Jordan: All right, Claire. Pop quiz!
Claire: Uh oh.
Jordan: You might want to take out a pencil, but here I go. If Ontario has 426 new cases of COVID-19 in one day, and that brings the provincial total to 2,392 which represents a 22% increase, but the number of tests administered on the day tops 6,200 which is more than double the previous day’s tests in which 260 new cases were found, was today a good or bad day for fighting COVID-19 in Ontario?
Claire: Um, you know, you might be shocked to hear this, but I have no idea. But I bet there’s like 27 people on Twitter who can tell you very strongly one way or the other?
Jordan: Probably. And they’ve probably all got pieces published on Medium that include the phrase, “Well, I have a background in data analysis,” somewhere in like the opening paragraph.
Claire: Right, so you’re saying all these people that I see on Twitter analyzing numbers don’t actually know what they’re talking about?
Jordan: I’m sure that some of them do, but in the same way that not just anyone can host a daily news podcast– okay, maybe that’s a bad example– but in that, in that same way, not just anyone who knows math can analyze data about infectious diseases.
Claire: Right. Interesting. Okay, so back to your original pop quiz question. Now that we’ve had a few solid weeks of data, what are the experts saying on this? Are those numbers good or bad?
Jordan: Well, first of all, I’ll tell you, I wouldn’t be so sure about a few weeks of solid data, but we will ask an actual expert today, and we’ll do that as soon as you give us the latest numbers that we’ll throw at him, along with everything else.
Claire: Well, while we still don’t have an exact date or timeframe for when this will be over, Prime Minister Justin Trudeau says it could be weeks, it could be months.
News Clip: Everything depends on how Canadians behave. The choices you make to stay at home, to self isolate, to not go to six different stores when you go grocery shopping.
Claire: Trudeau also offered some more info about the emergency response benefit. He says those eligible will be able to apply on an online portal beginning April 6th and those who’ve already applied to Employment Insurance don’t need to apply. In Toronto Mayor John Tory said the numbers are heading in the wrong direction. He, along with the city’s medical officer of health, Dr Eileen de Villa, announced stricter measures for the city that will be in place for at least three months.
News Clip: As your medical officer of health, I am saying in the strongest possible terms, for the public to stay home as much as possible. The speed at which this virus has spread in cities around the world, including in New York City, make urgent action mandatory.
Claire: British Columbia is trying to help out residents with hydro bills. Residential customers who’ve been directly affected by COVID-19 will get a three month credit on their hydro bill. Small businesses forced to close, will not have to pay their bills from April to June, and there’s also a 50% payment deferral for larger industrial customers for the same time period. Canada now has over 9,700 cases of COVID-19 with 115 deaths.
Jordan: I’m Jordan Heath Rawlings, and this is The Big Story. Whatever the opposite of armchair epidemiologist is. Today’s guest is that. By which I mean he’s a real epidemiologist who studies the spread of infectious diseases. Dr Tim Sly has worked and taught in public health for decades. He holds a Master’s degree in epidemiology. He holds a PhD in risk studies. He is a member of the Canadian Public Health Association, the Canadian Institute of Public Health Inspectors, and the International Society for Infectious Diseases. So I’m going to go ahead and call him an expert. Hello, Dr Sly.
Dr. Tim: Good afternoon. How are you doing?
Jordan: I’m doing well, thank you. And I wanted to start by asking you, because like everyone else, I’ve been reading social media and reading blog posts and I wonder how it feels to see the entire world looking at curves and growth rates and exponentials and trying to be you, I guess?
Dr. Tim: Well, it’s delightful actually, and most of this stuff goes on behind the scenes and people don’t appreciate these finer points, but it’s now nice to talk to about people like, thresholds of transmission and incubation period and things like that. It’s quite heartening.
Jordan: What are some of the common mistakes you see people who don’t have a background in infectious diseases make when they post about the numbers that they’re seeing?
