeal swab where the swab goes up pretty deep into your nasal cavity and it's not so fun and it has to be administered by a trained worker.
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Darius Lakdawalla: More recent advances have have provided us with approvals on nasal swaps that don't have to go as deeply in and they can be self administered
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Darius Lakdawalla: On sometimes with supervision over a video call I think typically actually that all the current approvals are with supervision, although some labs.
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Darius Lakdawalla: Are now trying to pursue unsupervised collection, particularly when it comes to saliva tests which are also in development. So that's some of the logistics around collection. The savings from pool testing comes from the testing step, you still have to collect everybody's specimens
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Darius Lakdawalla: Now, one question that you might be wondering about as well. What I just randomly said said to you, seemingly out of nowhere. Let's use 5% pools. Why, why not hundred percent pools, why not to person pools. How do we size the pools.
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Darius Lakdawalla: The choice of the pool size is really trying to balance two different issues on the one hand, if you have really large pools.
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Darius Lakdawalla: Then everything is going to come back positive, right. So think of the earlier example where we had five six people out of 125 workers.
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Darius Lakdawalla: If we had had 25 worker. Right. So in other words, five tools for that hundred and 25 worker group, we could have ended up seeing all five pools come back positive, actually, if we did if things broke
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Darius Lakdawalla: In an unlucky fashion. So if all the pools come back positive you've gained nothing from running the pool tests because you're gonna have to test everybody individually.
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Darius Lakdawalla: So you don't want to make the pools too large or you get too many positive pools. On the other hand,
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Darius Lakdawalla: If you make the pools too small, then you're leaving some savings on the table to person pools are fine and good, but they save less money.
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Darius Lakdawalla: And less resources time the agent, etc. Than five person pools, or six person pulls the optimal pool size quote unquote is the one that minimizes the number of expected tests performed per worker, and it turns out that the optimal pool size.
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Darius Lakdawalla: gets smaller, we hire infection rates and that really
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Darius Lakdawalla: That that is because of this, this point up here that when your pool sizes get bigger.
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Darius Lakdawalla: The problem is that they're more likely to test positive and that problem is more acute when your underlying infection rate as high if you're dealing with a situation where one in every five of your workers as positive
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Darius Lakdawalla: It's going to be tough for you to have big pools and if you have a 10 worker pool. You're in bad shape because you're going to have on average to positive workers in each pool. Right. So, think of it this way. If you have one in
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Darius Lakdawalla: Five workers as positive your pool size almost certainly has to be less than five workers, right, or you're not going to get any negative pools back
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Darius Lakdawalla: So what we did was we calculated the optimal pool size and understood how it varies with what you think is your infection rate.
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Darius Lakdawalla: And the lesson is that pooling actually works reasonably well for even high infection rates as long as you don't go crazy with the size of the pool.
00:27:34.650 --> 00:27:47.040
Darius Lakdawalla: That four person pools work really well, all the way up to infection rates around 12%. This is an active infection rate, by the way. So that is a extremely high.
00:27:47.460 --> 00:27:54.990
Darius Lakdawalla: active infection rate and it shows us that we still can save money and time and resources with four person pools.
00:27:55.770 --> 00:28:07.650
Darius Lakdawalla: The large commercial lab Quest Diagnostics has is expecting to get approval for four person pools within the next few weeks or hopefully by the end of the summer at the latest.
00:28:08.310 --> 00:28:12.600
Darius Lakdawalla: And that's a pretty good strategy for a wide range of cases.
00:28:13.410 --> 00:28:27.660
Darius Lakdawalla: Now you might also be wondering if I'm running a if I'm opening up a building or business, how the heck do I know what the active infection rate is. And the answer is you probably don't you probably have no idea before you begin to run your tests. How many people are sick.
00:28:29.010 --> 00:28:41.130
Darius Lakdawalla: So let's, let's talk about how to deal with that kind of uncertainty. If you knew everything you you possibly needed to know about your underlying infection rate. Here's this gold line shows you
00:28:41.640 --> 00:28:53.700
Darius Lakdawalla: How much money you can save over individualized testing and for very low rates of infection around one or 2% you're saving like 80 or 90% over individual testing.
00:28:54.240 --> 00:29:03.930
Darius Lakdawalla: This is if you have perfect information about what's going on. But the good news is you can do pretty well, just with a simple rule of thumb that says let's pull for people together.
00:29:04.590 --> 00:29:12.810
Darius Lakdawalla: You don't have to know anything about the what the underlying infection rate is. And you can see that you're still capturing the vast majority of the savings.
