Ep. 53: The COVID-19 Rapid Antigen Test Explainer
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Rapid antigen tests are cheap, easy and deliver results in just minutes—and their mass distribution is being touted by experts as something that will be crucial to helping society return to normalcy. In this episode we interview two of their pioneers. With her pilot program in Halifax bars and restaurants, infectious disease specialist Dr. Lisa Barrett was among the first in Canada to deploy pop-up testing on a mass scale. And author Joshua Gans spearheaded the thinking behind Canada’s largest rapid testing pilot, led by the Creative Destruction Lab, where Joshua is the chief economist. By exploring the perspectives of these pioneers, guest host Dr. Peter Nord investigates an important new COVID-19 containment tool.
Links, references and highlights:
A Globe and Mail story on Dr. Lisa Barrett’s rapid testing trial in Halifax bars and restaurants
The Creative Destruction Lab’s Rapid Screening Consortium
One of the most popular rapid antigen tests is the Abbott Panbio. Learn more about it.
A New York Times story on Canadian rapid-testing efforts is here.
Plugging the Gap is Joshua Gans’ newsletter covers the pandemic as an information problem that needs information solutions.
Joshua Gans’ just-released book is The Pandemic Information Solution: Overcoming the Brutal Economics of Covid-19.
Follow @joshgans on Twitter.
Follow Dr. Lisa Barrett on Twitter @LisaBarrettID
The Rapid-Testing Explainer final web transcript
Christopher Shulgan: Welcome to episode 53 of Eat Move Think. I'm producer Christopher Shulgan, and this episode features interviews with two people who are pioneers in a form of COVID-19 screening that is faster, cheaper and easier than what public health authorities currently are using. So much so that many of us may be doing it soon several times a week. They're called rapid antigen tests.
Christopher Shulgan: They're similar to home pregnancy kits, in that they deliver the result only minutes after they're conducted. Antigen tests aren't as accurate as the gold-standard PCR form, but they don't have to be. Instead, deployed at a mass scale by employers across the country, they're said to be just good enough to form an added layer of protection, to stop outbreaks.
Christopher Shulgan: In fact, Medcan and the Medical Advisory Services Team that provides guidance to Canadian organizations, is participating in the nation's largest rapid antigen test pilot through the provision of nursing services. That pilot is led by the Creative Destruction Lab's Rapid Screening Consortium. Today, we're featuring Medcan Chief Medical Officer Dr. Peter Nord's conversation with Joshua Gans, the CDL's chief economist, whose thinking laid the foundation for the rapid screening pilot, and who just released a book, The Pandemic Information Solution: Overcoming the Brutal Economics of COVID-19.
Christopher Shulgan: But before we get to Peter's conversation with Joshua, we feature the perspective of Dr. Lisa Barrett, who spearheaded one of the nation's earliest rapid-testing pilot programs to screen patrons at Halifax bars and restaurants, and which, to date, has tested more than 18,000 people. Here's Dr. Lisa Barrett.
Lisa Barrett: My name is Lisa Barrett. I'm an infectious disease doctor at Dalhousie University, and I'm also a viral immunologist at the Faculty of Medicine there as well. I am an expert in chronic viral infections, and the immune system changes that get you there in terms of protection.
Lisa Barrett: So I'm based in Halifax, Nova Scotia, and rapid testing became a part of our environment in about November. We had a very, very firm grip on the first wave of the pandemic. We had reopened our restaurants and bars and gyms for about several weeks at that point around the beginning of November, end of October, to almost full capacity. And that hadn't changed our case number, and we were still only doing testing in people who had symptoms. However, that didn't seem to make much sense. We really didn't know how much virus was in the community until we tested people without symptoms.
Lisa Barrett: And we finally went back to public health, myself and my colleague, Dr. Todd Hatchette, and said, "This is a no go, we're gonna go do rapid testing down where it's needed, where people are without masks around each other. Period." And that's how we got started one night at a closed down bar in downtown Halifax to get rapid pop-up testing started for people who were in a social situation.
Lisa Barrett: This was not an easy concept. The concept of pop up testing where you were going to do rapid tests. They weren't perfect. They were going to miss cases, we were going to end up in situations where maybe not everyone would get reported to public health. This is a reportable disease. What would happen if we missed someone who was diagnosed and it didn't get reported properly? What about people who looked at this as a way to throw caution to the wind once they were tested, and go forth in the world as if COVID didn't exist? So that was the drama of the day. And finally, we got this approval, which took a bit of convincing of a lot of people. Because not only were we going into a bar, which sometimes public health is not keen on health interventions happening in an establishment that serves alcohol, but also, we were going to do this by training non-medical professionals to do the test and the swab. So this was causing the next layer up of drama.
