COVID-19: The week in review with epidemiologist David Fisman (April 19-24) speaks with the University of Toronto professor about the testing, the numbers, and the outlook for Ontario
By Nathaniel Basen - Published on Apr 24, 2020
The Ontario government released new COVID-19 modelling earlier this week. (



David Fisman, a professor of epidemiology at the University of Toronto’s Dalla Lana School of Public Health, has been one of the most prominent critics of Ontario’s response to COVID-19. He’s also involved with the province’s coronavirus-modelling group, which provided updated projections earlier this week. is checking in with Fisman on an ongoing basis to get his insights into the week that was — and the week ahead — in the province’s fight against the coronavirus. We caught up with him on Thursday afternoon. This has been an important week in Ontario’s epidemic: Governments are talking about the circumstances necessary to reopen the economy. New modelling has come out. What strikes you about the overall numbers of deaths, hospitalizations, and cases?

Fisman: I think this is somewhat of a continuation of what we discussed last week — that is, the epidemic in Ontario seems to have split off into a community epidemic that’s subsiding and an institutional epidemic that’s taking off. Increasingly, we see that the deaths in Ontario are now happening in long-term-care settings and in vulnerable communities. The province, at long last, has started getting serious about locking down workers to single long-term-care facilities, ensuring there’s personal protective equipment. There’s a testing blitz going on in long-term-care in Ontario. 

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That’s all great, but it’s a little bit like closing the barn door after the horses have escaped, unfortunately. I think, given the province’s numbers, there are about 2,000 people affected in long-term-care facilities, and, given how frail that population is, I think we’re going to expect to see deaths continue to rise in the weeks to come. We have a number of hospital outbreaks now throughout Ontario, which is a problem, and we have hospital outbreaks now in Quebec, as well. So, while the epidemic does seem to be subsiding in Canada as a whole, Ontario and Quebec do seem to be a little stuck on the way down with these institutional outbreaks. Alberta has also had some setbacks this week, with a large outbreak associated with a food-processing plant, and I believe one of those has now occurred in British Columbia

To the point about wanting to reopen the economy: this disease is showing us that it’s not going away quietly, and it’s found places that it can continue to cause death and destruction — and it’s hanging on in those places. We basically have to be patient and keep doing what we’re doing — do better at some things, particularly in the hospitals and institutions like long-term care and prisons — and stick with it. We will get there, but one almost sees in the public dialogue this tremendous desire to declare victory and reopen the economy. I don’t think things are going to work out for us that simply. 

The other really interesting thread this week has been our improving understanding of just how much disease we are missing. New York State came out with a seropositivity study today that suggests that 10 or 15 per cent of their population has been infected in their large epidemic that’s unrolled over the past six weeks. We’ve seen similar numbers over the past two weeks from places in Germany, the Netherlands, Switzerland — there’s a study in Brazil that I’m aware of, and, famously, a couple of studies from California. These studies all have variable attack rates, but they all suggest that, even in rich countries with a lot of resources devoted to testing, we continue to miss the overwhelming majority of these infections. So we’re missing anywhere between, say, 85 per cent and possibly up to 99 per cent of these infections, depending on which numbers you use. 

In terms of the plan to reopen the economy, it makes me quite pessimistic that things like contact tracing and isolation of cases in quarantine and quarantining contacts will really do much to keep the disease at bay in the community. You mentioned re-opening the economy. Premier Doug Ford has said that Ontario’s will reopen slowly. Saskatchewan has presented a plan. We’re starting to hear the concept of “herd immunity” discussed more by government leaders and others. What goes through your mind when you hear that? 

Fisman: The word “yikes” goes through my mind. The word “cruelty” pops up in my mind. The word “irresponsibility” pops up in my mind. The word “greed” pops up in my mind. I think there’s tremendous pressure at this point — Premier Ford is exactly right; he’s taking it incrementally. That’s the way you have to do it. 

We’ve seen New York basically totter on the edge of collapse. New York City has gone through over 1,000 deaths a day. These are people’s brothers, sisters, mothers, fathers, and children dying at a rate of 1,000 a day. And now from the New York seropositivity number, we know that a devastating epidemic like that is enough to infect between 10 and 15 per cent of a population of that state. To get to a point where you have herd immunity, you would have to go through that repeatedly —probably four or five more times, because the attack rates go down as more and more people get immune. So if you want to replay that movie repeatedly in a misguided attempt to rapidly move toward reopening the economy, then that’s on the table. But it’s going to kill a lot of people and destroy a lot of lives. 

It’s surprising to me, given what people have been witnessing for the last six weeks in North America, that there are folks who are still coming out with bullshit like “this is just the flu.” It reminds me of Nineteen Eighty-Four, you know — you’re not supposed to believe the evidence of your eyes and ears. You don’t need mathematical models to tell you that this thing is a horror; you just need to turn on the news. So the responsible way forward is to follow the places that have done well. It requires competence, it requires resources, it requires organization, and it requires paying attention to what we’ve learned. But a lot of countries — Korea, Taiwan, Germany — have shown us that there really is a path forward, and we can incrementally open up our economy and get back to business. But we have to do it carefully and responsibly and not in a way that ensures the death of many of our loved ones. That’s not the way we do things. Ontario has been trying to ramp up its testing, heeding the lessons of those successful countries. What strikes you about the testing numbers and approaches this week? 