00:29:13.890 --> 00:29:27.990
Darius Lakdawalla: That you would get even if you knew everything about the underlying infection rate. Now granted, you're only saving about 75 76% as opposed to saving 95% over here.
00:29:28.590 --> 00:29:36.510
Darius Lakdawalla: But you're you're harvesting the vast majority of gains and you don't have to know anything over time as you learn more about
00:29:36.870 --> 00:29:47.760
Darius Lakdawalla: How prevalent infection is you can tweak the pool size and maybe gain more savings. As a result, one caveat is that it's important not to
00:29:48.450 --> 00:29:59.520
Darius Lakdawalla: Kind of take a home run swing and try to create pools that are too big because while those might this 11 person pooling approach might be really good if you have very, very few infections.
00:30:00.120 --> 00:30:08.670
Darius Lakdawalla: It becomes quite an efficient if you end up facing an outbreak. So you've got to adjust in response to changes in infection rates.
00:30:10.230 --> 00:30:24.360
Darius Lakdawalla: Now one concern with pooling is that it is more, it is less accurate than just testing an individual because for all the reasons that common sense suggested dilutes amount of viral material and a sample.
00:30:25.290 --> 00:30:32.250
Darius Lakdawalla: It creates other possibilities for contamination. When you bring swabs together. So it does create this possibility that
00:30:32.700 --> 00:30:46.170
Darius Lakdawalla: You might have a false negative meaning there's a positive sample pool sample and you actually find a negative result, maybe because you diluted down the viral material too much. And that's risky.
00:30:47.100 --> 00:30:56.070
Darius Lakdawalla: But you got to look at this in context, the false negatives are a problem that we face in all kinds of covert testing into even individual testing.
00:30:56.940 --> 00:31:06.720
Darius Lakdawalla: Most of that was due to the fact that it's actually tricky to collect swab specimens, especially the early kinds of swabs where you had to get really deep into the nasal cavity.
00:31:07.560 --> 00:31:16.260
Darius Lakdawalla: And as a result, there was some evidence that we were seeing false negatives on the order of about 30% that's really bad. Let's suggest that
00:31:16.740 --> 00:31:25.200
Darius Lakdawalla: If you have 10 infected people, you're only detecting seven of them and three of them, you're sending on their merry way to infect other people
00:31:25.860 --> 00:31:37.740
Darius Lakdawalla: Fortunately, been better since then, in terms of specimen collection errors but false negatives continue to be a problem and and pooling might slightly worse than this problem.
00:31:38.550 --> 00:31:48.360
Darius Lakdawalla: But not by much. It turns out, probably around 10% so if you think that your false negative rate is 30% pooling might make it 33
00:31:48.990 --> 00:31:59.880
Darius Lakdawalla: If you think your false negative rate is a more manageable 10% then pooling might make it 11 so it's not a huge problem and the other contextual point here is that
00:32:00.600 --> 00:32:09.840
Darius Lakdawalla: Most of the time, we're not comparing pool testing to individual testing, very few businesses have the resources to test every single worker.
00:32:10.320 --> 00:32:22.110
Darius Lakdawalla: Every other week. That's an enormous commitment of time, effort and money. So usually the alternative to pull testing of asymptomatic workers is no testing of asymptomatic workers.
00:32:22.650 --> 00:32:37.110
Darius Lakdawalla: Which needless to say, generates lots and lots of false negatives because you detect none of the sick people in the asymptomatic group. So you got to think about what the decisions are that are really in front of you. And from that perspective.
00:32:38.160 --> 00:32:47.070
Darius Lakdawalla: Routinely testing asymptomatic, even if you do it every month or even if you do it and pools is much better than doing nothing.
00:32:47.490 --> 00:33:00.510
Darius Lakdawalla: Right. And if if you might see recommendations that say test every worker every week. And you might think to yourself. That's insane. I can never afford to do that. And you might be right, but it's completely cost prohibitive.
00:33:01.410 --> 00:33:17.760
Darius Lakdawalla: But testing your workers every other week, or every month is still better than nothing from a mathematical and certainly from a common sense standpoint. So the question then becomes, how often should you test in practice.
00:33:18.810 --> 00:33:31.170
Darius Lakdawalla: MOST OF THE EARLY TESTING plans. I've seen are testing individuals every one, two or four weeks. And that's sort of the range that seems most ideal.