Lisa Barrett: And we took a few volunteers from the community, mostly word of mouth from our immediate colleagues' family and friends, to be honest. Got a business partner in the community who said, "Sure, bring it on." And we got approval from the Premier's office eleven o'clock the night before. And at two o'clock on a Saturday afternoon, we were down cleaning dusty tables in a shut down bar, and set up basically a testing site within 45 to 50 minutes. And suddenly, we were testing 160 people-ish that night: staff and patrons who were going to either work or out for the night. And we did find actually a real positive. That was someone who lived in a high number household who was found very early and then did not transmit on to the rest of his family and friends. So that was our first night.
Lisa Barrett: We weren't thinking of this test, just as a diagnostic test. That's a medical thing. This is a tool of engagement to let people start to own their own ability to know their status around COVID. So that's a tool of engagement, not a diagnostic test. So we went from 150 one night, then we just had word of mouth volunteers go out, some logistics people who helped us get things going. We went to a downtown site that actually happened to be Dalhousie's engineering building that wasn't in use for in-class purposes. And then three days later, we were doing 1,142 people every six hours. And so we ramped up in three days the whole model, not using lab resources to 1,142 people in the public a day at our maximum.
Lisa Barrett: So it was rapidly scalable. You walk in, super low-tech. Not gonna lie. You give someone your full name, no health card necessary. You give them your cellphone number, they text us their cellphone to an encrypted phone. They go through, they get their swab, they get some counselling, you're neg for the night only. This doesn't mean you got to do anything else different. If you're positive, we're going to get you back to do a positive confirmation test. And, you know, go forth, safer social. They leave. They're usually in and out with registration in about three to four minutes. And usually within 30 minutes, people got the text with their result. 72 hours later, after everything has been confirmed that you got your test, etc., your name is erased from that system. And all we have left is just phone numbers, because that's what we use for reporting to the federal government for test usage.
Lisa Barrett: So for our rapid pop-up testing in Nova Scotia, we exclusively at the moment use the Abbott Panbio rapid antigen test. That is different from the PCR test that we do, in that the PCR test detects genetic material from the virus. It is very, very, very sensitive, it is very specific. But also, it takes a lot of lab resources to do. The Abbott Panbio is an antigen test. And that means that it actually detects bits and pieces of the virus, not just the genetic material, but the actual parts of the virus that make up its physical structure. And so because of that, you have to have enough virus present in order to be able to detect it. And so that means in certain situations, like very early in infection, it may be slightly less sensitive, or less likely to pick up the virus than the gold standard.
Lisa Barrett: The way the test works, the Panbio, is that you take the deep swab, the nasal pharyngeal swab, you collect it, and you put it into a little tube that's about three inches high that has about a two-centimetre level of fluid in the bottom. That fluid kind of leaches out all the bits of the virus from the swab that was in the nose. You swirl it around four to five times, and then you take the bottom of the tube off, and you put five little drops of that fluid that came from the nose onto a cartridge that looks a little bit like a home pregnancy test. And then the five drops just by the way they leach forward, the fluid carries on up the length of the stick, and it has a color change. And if you get one line, that means your control is positive and this test worked, but you are not positive. If you get two lines—just like a pregnancy test—the test worked and you actually have evidence of COVID-19. So what we do in those cases is then bring people back for an immediate re-swab to make sure if they do or do not actually have COVID-19. We've done about 18,000 in various different venues around the province. There were, I think, 42—it's close to that number—that were positives, and a good chunk of those were false positives.
Lisa Barrett: For me, having a rapid or pop-up testing environment that makes things easy for people means something very special for the rest of Canada. We use the term "Neg for the night," so if everyone in a certain environment, in a restaurant or whatever, got tested, this is the safest place you can be for the next 12 hours without a mask. Not that that would go against public health rules. you still follow all the rules, but the ability to know that everyone in a certain space is negative is an incredibly powerful way to get people back to doing the things they need to do. Not guessing they're safe, but knowing they're safe.
Lisa Barrett: Eventually we want the tester and the testee to become one. And until then, until we get there, having people take ownership of their own testing is the way we're going to keep things open, even with vaccines because this virus is going to change, and testing is going to be a bit of a part of our lives for quite a while. And I think if we can get that out, that's important.