Dr. Tim: Well, we’re seeing also not just a armchair epis, but also people in the health delivery system. Most physicians are not well trained in epidemiology either. And so there’s some mistakes made in terminology and assumptions as well. But mainly it’s, I think we in general, people have too much faith in the data, in other words, the official figures, that would have been originally produced by China and is now through WHO, coming from all over the world, the data themselves are not really that reliable in this particular case. It’s a characteristic of this particular pathology actually that we have, I like to call this stealth virus because far from what you see is what you get, we know that there’s a vast proportion of virus positive people who are not exhibiting any symptoms. And so when you say, well, these are the cases, we have to really be sure that we know what we’re talking about. Are they actually tested as virus positive? Or are they clinically cases? Or are they assumed to be cases? Or that word that we’re using and people worried about it, presumptive cases? When you use them in a calculation, it’s a very, it’s a movable feast.
Jordan: Given the fact that more people probably have it than the numbers are showing, does that make you more optimistic or pessimistic about how we’re fighting this? Because again, this probably makes me an arm chair epi, but theoretically that means the death rate is much lower than we’re seeing, right?
Dr. Tim: Exactly. But you’ve got both sides of that. It’s a double edged sword, as most things in life are. On the one hand, remember that we calculate this thing called the case fatality rate. It’s not the mortality rate. That’s a totally different measure. The case fatality rate is the chance it is that you’re going to die if you’re infected. So on the on the top you have the number of deaths, and on the bottom you have the number of cases. And going back to what I was saying a couple of seconds ago, if in fact more people are virus positive than we suspect or than we’ve measured, it means that that denominator is going to be bigger so that the current situation where the denominator is smaller, where in other words, you put some figures on it, supposing we’re only measuring 70% of the actual virus positive people out there and calling them the cases, if we had the full amount there, we’d see that the case fatality rate would be much lower. And this is what we think is happening. The true case fatality is probably much closer to 1% than it is to the 3.5% or 2.5%, which is quoted by many of the official figures, including Johns Hopkins and WHO. So that’s the good side of the story, that the, the chance of dying is much less overall on average, than with the existing, you know, confirmed figures. On the other hand, it means that there’s an awful lot of people walking around with the virus in the nasal pharynx, coughing and breathing, and even talking and spreading the virus around. So that’s the bad part of the story.
Jordan: When you look at the numbers that are coming in from across the country, city by city, province by province, et cetera, how is– just bluntly, how is Canada doing in your mind?
Dr. Tim: Well, from the beginning, I think Canada comes in about halfway up the list of ideal situations. We were certainly far better than several of the European countries and the United States, who were apparently reluctant to really nail down and to have that distancing going on. I just yesterday saw the pictures from New Orleans, February the 28th at the Mardi Gras. I mean, it was just seething masses of people in the streets. And this is only, you know, a month ago, and things are really ramping up there. But we’re not as good as as the countries that really towed the line here and really began to distance themselves, such as Singapore, Taiwan, China itself, of course, which has managed to pull off almost an impossibility by, by distancing rigorously. They brought their 82,000 cases, sometimes at 3,000 a day new cases, brought it down to essentially zero. I think there were about four days where it actually was zero. And that was, that was almost like a textbook theoretical situation, but probably not achievable in reality, but they managed to achieve it. So what that’s all about is that overall, if you compare Canada with the other countries, there’s a movable thing here. We talked a few moments ago about the case fatality rate. Well, that should not really change as you go from country to country. It will change a little if, for example, Northern Italy has got a lot more older retired people in it, because they receive far more serious cases and the younger people, so that could alter a country’s case fatality rate. But in general, it’s about the same. But the figure I am talking about is the basic reproductive number. That’s the R nought, you’ve seen that quoted in different places. That’s the number of new cases you could expect given one initial case and going on down the ranks. And we think that’s about 2.6- 2.7, something in that range. It could be a little bit lower, but social distancing you see is going to reduce that. For example, if you normally in your normal day would see, I don’t know, say 20 people, you’d interact with 20 people within your two metre a little bubble normally. And now you can by sitting at home in your basement and doing all this kind of recording work remotely. You only see, say, five people. Well, that’s 25% only of what you had before. So your rate of possible onward transmission of the virus is now only 25% of what it was. What they were doing in the far East in those countries you just mentioned, because they were rigorous in their enforcement of this. They managed to bring that down to less than one, which means that the whole epidemic curve begins to go down, down, down until it reaches, in theory, and in practice with China, no more new cases. The problem with that is it, you still get a lot of susceptible people out there. I mean, they had about 82,000 cases, but on a population base that’s about 7 in 100,000. That’s all it is. So you can see that should they relax their precautions a bit, we would see a second wave begin to flood in again, and a third may wave maybe. And so that’s the problem with having done it. You’ve got, you can’t be complacent in any way at all. So Canada is about halfway up the list. We’re, we’re slower, the curve, the slope of the curve is slower here. I’m sure we will reach a big surge. But the whole idea of this, and the last month or so is to flatten off that curve, make it spread a little further on down and– but actually while we’re talking about that flattening of the curve, we’ve actually got three advantages there. One is that not everybody gets healed at the same time. I think most people understand that, so the hospitals have a better chance of keeping their head above water. The second advantage is that you may actually get a reduced number of actual cases. People are sitting in their basement they’re not talking to other people. The total number of cases is actually reduced. So mathematically, you call out the area under the curve, it’s actually smaller number of cases. So you slow it down, small number of cases. And the third advantage is that if the curve is spread flat enough and long enough, you may actually begin to encounter the first antivirals that may be coming on out of development. So we’ll actually have some therapy there.