00:33:32.460 --> 00:33:44.820
Darius Lakdawalla: A couple of comments about this is that if you're facing an outbreak, then it makes sense to test more frequently if infection is less significant than you thought you can back off a little bit and save some money.
00:33:45.510 --> 00:33:53.490
Darius Lakdawalla: Similarly, if you're running a business where it's really hard to socially distance, you should start about testing more frequently and vice versa.
00:33:54.840 --> 00:34:11.670
Darius Lakdawalla: Another issue here is that if you have to choose between testing. Everybody less frequently versus testing only a subset of people more frequently go with frequency over size. And the reason is, suppose you decided
00:34:12.990 --> 00:34:24.870
Darius Lakdawalla: You know what, I can't test all of my employees every month. Let's say it's just too expensive, but I can test. Probably all of my employees every three months.
00:34:25.800 --> 00:34:36.390
Darius Lakdawalla: What if instead you just said, I'm going to test a random sample of one third of my employees every month. That's definitely better than testing everybody once every three months. The reason is that
00:34:36.900 --> 00:34:46.350
Darius Lakdawalla: The coven test is valuable for a very short window of time so you test your, your employees on let's say the first of September.
00:34:47.490 --> 00:35:02.280
Darius Lakdawalla: By September 15 that testing information is basically useless because there's tons more infection that could have occurred in the interim, so more frequent. In fact, and testing is very valuable because it provides you with real time monitoring of the epidemic.
00:35:03.420 --> 00:35:14.190
Darius Lakdawalla: So here are some strategies for to follow. So a baseline approach might be. Let's do pool testing. Let's test as frequently as we can afford.
00:35:15.060 --> 00:35:23.340
Darius Lakdawalla: And if if that if that proves to be a very infrequent testing regime like testing every other month or something.
00:35:23.760 --> 00:35:31.620
Darius Lakdawalla: Then it's okay to say, I'm just going to test a fraction of my workers more frequently right instead of testing every other month test half your workers every month.
00:35:32.100 --> 00:35:51.960
Darius Lakdawalla: Or even test, a quarter of your workers every other week. That's better. And then implement whatever social isolation controls are feasible with your workforce then adapt as needed. If infections are accelerating test more frequently. Try to tighten up your social isolation controls.
00:35:53.220 --> 00:35:59.130
Darius Lakdawalla: If you're seeing lots and lots of pools testing positive shrink full sizes and so on.
00:36:00.510 --> 00:36:09.960
Darius Lakdawalla: Now how do we select our pools. Well, you want one way of thinking about this is that it makes sense to pull people together when they're already exposed to each other.
00:36:10.680 --> 00:36:13.470
Darius Lakdawalla: If you have a pot of workers that are always working together.
00:36:14.250 --> 00:36:21.000
Darius Lakdawalla: And you find that pot is positive, you can immediately say, You know what, I think that infections probably spread in that pot.
00:36:21.330 --> 00:36:30.930
Darius Lakdawalla: Because the pool test tells you there's a high probability that those workers have spread the illness to each other. Some of you might have access to pool testing by family.
00:36:32.010 --> 00:36:42.600
Darius Lakdawalla: That's also a pretty sensible way of doing this because if one person is sick in the family, there's a good chance. Our people are sick, too. So the pool is heard of a natural unit.
00:36:43.620 --> 00:37:02.130
Darius Lakdawalla: In which to evaluate infection and some of you might even have the ability to do both. And that also is helpful, because you can triangulate the information. So here's the example of a school that is testing by classroom and suppose they pool their tests.
00:37:03.360 --> 00:37:09.180
Darius Lakdawalla: Across classrooms and they find that one of the classrooms is positive.
00:37:09.750 --> 00:37:16.590
Darius Lakdawalla: If you're simultaneously testing families, then you can figure out immediately exactly which kids are sick, right, because
00:37:17.010 --> 00:37:22.950
Darius Lakdawalla: If one child is in a positive classroom but isn't a negative testing family you know that kid is healthy.
00:37:23.670 --> 00:37:35.460
Darius Lakdawalla: The kids who are sick are going to be in a positive classroom and then a positive testing family. So this is another resource to take advantage of be lucky enough to have workers who can
00:37:36.630 --> 00:37:37.290
Darius Lakdawalla: Test.
00:37:38.400 --> 00:37:48.480
Darius Lakdawalla: Household or be tested as families, I'll say one last thing about this regulatory pathways, and then I'm happy to turn the questions.