Christopher Shulgan: That was Dr. Lisa Barrett, the infectious disease specialist at Dalhousie who spearheaded one of Canada's first rapid-testing screening programs in Halifax. Now, here's Medcan chief medical officer Dr. Peter Nord in conversation with the Creative Destruction Lab's chief economist, Joshua Gans, whose thinking formed the foundation for the nation's largest rapid screening pilot.
Peter Nord: Hi, I'm Dr. Peter Nord. I'm the Chief Medical Officer at Medcan. We're excited today to be speaking with Joshua Gans. Joshua, you're the chief economist at the Creative Destruction Lab, and the author of the book, The Pandemic Information Solution. First of all, thanks for being on the show. Your book portrays the pandemic chiefly as an information problem, which I found really interesting. Can you tell us a little bit what that really means?
Joshua Gans: Yes. So basically, since the start of this pandemic, people have been talking about it as if it is a health problem, which of course it is. It's a health calamity in many respects. But there is this other way of looking at it, and it's a particular use for the things that I'm interested in, which are the economic consequences of us dealing with the pandemic. And that is the problem that we just do not know at any given time who is infectious, and therefore, who should be isolated. Instead, what we do is, since we don't have that knowledge, we're forced to treat everybody as potentially infectious.
Joshua Gans: And we engage in social distancing, mask practices, PPE, and a whole lot of other things that we've experienced over almost a year now. And those have grave economic consequences as well. And there's a tragedy to that, because at any given time, amongst thousands of people, there might be only one infectious person. And so we're taking many thousands of people and treating them the same as the one infectious person, which does nobody any good, including the infectious person themselves. And so the way in which I found it useful to frame this was, well, what are the things we can do to more properly identify those who are the riskiest people in the population, and target our interventions for that, and therefore allow us to proceed more normally in terms of our ordinary lives?
Peter Nord: Yeah. So a stratified approach, really. I think in the book you say we want high-quality COVID-19 tests that, as a matter of standard, give us information that is similar to the information that we get from visible symptoms of different viral infections. To your mind, how do we get there?
Joshua Gans: Well, there are several ways in which we can sort of improve our prediction of who happens to be infectious or not. You know, in previous pandemics, the virus has actually helped us themselves by having symptoms present at or even before someone becoming infectious. So that's a great tell, and that allows you to deal with things. And actually, with SARS and MERS, that turned out to be more than enough. And compared to COVID-19, those pandemics, despite being potentially more infectious and certainly having graver health consequences, were rather short lived and relatively contained. Obviously, with COVID-19, we found out pretty early on that there could be asymptomatic and certainly pre-symptomatic carriers.
Joshua Gans: And so that presented this huge problem. So how do you resolve that? Well, you know, many countries in the world were already ahead of that problem even if they weren't putting it as I have as an information problem. Countries like South Korea, for instance, had had previous experiences with, in particular, most recently MERS. And it set themselves up being able to have mass testing of the population at an early stage, and also a contact tracing regime that we could debate the privacy issues associated with it, but it's a very, very effective way of being able to track outbreaks both forward and backward. And so these are the sorts of things that can be very valuable at the outset of a pandemic to keep it in check.
Joshua Gans: But also, there's no reason why they can't also be used in the midst of it, as we have here in Canada, rather than what appears to be now a cycle of lockdown, reopening, lockdown, reopening, that could go on for another year. Wouldn't it be better to take advantage of times when our prevalence is relatively low to start investing in systems to identify infectious people quickly?
Joshua Gans: The one thing I've noticed is that there's been way too much optimism over the current intervention, or things like vaccines and things like that to get us out of this mess. We're going to face real supply constraints for vaccines, and we're going to have to think very carefully how to distribute these things, not only to protect people, but also to suppress the outbreak. And it's kind of hard to do everything. So we're in a bit of a mess at the moment, because a vaccine has never really got us out of a pandemic ever. The closest thing was polio, but that was a long time coming. There are variants that crop up that the current vaccines may or may not be able to handle, and so this thing could become endemic and could circulate around in different forms.
Joshua Gans: Certainly, the last time we had a global pandemic, 1918, gave us that. So your bets would be on that sort of thing. And so what I would like to see is a system by which we can screen people, have everybody feel much safer. And I think we're working towards that, and hopefully, we'll get there.