Jordan: One of the reasons we wanted to talk to you is because we deal with the numbers every day on the show. And Claire, our producer, basically reads them out as part of her news update, and they’re so confusing and they come from everywhere and from all levels. And you know, I put a question to her at the beginning of this show and I wanted to put it to you now, just to see if there is a simple answer. So Ontario had 426 new cases of COVID-19 today, and that brings the provincial total to 2,392 and that’s a 22% increase day over day. However, the number of tests administered was more than 6,200 which is more than double the number they administered the previous day, and that day had 260 cases. So, I guess I was just asking her like how do we tell if those numbers are positive or negative?
Dr. Tim: Yeah, so this is, it’s a very unfortunate, I mean, we would like to think that those daily figures are remotely or vaguely accurate. But when you look at, when there’s a backlog, there’s a pinch point, and we’ve got a backing up of tests that should take perhaps 48 hours at most, and they’re taking up to a week, then during that period of the week, you’re seeing a lower numbers and then suddenly breakthrough another couple of analysts are coming on board and tried to clear the backlog, suddenly the cases increase. Now that’s not a real indication of the daily increase at all, it’s just how quickly we’re clearing the backlog. And unfortunately, those factors are not to be ignored. They are a very real thing. For example, during the time when China was really the centre of operations before it began to spread, we saw on one day, it was around February the 15th, I think it was an enormous surge, and that’s because they were using different criteria for testing and reporting. So, for example, if we say case, which is of course, as we said, the denominator for your case fatality rate, just the number of cases, you mentioned tested. Okay, virus positive testing. We’ve talked about the weakness of that, and that is how rapidly are we actually processing the tests? But go upstream a little bit from that one. Because of the lack of testing equipment, that’s the swabs up front, we’re seeing that the policy is changing from location to location, province to province, and also by the time as well, as to who is going to be recommended to get a test. So if you just show up and say, I’ve got the sore throat today and can I be tested? At one point they would give you a test. And now because the equipment is so much in demand and they don’t have enough swabs, they’ll say, only if you’ve got, you’re ticking off or tick off on the sheet a number of other risk factors here. You’ve just come back from overseas or you’ve got a person living in the house who’s positive, that kind of thing. So the criteria for who’s going to get the test changes, then you get the approval for the test, but the equipment’s not quite there enough. Then you’ve got the back log of the people testing it. Actually, and reporting it, and by the time it gets back to the reporting again, it’s really lost a lot of the validity and reliability in a daily report. It’s not really a daily report anymore. So when we just say the word case, which is going to be what’s on everybody’s mind, how many cases have we got, new cases? Are they in fact virus positive confirmed cases? Are the clinically determined cases, which can be sort of presumed to be a case. A presumable case would be one where you have three other people in the same nursing home with the same symptoms. They’ve been tested and confirmed and you haven’t, and we presume that you are also positive. And this was what will happen as the pandemic increases. During seasonal influenza, for example, not, not all the patients are tested. Just a very small sample. But all the others are called, they’re positive for ILI. In the case of influenza, influenza like illness. ILIs. So, you know, there was less reliance on, on a virus, positive testing and more reliance on clinical assumptions or presumptions leading to a presumptive positive. So depending on the definition of the quote case unquote, uh, it can be all over the map. And so it’s not as reliable as we would like to think.