00:37:49.980 --> 00:38:01.620
Darius Lakdawalla: So we are seeing pursuit of pool testing approvals already, as I said quest is pursuing in about four to six academic labs across the country are pursuing it.
00:38:02.760 --> 00:38:11.610
Darius Lakdawalla: Quest is pursuing approval for for person pools Stanford, for instance, is is pursuing approval for eight to 10 person pools and there are others in between.
00:38:12.900 --> 00:38:20.130
Darius Lakdawalla: This is going to be a bit of an arduous process and somewhat out of your control. Unless you happen to run a certified lab.
00:38:20.880 --> 00:38:28.410
Darius Lakdawalla: And the reason it's a little complicated. Is that FDA approvals are granted the very specific testing protocols. It's not as if
00:38:28.800 --> 00:38:35.130
Darius Lakdawalla: The FDA says, here's a machine that runs covert tests that machine is approved to use use it however you like.
00:38:35.970 --> 00:38:45.900
Darius Lakdawalla: Instead, it's approved for a very specific sequence of tests and might say, you can test people who are exhibiting respiratory symptoms, those people are adults.
00:38:46.440 --> 00:38:54.810
Darius Lakdawalla: And the swabs need to be collected by a healthcare worker and they need to be transported using this medium and they need to be.
00:38:55.560 --> 00:39:02.700
Darius Lakdawalla: Insert and a certain viral transfer medium has to be used to extract material, so on and so forth.
00:39:03.390 --> 00:39:11.880
Darius Lakdawalla: So as we gain approval for ours. We see approvals sought for pool tests several things will have to happen that
00:39:12.570 --> 00:39:18.870
Darius Lakdawalla: Labs will have to get approval to test asymptomatic people and also children I ideally
00:39:19.440 --> 00:39:28.110
Darius Lakdawalla: Labs will probably need to gain approval for self collection of samples as opposed to collection by a trained healthcare worker.
00:39:28.800 --> 00:39:39.030
Darius Lakdawalla: they'll, they'll need to gain approval for pooled sample testing and they'll also need to gain approval for the specific modality of test whether it's a nasal swab or a saliva test.
00:39:39.660 --> 00:39:46.470
Darius Lakdawalla: The good news is that there are labs already pursuing these approvals, we should see those materialize over the summer.
00:39:47.190 --> 00:39:55.770
Darius Lakdawalla: So pool testing should bring down the cost of testing. Today, the cost of testing ranges between 50 and $100 per test.
00:39:56.400 --> 00:40:06.300
Darius Lakdawalla: It remains to be seen. What will be charged for a pool test. My guess is that if, if, if a lab is testing a four person pool.
00:40:06.900 --> 00:40:17.850
Darius Lakdawalla: And they ordinarily charge 100 bucks for an individual test, they'll charge a little more than 100 I think for the four person pool. So let's say for the sake of argument, that
00:40:18.780 --> 00:40:29.250
Darius Lakdawalla: A lab, it would charge you 100 bucks for an individual test but 110 bucks for a for a four person pool test that effectively you're paying 2750
00:40:29.640 --> 00:40:40.890
Darius Lakdawalla: For the individual test with pooling, whereas previously, you would have paid on Dropbox. So there's your 70% roughly savings that are accruing via pool.
00:40:42.210 --> 00:40:47.880
Darius Lakdawalla: So I think I'll stop there and I'm looking forward to your questions and comments. Thank you very much for your time.
00:40:51.060 --> 00:40:54.540
Richard Green: Darius. Thank you very much for a very clear presentation.
00:40:56.370 --> 00:41:12.990
Richard Green: I just want to hit one point before we get into testing, which is you made a comment about masks and compliance and you know it's not in 95 mass, but you have whole countries that seem really good at Mass compliance with
00:41:14.190 --> 00:41:18.360
Richard Green: Billions of people when you add them up, or maybe not billions, but over a billion.
00:41:19.620 --> 00:41:24.570
Richard Green: And there. There's just a new piece out and Health Affairs yesterday that suggests that people wearing
00:41:25.830 --> 00:41:26.640
Richard Green: A model nine
00:41:27.780 --> 00:41:28.560
Richard Green: These
00:41:29.940 --> 00:41:30.360
Richard Green: Are
00:41:31.710 --> 00:41:46.950
Richard Green: substantially reduces the transmission rate of the disease on the order of, you know, they were talking about like 1.8 percentage points which for disease, which may have 2% prevalence. That's just enormous so
00:41:47.970 --> 00:41:54.570
Richard Green: You come in a little further about masks and appliance and so on. It's just Americans aren't gonna be willing to do this or
00:41:55.950 --> 00:41:56.910
Darius Lakdawalla: Yeah, and it's
00:41:57.240 --> 00:42:00.390
Richard Green: A very low cost intervention that's a pretty effective.