Peter Nord: Yeah, and certainly the vaccines are never 100 percent. Not only are they not 100 percent effective, but we don't have 100 percent of the population that are going to be taking the vaccine. And yet, you know, the rapid turnaround test that we're looking forward to, they're not 100 percent in terms of sensitivity or specificity. And so it we've mentioned this before, that they're really—the rapid turnaround test, cheap, effective, can be done anywhere, are a bit of a game changer, especially when you overlay the vaccines on top of that, but independently, not as effective as maybe headlines would make out to be.
Peter Nord: But put them together, the rapid turnaround tests with a vaccine program, will get us there or get us there a little quicker. In the book, you talk about the rapid antigen test being a much better than a temperature check. And obviously, cheaper, faster, quicker, easy to distribute. But maybe you can just go into that for a second.
Joshua Gans: No, absolutely. So the starting point for thinking about any of this is: why do we test? So PCR tests are this modern miracle, they can test the smallest amount of the virus in you. They can test it in wastewater sewage, for goodness sake. You know, that's why we call them very highly sensitive, because they can pick up little traces. But there's a difference between being infected with the coronavirus and being infectious.
Joshua Gans: Over the course of when you'd be able to detect the virus in you, there's only about a third of that time that you're actually infectious, that you'll have enough of a viral load that you're shedding the virus and you can cause harm to others. And in particular, the back half of that cycle of the virus in you, the virus has become inactive. And so the PCR test which can pick up the genetic remnants of the virus doesn't care whether it's active or not, dead or alive, essentially. But obviously, we do. It's not a danger, an inactive virus in you. It's not an issue for anything.
Joshua Gans: So what you're really interested in, is not knowing if someone's infected or not, you're interested in knowing whether they're infectious or not. And it turns out—and this is probably purely by luck rather than design, but it's robust—the antigen tests, while not being as sensitive as the PCR test for detecting the virus in you, are going to lead a positive outcome when the virus is high enough that you'd be shedding it.
Joshua Gans: In other words, the point at which the antigen test tells you that you're positive overlaps with the portion that you're infectious. So it doesn't matter if it's missing the ends, so to speak. And one of the problems we're facing is that the antigen tests have all been benchmarked against the PCR tests. But this is like taking a smoke detector and saying, "I want the smoke detectors that can pick up the littlest whiff of smoke," and installing it in your house. Well, you know what the problem's going to be there, it's going to go off the minute you light the stove.
Joshua Gans: So we don't do that. We don't. We say, "I want a smoke detector that's gonna come on when there's enough smoke that I'm worried that there's fire. Same sort of thing should be with testing for the purpose of whether someone's infectious. Not if you want to treat them and other things like that, that's very different. But if I want to know if someone's infectious and say, "All right, you're not coming in here today, and probably for a while," this is what I should use. And moreover, it has these two other advantages. The first advantage is it's really cheap. That means we can scale it. The second advantage is it gives a very quick result. So we don't have to wait 24 hours to know if someone's infectious or not, and have them walk around doing God knows what during that time.
Joshua Gans: Oh, and the final thing is, of course, because it's cheap, we can do it frequently. You don't have to just give one test and everybody goes home and doesn't think about it again, you can put it in a regular cycle. So even if you for some reason miss something, someone, you'll catch them two days later, and you'll catch the people that they catch. And so you can break these chains of transmission. And so it's not going to be a wall or a secure bubble or something like that, but it's gonna get the problem solved, which is these transmission chains seeping throughout the population, exponentially growing and causing harm.
Peter Nord: People are motivated because this is a key step forward to getting their life back and small price to pay. And we've seen south of the border in the US, there's been a pretty broad deployment of rapid tests. Bit of a shotgun approach, not a ton of oversight, not a lot of rigour around the science. It's been, you know, a shotgun approach. In Canada, we really haven't seen these tests distributed at all. I mean, we're just starting to see some of them in long-term care settings. They're doing the pilot studies now, that's obviously in the public health side system. Why do you think we've been delayed in Canada in terms of the deployment?
Joshua Gans: Look, I think it's just knowing how to what to do with them. As you said, there's been some of this going on in the US, but it has been a shotgun approach. And the tests are a little bit different. And I think it's really just a matter of knowing what the procedures are. And what we've found is even in our corporate environments with all manner of resources and certainly motivation, there are a lot of issues to work out. There are a lot of things to think about. There are challenging issues about how frequently do you test people? And how do you deal with weekends? Because I want to test people twice a week, but eventually one of those dates comes on a weekend. And what if they're part time workers, or what—like, it goes on and on and on. So we're working all that out to get to something simpler. So that's our thesis of why these things haven't been pushed.