Jordan: So I have kind of two questions to follow up on that. And the first is just because you mentioned it, it can vary from place to place and province to province, this is a comment I’ve seen some other scientists make on social media, that we need to have a Canada-wide guideline for testing and for numbers and for reporting in order for us to properly assess this. Do you think that needs to happen? Do you think that that it varies enough province by province? What’s your, what are your thoughts on that?
Dr. Tim: I think what’s happened is that we sometimes see people being asked do you think that Canada was prepared for this? That’s one of those profound questions, and the answer has to be no. Nobody in the world was prepared for this magnitude. Remember that the last time we had something like this was 102 years ago. And nobody has that living memory now of what that was like. We’re having to go back to reports and ancient to yellowed textbooks and the notes made at the time. So we’ve lost touch completely with several generations having gone by. Nobody was prepared for this magnitude. Even the 2009 H1N1 influenza, that took everybody a bit by surprise. That was a true pandemic. Remember, pandemic has got nothing to do with how serious it is. The 2009 influenza was actually relatively mild. It was about as mild as seasonal flu actually. But even that one took people by surprise simply because there’s so many people getting ill at one time. I’m sure that after this dust is settled and the smoke has cleared, the public health agency of Canada, which was only put together as a result of SARS, which is only less than two decades ago, they will revamp up and demand lots of extra resources and provisions for the next pandemic because there will be one. There’s always one, there’s two or three every century. And we’re maybe even in a better situation with, for example, lots of testing kits that are hanging around, waiting to be used. But of course, we don’t know what the disease will be. In this particular case, the testing kits needed that nasal pharynx swab, which is, it has been used for influenza as well, but who knows what the next disease will be. But yeah, we will be more prepared for the next one. But I think what’s happening here is that it just simply the volume of the number of people, and this is what’s happening, and modern hospital works very well, but think of it now, if you know anybody who works in a hospital, they’ll tell you that on a normal, cheerful day, operating as usual, if two or three nurses on the ward are off ill for some reason, it’s a bit of a scramble to fill in those shifts. That’s two or three nurses out of perhaps a thousand in the hospital. Now you imagine what’s happening now as the surge begins to build up, you have perhaps, let’s say 30% of medical staff, of all types, doctors, nurses, attendance, lab techs are off ill. 30% that’s 300 out of the thousands of people. In addition, you might have another hundred off, 10% because they’ve got somebody in their family who’s positive and they have to quarantine themselves as well. You may get another 10% off because, well, we know that 32% to 38% of nurses have children in the school. So when the schools are closed, somebody has to stay home looking after the kids. So now you may be down, you may be down to about half of the frontline medical nursing staff in a hospital. Cause they couldn’t handle half a dozen off, and now they’re down to half what they were. At the same time, you’ve got 700 people at the front door banging on the door, waiting to be let in because they’ve got grandpa in tow and he’s starting to turn a bit blue because the pneumonia is starting. Can you see the impossibility of this? Nobody could prepare for this. And that’s what we’re heading for.
Jordan: Well, given that then, because it seems like that kind of scale is not that far away, and all we’re doing is we watch the reporting is hoping that we can flatten that curve before we get there. What numbers, considering I get lost in them, what number do you watch? Given all the uncertainty out there, when all those reports come out from Ontario Public Health, BC public health, from the Canadian government federally. What are you looking at?