00:42:01.410 --> 00:42:10.110
Darius Lakdawalla: Yeah, that I completely agree. And there was a there's, there's, it was fair to say that five months ago we didn't know
00:42:11.010 --> 00:42:21.450
Darius Lakdawalla: We needed to about it. But now I think we do. And it seems clear and that master official at reducing transmission. There was a recent article also in the
00:42:21.810 --> 00:42:31.740
Darius Lakdawalla: Proceedings of the National Academies of Science, suggesting that mass for the single most important infection control measure more than social distancing lockdowns etc.
00:42:32.460 --> 00:42:51.180
Darius Lakdawalla: And it's beginning to become clear why that is. Because it's all about person to person transmission not surfaces so much are touching and in fact the door knob which other viruses can spread quite efficiently through. So that's why mass matter it is somewhat troubling that
00:42:52.500 --> 00:43:02.880
Darius Lakdawalla: We live in a country where there's no culture of mass adoption and some of these behavioral patterns are hard to shift. I think it's incumbent upon
00:43:04.050 --> 00:43:20.280
Darius Lakdawalla: All of us to figure out how we can shift those incentives and those cultural norms businesses are actually in a good position for this, you go into a restaurant that says no mask. No service. You're going to put your mask on in a hurry and not forget to bring your mask next time.
00:43:21.690 --> 00:43:35.400
Darius Lakdawalla: outdoor spaces are where you see more people on mass than indoor spaces. So whenever I collect my takeout everybody's wearing masks, because the restaurant has a stake and making sure that its workers don't get sick.
00:43:36.120 --> 00:43:49.830
Darius Lakdawalla: And I think American business should feel empowered by the evidence to take those stance that it's it's important for their workers productivity and health. It's even important for their customers. And they also care about
00:43:50.880 --> 00:44:02.160
Darius Lakdawalla: To enforce those masks requirements and it is a reasonable thing to request in most of these circumstances and 95, not so much. But the cloth map.
00:44:02.880 --> 00:44:17.430
Richard Green: Right, and I think that's where the, you know, there's this meme out there, there were a mask you going to be taking in too much carbon dioxide and they get these things. That's not a problem. The I'm 95 but actually in 95 it actually I guess really right.
00:44:19.470 --> 00:44:39.210
Darius Lakdawalla: That's right, so that that the myths about you know as fixation are just that they're myths for for a cloth surgical masks. There's no compromise. I mean, some people might find it's difficult to run a marathon wearing a cloth mask. Fair enough. But when you're interacting in a workspace.
00:44:40.380 --> 00:44:49.500
Darius Lakdawalla: There is no reason at all based on evidence to say that the mask is unhealthy cloth mask is unhealthy for the were quite the contrary.
00:44:50.310 --> 00:45:05.820
Richard Green: So we have a question from James Torres on concerns and confusion across the country regarding large assemblies could churches, synagogues service good Corbett testing locations.
00:45:06.330 --> 00:45:16.740
Richard Green: How could pastors and rabbis best setup covert testing systems that could scale across the respective denominations. So I think that relates pretty much directly to what you were just talking about.
00:45:17.850 --> 00:45:20.070
Darius Lakdawalla: Yeah, that's a, that's a great question. So
00:45:21.240 --> 00:45:30.600
Darius Lakdawalla: A couple things about churches and synagogues. So there's been you may have seen or many people might have seen the story about the church choir in Washington State.
00:45:31.410 --> 00:45:41.670
Darius Lakdawalla: That suffered an outbreak of covert in spite of practicing social distancing. And in fact, one of the issues with places of worship is that
00:45:42.840 --> 00:45:52.200
Darius Lakdawalla: A singing and also more generally shouting and SPEAKING LOUDLY and those kinds of things make are more efficient vectors of transmission
00:45:52.800 --> 00:46:01.920
Darius Lakdawalla: So you might. So there are a couple of lessons here that social distancing needs to be practiced to the max, to the extent that you're able to do it even more than six feet.
00:46:02.490 --> 00:46:11.250
Darius Lakdawalla: masks are even more critically important for houses of worship that are particularly were singing as an important part of the service.
00:46:12.060 --> 00:46:24.360
Darius Lakdawalla: And I think it's fair to say that some, some places might find these these simply impractical. Maybe the buildings too small. Maybe there's no access to remote worship.