Peter Nord: Certainly we've heard about saliva testing, and even like a breathalyzer. Blow in here, and we'll tell you if you're green or red relative to COVID. Are those things on the near term, or is that over the horizon?
Joshua Gans: Yeah, we've seen a lot of those. I've seen some purport to have something like a metal detector that you can walk through, and they can determine if you've got COVID. Others—and I think it's already in the field, some places where they're testing your smell, whether you can smell or not. For that, I don't know, you know, whether that's gonna do it or not. The hope is that, at some point, we will innovate enough to find very efficient ways of doing this. But this is all a delicate balancing act, there are risks everywhere you look, there's risks when doing stuff, there's risk when not doing stuff. And there's different people with different preferences for different sorts of risks. So getting this all together into a system is quite difficult.
Peter Nord: Yeah, like changing the oil in your car going down the highway. There's a lot of moving parts right now.
Joshua Gans: That's essentially what we've been doing. I mean, all the pandemic preparation was contingent on keeping the outbreaks out. Let's be very clear. I mean, you know, people compare the coronavirus and the flu and other things like the flu. And the flu is bad, not as bad, but it's bad enough. How is it that we have let that keep going on for now a century as an endemic thing? We have a vaccination program. Is there more that can be done because, you know, it could be a flu-like thing the next time? It could be something like that? I feel we don't understand it. But the idea that we've got any infectious disease circulating that is harmful to both people in terms of productivity but also in terms of fatalities, this is crazy. Why would we want to live with that? Because it also appears to be that the rate of return on almost anything to do with infectious disease prevention is sky high. Is sky high. They're the most no-brainer activities that you could find in economic life is doing something about anything that is an infectious disease.
Peter Nord: Also in this episode of the podcast, we're featuring an interview with Dr. Lisa Barrett, who's been running a program in Halifax since November that's using the Abbott Panbio testing kits to screen patrons of bars and restaurants. Have you heard of her effort, and what do you think?
Joshua Gans: Yes, absolutely. Nova Scotia was early for the rapid antigen testing. And I believe that was mostly her doing, and to her credit, to be rolling out these pop-up sites and other things like that, to allow sort of broad testing. That's obviously a great option, the idea that you can take an entire bar and test its patrons is surely going to be a good thing to have happen. I see that as complementary to the work that the CDL Rapid Screening Consortium is doing. That consortium is really looking for situations where people are going to be regularly screened. And so that means that you're coming into a place every day, and twice a week you're getting a screen. And why that's important is that if we have enough people in a workplace doing that regular screening, we can break those chains of transmission.
Joshua Gans: So I'm going to watch with great interest to see how that continues going. I would like to see similar things happen in other provinces, because in Nova Scotia, you know, obviously, they've handled the pandemic very well, there just aren't going to be that many asymptomatic cases. It'd be interesting to see how this occurs in Ontario as we open up places and things like that. But basically, there could be anyone who's of interest to be rolling these out in workplaces. And the CDL Rapid Training Consortium, we're kind of full up on people we can run pilots for ourselves just to manage and learn from. But very soon, and in a matter of a month or two, we will have a standard operating procedure manual that anyone will be able to download from our site, and hopefully get cracking on implementing this stuff.
Peter Nord: Joshua, thank you so much for the time today. Thank you for the work you're doing. And thank you for the book, I really enjoyed reading it. And we'll have to have you come back and give us an update maybe in a few months as we see how things roll out. So once again, on behalf of all the listeners, thank you so much for your time.
Joshua Gans: Thank you. Yes. I'd definitely like to give an update, and I hope we have lots to update you about.
Christopher Shulgan: That was the Creative Destruction Lab chief economist Joshua Gans in conversation with Medcan chief medical officer Dr. Peter Nord. That's it for this episode of Eat Move Think. I'm executive producer Christopher Shulgan.
Christopher Shulgan: We post highlights and the episode transcript at eatmovethinkpodcast.com.
Christopher Shulgan: Eat Move Think is produced by Ghost Bureau. Senior producer is Russell Gragg. Editorial and social media support from Emily Mannella, Tiffany Lewis and Chantel Guertin.
Christopher Shulgan: Remember to rate and subscribe to Eat Move Think on your favourite podcast platform. Follow our host Shaun Francis on Twitter and Instagram @shauncfrancis—that's Shaun with a U—and Medcan @medcanlivewell. We'll be back soon with a new episode examining the latest in health and wellness.
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