Dr. Tim: There are people out there who are thinking well this, it may well infect every single person. And that’s not the case. We have a natural set of breaks that go on, even if there’s no antivirals, and it’s called the threshold of transmission. And it comes from the fact that people who develop the the infection, let’s say 1% of people die on average, well the 99% of people who survive are going to now have a set of antibodies in their system. We don’t quite know how long the antibodies last. They, on the one hand, they may be permanent such as with polio. It may be it lasts only a year or so, as with rabies or whatever. But we don’t know. So let’s assume though, for the short term, everybody is replete with a set of antibodies, which means that the more of these people who are recovering and entering society, again, these people are made of asbestos. They’re fireproof. This thing is not going to affect them at all. And as that proportion begin to increase, we’re approaching what we, what– you’ve probably heard this term, the herd immunity. So that the proportion of people who are now immune, because they’ve gone through it, increases. The people who are susceptible, who haven’t got it yet, begin to decrease. And those two curves begin to meet. It very much depends on the calculation behind the scenes, but for this particular disease, if nobody was in lockdown. Or not very many people, and we, we assume that R factor was about 2.6, we would reach that in about 60% of the population. So with an idea of the population of Ontario, and we’re looking at that, we know that if we did nothing, we would have about a 60% maximum before the curve began to go down. But because we’re taking some precautions and flattening it off a bit, we’re going to see that much less. If we can get that down to one, for example, sorry, two exactly for example, we’d be down to 50%, is all we needed naturally before the cases began to go down again. If we could get it down to even less than that, it could be 40%. So we’re looking to see these numbers on a daily basis, poor as they are, the doubling rate. These are the exponentials stories. You know, you can always fool people at parties and online about the poor nature of the human brain in grasping exponentials. In our case, we want to see how long it takes to double. And so in Italy, for example, it was doubling at about every three days. That was one of the worst examples. That’s beginning to flatten off a little bit now. Ontario really hasn’t reached its peak, so we don’t know how, how successful this distancing is. We don’t know how, how short a period it’ll take before we see this period of doubling. I think it’s about four to five days at the moment. Let’s hope it doesn’t increase. If we keep it like that, or even extended a bit longer again, that bulge, that the peak of the curve will be pushed further on down. Now there’s a negative part of this, as everything in life, if we push this curve nice and flat push it ahead, it means of course, that the catastrophic social and economical impact is going to be extended as well. There’s a philosophical way of looking at this, and it’s been proposed by our colleagues at UofT, that we might see something analogous to putting on the brakes going down a Hill and then releasing the brakes off again, the car begins to accelerate and putting on the brakes, in other words, clamping down with a distancing and then taking the feet off a little bit when the numbers are going down, letting it build up again and putting it back on again. Whether that would be a realistic solution, I don’t know. It might sort of extend it halfway if you’d like, the people at home not doing their job, you maybe only get half of them like that, but they haven’t to keep putting the head back there in the basement again, every so often. I’m not sure that’s really a solution, but it’s one possibility that’s been proposed.
Jordan: Well, thank you so much for helping walk us through what is a very confusing set of numbers for us to look at daily. And I’m going to take some of those tips and apply them.
Dr. Tim: Thank you very much indeed. I’m pleased to help at anytime.
Jordan: Dr Tim Sly. Like I said at the beginning, a very qualified expert on infectious diseases. That was The Big Story. If you would like more big stories, we’re all COVID all the time until this ends. Hopefully soon. You can find them at thebigstorypodcast.ca you can find us and any podcast player you prefer. Always rate and review, and of course you find us on Twitter at @thebigstoryfpn. And we would like to find your clips in our inbox. If you want to tell us what your new normal looks like, just record with the voice recorder on your phone or take a video and send it to firstname.lastname@example.org. I will leave you now with a listener named Dawn who’s spending some quality time with the little one. Thanks for listening. I’m Jordan Heath Rawlings. We’ll talk tomorrow.
Dawn: Hi Jordan. Thank you for doing your wonderful podcast. I listen to it all the time. It was very informative on the relief coming for COVID-19 what I’ve been doing with my time, I’m on the tail end of a mat leave. My little one’s just about to turn one, so I’ve been in an employment bubble, being on my job, protected leave. Here’s my challenge in regards to who qualifies and who doesn’t. Just before I was pushing to get daycares and confirm a spot so that I can return to work in April, all the daycare’s closed down and then I received notice from my employer that they would not be bringing me back, with essentially no severance. So I’m technically still on mat leave, getting employment insurance for another month or so, but not quite sure what I’m going to do after that. Pretty confident in my skills that I could find a job if we weren’t all self quarantining and if I had some knowledge of when I could get care for my child. So I’m a single mother, so daycare will be necessary for me to go back to work. It’s been interesting. I think I can float myself for a couple of months, but just, I’m in a very unique situation. So the self quarantining has been learning to walk for an almost one year old. He’s doing well. But just trying to figure out what’s going to happen after April. But once again, thanks for your podcast. It’s been really interesting and informative. Thank you.
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