00:46:25.110 --> 00:46:32.490
Darius Lakdawalla: And testing is kind of the alternative here that if you don't have access or the ability to implement
00:46:33.450 --> 00:46:44.430
Darius Lakdawalla: These kinds of stringent controls, then you've got to test as frequently as you can. And as often as you can. And I think, church groups are not a bad strategy for
00:46:45.420 --> 00:47:00.120
Darius Lakdawalla: fielding widespread testing in the church could be a site of testing training for testing. And there may be a way of kind of creating norms around regular testing. So I think that some ways churches have this have a similar problem, but
00:47:01.350 --> 00:47:02.910
Darius Lakdawalla: exacerbated by
00:47:04.830 --> 00:47:06.000
Darius Lakdawalla: Singing, for instance.
00:47:07.140 --> 00:47:12.540
Darius Lakdawalla: Not every church is going to have that problem. But I think there needs to be more attention paid
00:47:12.960 --> 00:47:25.650
Darius Lakdawalla: To social isolation controls and testing these kinds of and these mundane sorts of issues. How often are people close together. Are they shouting, are they shouting or is there loud talking is there singing
00:47:26.970 --> 00:47:30.990
Darius Lakdawalla: These matter and people have to pay close attention and respond accordingly.
00:47:34.770 --> 00:47:45.300
Richard Green: You know, the issue of singing. It's one of to me the greatest losses of the last three months. And as it happens, I have a number of friends to
00:47:45.990 --> 00:48:04.140
Richard Green: Either seeing in professional choirs or church and it the thing they look forward to in life. I, despite all of your helpful ideas about reopening it's hard to see how singing reopens in groups.
00:48:04.770 --> 00:48:06.870
Darius Lakdawalla: And yeah, I think that's probably right. I think that
00:48:06.990 --> 00:48:20.160
Darius Lakdawalla: We have to figure out remote strategies for those kinds of activities because we don't even really know how to establish a safe distance for a choir, for example, based on what we know today someday maybe we will. But not yet.
00:48:20.640 --> 00:48:31.200
Richard Green: Yeah, you know, and there are acquires when there are orchestras that are getting together over zoom. But that's just, I mean, it's great. And it's inspiring, but it's not as satisfying as being in the same room.
00:48:32.280 --> 00:48:42.000
Richard Green: Together. So, um, we have a question from Robin Billups my granddaughter school is working to set up pods, as you mentioned, so that they can start school
00:48:42.540 --> 00:48:54.450
Richard Green: And the additional insight would be appreciated share her school is K through high school should be entering fifth grade. So I sort of more specificity about how do you set up these pods.
00:48:55.320 --> 00:49:05.760
Darius Lakdawalla: Yeah, I think, actually, so I had an interesting discussion with the LA USD about this a couple weeks ago. And so the California Superintendent of Education.
00:49:06.780 --> 00:49:15.180
Darius Lakdawalla: has recommended or perhaps required pawns for or co hoarding is what they call it in schools. And the idea is to
00:49:16.050 --> 00:49:23.340
Darius Lakdawalla: Limit the number of students and teachers that have given student is contacting as contacted by or is contacting
00:49:23.940 --> 00:49:37.890
Darius Lakdawalla: So then you have might you might have a cohort a co worker bee cohort. A comes to school on Mondays and Wednesdays cohort becomes school on Tuesdays and Thursdays. I think that's critical, because for several reasons. One is that
00:49:39.870 --> 00:49:49.740
Darius Lakdawalla: In order to practice social distancing. Usually we have to reduce the number of students in school, very few schools have the resources, the physical building resources.
00:49:50.730 --> 00:49:59.850
Darius Lakdawalla: So space students six feet apart and existing classrooms without reducing the number of students. The other point is that co hoarding reduces the challenge.
00:50:00.390 --> 00:50:19.200
Darius Lakdawalla: Of quarantine when somebody gets sick, so if some if a student gets sick and you need to quarantine their cohort, but you can be confident that the other cohorts or hopefully not exposed to that student. So at least stumps fraction of students will not have their lives disrupted.
00:50:20.250 --> 00:50:34.800
Darius Lakdawalla: On the issue of masks. I was on in schools. I was previously in the camp that it's going to be too hard to make young kids wear masks and maybe even to our to make teenagers will do anything and watch the last were mass, but
00:50:35.910 --> 00:50:42.030
Darius Lakdawalla: I think that the emerging evidence on this suggests that we have to figure out how to make that happen that
00:50:43.230 --> 00:50:52.020
Darius Lakdawalla: It has it's yes it's going to be difficult. Yes. Teachers are going to spend an inordinate amount of their day making students, but their mass back on.