Fisman: Yeah, we’re getting there, aren’t we? We’re up around 10,000 tests a day, which is a far cry from where we were a couple of weeks ago. We’re getting there. More and more labs are doing the testing; the turnaround times seem to be getting shorter. In fact, I know they’re getting shorter, because I’m part of the provincial modelling group, and we have access to some data that lets one estimate that. The turnaround time has shrunk. What we need to do now, as we start to think about reopening the economy, is think about how we’re going to use testing for situational awareness and surveillance. 

We’re probably going to be using tests in different ways than we have been to date, because we’ve been mostly using them for clinical care. Now we’re starting to do more situational-awareness stuff. We started off in the nursing homes, where we really have no idea what’s going on. Now we’re testing broadly, thanks to Premier Ford, and we’re really learning about where this disease is and where it spreads. We need to expand that approach to places, particularly hospitals — Quebec is showing us right now how vulnerable hospitals can be — and we also need to expand that to include testing in the community for surveillance purposes. So we’re getting there, which is great. 

It’s like a shark: either you keep moving or you die. Ontario is moving. Would one have hoped to have been further along at this point? Of course. Would one have liked to have avoided the predictable errors we’ve made? Of course. But we are moving in a good direction. The reproduction number in the province is hovering at just about one — we need to push to get it below one and sustain it. Then we can focus on reopening the economy. 

Parenthetically, I would note that, in our modelling, the one province that really took a sharp turn over the last couple of days was Saskatchewan — which had been really well controlled and sustained, with a reproduction number below one. In the last couple of days, since they started talking about getting back to business there, the reproduction number has shot up. They don’t look like they’re in a position where they should be reopening anymore. But that’s obviously a decision for folks in Saskatchewan to make. You mentioned that you’re in the province’s modelling group. There was new modelling released this week — what does it tell us, and what have you learned through that work?

Fisman: Yeah, it’s great. What that group is all about is triangulation. You have some really bright folks, who I respect a ton, accessing the provincial data and comparing their results and insights. So you have folks from a number of different universities working together, but independently, and that allows Steini Brown — our chair, who did the presser this week — to sort of look at what everyone’s come up with and see what’s the same and what’s different. I think he was able to articulate that really nicely at this week’s press conference and say, “It looks like we’ve peaked and are going down the other side. Here’s what that looks like; here’s what the implications are; here’s where we’re still not doing as well as we might, particularly with institutional outbreaks.” I think that’s the way to do it. 

There’s a lot of uncertainty with infectious-disease modelling, but the fact that you have several different groups looking at these numbers and saying we’re at peak and going down the other side — that provides a degree of assurance to Steini and others who are in decision-making roles to say, “We’re not out of this yet, but we’re getting there, and we have to stick with it.” You’ve been critical this week of some of the province’s public-health authorities. How would you assess their approach and performance? 

Fisman: Well, from following me online, you know that I was pretty underwhelmed by the chief medical officer of health’s press conference yesterday. I’m growing a little bit weary of folks saying that they’re looking at science and making decisions based on science, and then not explaining what the science is that they’re referring to. You know, the CMOH talked this week about following the science in terms of not looking for infection in minimally symptomatic or asymptomatic individuals. Particularly in the context of institutional outbreaks, they’ve done a 180-degree about-face this week — I think because the premier has basically told them to do it. That’s very frustrating, because we’ve known for a number of weeks now that we miss a lot of infections. We’ve known for a number of weeks now that a disproportionate number of secondary infections come from unrecognized primary infections, which is what one would expect — you can’t do too much to prevent transmission if you don’t know you yourself are infected. 

So, on the one hand, it’s nice to see public-health authorities acknowledge that we do need to look for this in people that don’t feel sick, in order to protect vulnerable individuals like those in nursing homes. On the other hand, you sort of look at the about-face and some of the justification that went on at the press conference — which was fairly incoherent, to my mind — and all I can think is: congratulations, what took you so long? I’m glad they’re doing it, but I wish they’d done it a lot sooner. It would have saved a lot of lives. You’ve already mentioned the changes to testing approaches. What else will you be looking for in the next week? 

Fisman: I’m very curious to see when our sero-epidemiology results are going to start coming out. I know there’s a group working on this. I believe they’re working with Canadian Blood Services, which obviously has a lot of banked blood that we can use to test antibody in Canadians, and I’ll be looking forward to seeing how that matches up with some of the other efforts in Europe and Brazil and the United States now. That will be really important. 

It will also be really important to see how serologic testing starts to be used to identify individuals who are probably immune to infection and get them back to work — and use that as sort of an easy win as far as reopening the economy. It’s very important to understand immunity and how well antibody correlates with immunity. It’s not necessarily going to be one-to-one perfectly, but it’s highly likely that folks who have antibody are going to be protected. We need to figure out how to operationalize that as a province, in terms of getting immune folks back on the job, and we need to decide what the implications are. Do you still need to wear personal protective items when you’re interacting with COVID patients if you have high antibody titers? I don’t know. It will probably be too nuanced to do otherwise, but we can start thinking about how those folks might be able to function a bit differently in the workplace — in the health-care workplace and the essential workforce and the workforce as a whole. Thanks so much for taking the time this week

Fisman: Absolutely. Talk to you next week.

This interview has been condensed and edited for length and clarity. 

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