00:50:52.560 --> 00:51:02.250
Darius Lakdawalla: But it may be this one of the most effective weapons we have against the spread of coven potentially more efficacious. Even then,
00:51:02.880 --> 00:51:14.160
Darius Lakdawalla: Physical distancing, and particularly for kids who are not going to respect six feet apart as often young kids even teenagers are not going to respect six feet apart.
00:51:14.820 --> 00:51:27.480
Darius Lakdawalla: And masks Elise can be part of the solution. And finally, I'll say I think every there should be universal testing in schools whether how frequent, it is and what fraction of students are tested.
00:51:28.080 --> 00:51:35.010
Darius Lakdawalla: I'm agnostic about because those are cost considerations and you can make schools go bankrupt just paying for
00:51:35.670 --> 00:51:39.120
Darius Lakdawalla: Everybody to get tested every twice a week or something like that.
00:51:39.750 --> 00:51:48.360
Darius Lakdawalla: But we've got to monitor the progress of this illness and it'll become more important as flu season arrives and kids are showing up with all kinds of coughs colds and sniffles
00:51:48.870 --> 00:51:57.510
Darius Lakdawalla: And we're going to have to test frequently and in a widespread fashion. So those are my three things for schools that co hoarding
00:51:58.590 --> 00:52:00.060
Darius Lakdawalla: Masks and
00:52:01.200 --> 00:52:04.710
Darius Lakdawalla: Testing of asymptomatic kids routinely and regularly.
00:52:05.910 --> 00:52:16.230
Richard Green: No, I, I think you said something really important, which is that your views are have been involved in. And I think it's important for a broader audience to
00:52:17.040 --> 00:52:33.840
Richard Green: Think about how science works because you see frustrations out there along the lines of, Why can't these guys make up their minds they tell us this this day, and that the next day. And of course, it's called learning this is this is a new thing that we're confronting
00:52:35.160 --> 00:52:42.330
Richard Green: We knew nothing about it, beginning. We know a lot more now. But as we learn more. Of course recommendations are going to change.
00:52:43.830 --> 00:52:49.080
Darius Lakdawalla: That's right. And I think that you should expect some of these recommendations to change. I mean, even
00:52:49.590 --> 00:53:00.930
Darius Lakdawalla: Just as some examples. We don't have rigorous clinical trials of social distancing or even cloth mass for Kofi we're we're doing the best we can to
00:53:01.680 --> 00:53:12.960
Darius Lakdawalla: Bring information to light in real time, almost, so it will evolve so we all need to be flexible with the evidence and also to respond to changes and trends as they arise.
00:53:14.250 --> 00:53:14.940
Richard Green: So,
00:53:15.960 --> 00:53:26.340
Richard Green: I think I should notice that the paper on masks and health fair's Australia which very clever is they used as an identification strategy differences and how
00:53:26.910 --> 00:53:41.040
Richard Green: Different jurisdictions are requiring mass clearing and teasing out of that differences in the spread of disease. And yeah, that's not a controlled study. But it's again under the circumstances, I think pretty darn good. It's
00:53:41.610 --> 00:53:55.860
Richard Green: You wouldn't call it a natural experiment, but it's a quasi natural experiment or Nash natural cause I experiment or quads I natural closet anyway point. Yeah, we're doing it. People are doing the best they can and I it it does
00:53:57.750 --> 00:54:10.470
Richard Green: It worries me that people think we can have answers at any time instantaneously, and it is, I think, important for all of us to have our thinking evolve let let let me finish with one question that may be
00:54:12.840 --> 00:54:24.930
Richard Green: A little controversial, but it so long as kids don't encounter at risk people. That's a big if, is it really that big a deal if kids get this disease.
00:54:26.940 --> 00:54:33.030
Darius Lakdawalla: This is also something my thinking has evolved on if you asked me this question in March, I would have said.
00:54:34.290 --> 00:54:47.670
Darius Lakdawalla: It's not that big a deal, but the what has the evidence that has emerged, is that some group, a group of kids, which is small but not ignorable
00:54:48.120 --> 00:54:54.180
Darius Lakdawalla: Has developed an immune syndrome, similar to what's known as Kawasaki disease Kawasaki disease.
00:54:54.990 --> 00:55:05.160
Darius Lakdawalla: Where it seems to be a post inflammatory reaction to the inflammation caused by coven infection. It seems to occur, four to six weeks after infection.
00:55:05.700 --> 00:55:14.340
Darius Lakdawalla: And it results in long term organ damage for these kids damage to their heart, lungs, other critical organs in a few cases it's resulted in death.
00:55:14.940 --> 00:55:25.920
Darius Lakdawalla: Just as that to help you appreciate the numbers. I think there were so far there have been about 120 documented cases in New York State alone of these
00:55:27.720 --> 00:55:35.280
Darius Lakdawalla: Of this syndrome, which some, some people say is Kawasaki disease might be, it just because it looks like it might be different. I don't know that it has a name yet.
00:55:35.940 --> 00:55:46.440
Darius Lakdawalla: But if you if you do the math and think about, and what does that mean for the prevalence of this condition, it turns out that it would make it several times more prevalent than childhood leukemia.
00:55:48.240 --> 00:55:59.670
Darius Lakdawalla: And so if you asked me now, or if you even ask me in March. There's a new disease. It's going to be two to three times more prevalent than childhood leukemia and it's going to cause long term organ damage.
00:56:00.420 --> 00:56:07.680
Darius Lakdawalla: How do you feel about exposing your kids to that risk. I would have said, I don't feel very good about exposing my kids to that risk. It is rare.
00:56:09.900 --> 00:56:17.070
Darius Lakdawalla: So you know even childhood leukemia is rare, but it's not unheard of the kids get this disease that we that people know
00:56:18.060 --> 00:56:27.840
Darius Lakdawalla: So, that is, I think that's a reason to be careful. Now, I also, some people have taken this to say, you know what, I'm not sending my kids back until there's a vaccine school
00:56:28.590 --> 00:56:36.090
Darius Lakdawalla: And you know, I think, that is that is a debatable point, I can see why some parents would feel that way.
00:56:36.660 --> 00:56:45.840
Darius Lakdawalla: I would argue that there are significant educational costs associated with keeping so many kids away from school, but I think it's a rational
00:56:46.290 --> 00:56:54.210
Darius Lakdawalla: It's, I should say it's a defensible point of view that you want to keep your kids out of school. For this reason, I personally will send my kids back to school.
00:56:54.990 --> 00:57:07.410
Darius Lakdawalla: Provided, and I think this will happen at most schools, but there's a strategy for Co hoarding social distancing mass and testing. But to me, that would be a sufficient marker of progress.
00:57:07.800 --> 00:57:25.350
Richard Green: Okay, but it's the reason I asked the question was exactly what you're referring to is something that does worry me very much as a cost of keeping kids out of school. First of all, as you noted correctly the disparate impact, it's going to have on kids and there's no got that. That's true.
00:57:26.910 --> 00:57:31.290
Richard Green: Sometimes just some things as simple as who has internet access. Who doesn't
00:57:33.330 --> 00:57:43.950
Richard Green: But the other thing is, there was, I read a literature when my kids were in first, second, third grade on what yours are really important intellectual development.
00:57:44.490 --> 00:57:56.070
Richard Green: And it turns out, the brain is particularly pliant between about ages five and eight. And so how much you learn during those three years is really critical to your long term.
00:57:57.540 --> 00:58:07.650
Richard Green: Development and we're saying we look at long term studies now of headstart which initially didn't look to be all that effective. We now know that it was extremely effective
00:58:08.280 --> 00:58:19.890
Richard Green: On 3040 years later after kids participate in the program. So taking kids out of, you know, pretty first and second graders out of the classroom strikes me as something that is deep quite costly.
00:58:20.340 --> 00:58:28.110
Richard Green: So looking at this trade off is I think it's very uncomfortable, but very important, but the way you just characterized it
00:58:29.250 --> 00:58:31.320
Richard Green: Three times the prevalence of leukemia.
00:58:32.880 --> 00:58:34.020
Richard Green: That's pretty scary.
00:58:35.670 --> 00:58:53.040
Richard Green: So that was very helpful. Thank you. So, uh, we are coming up at the top of the hour. And so I i always like for us to finish on time Darius. Thank you very much for a very informative and clear.
00:58:53.730 --> 00:59:02.100
Richard Green: Presentation. I know I learned a number of things in the last hour and I know that our audience did as well to talk to you. So again, thank you everybody for joining us. Darius. Again, thank you very much for being here. Stay safe, everybody.