COVID-19: Last week today with epidemiologist David Fisman speaks with the University of Toronto professor about the testing, the numbers, and the outlook for Ontario
By Nathaniel Basen - Published on May 12, 2020
David Fisman is currently modelling the impacts of mask use on disease dynamics. (



David Fisman, a professor of epidemiology at the University of Toronto’s Dalla Lana School of Public Health, has been carefully tracking Ontario’s response to COVID-19. He’s also involved with the province’s coronavirus-modelling group. is checking in with Fisman on an ongoing basis to get his insights into the province’s fight against the coronavirus. We caught up with him on Monday evening. What do you see in the numbers this week?

David Fisman: We had an exciting week last week, with resurgences in Montreal and in Saskatchewan, with an outbreak in northern Saskatchewan. This week is looking a little bit happier: both of those local epidemics seems to be subsiding. The country as a whole has moved toward having a reproduction number that is pretty clearly below one, so we’re headed down the other side of the epidemic curve, which is great. Unfortunately, that means people are still getting infected, and some of those people will die, so this is not over. 

I think there are a lot of folks who are itching to declare victory and open things up again, which is a bit of a problem because the reason that infections are subsiding is because we have distancing in place. Looking ahead, I think we’re hopeful that we’ll start to see some economic revitalization happen, but it also seems like people are impatient about that. Predictably, as we reopen, we’ll see a resurgence of disease. That’s exactly what we see in Korea and Germany this week — two places that controlled their initial epidemic faster than we did and are moving toward revitalization. They’ve seen resurgences, just as Singapore did before them and just as Wuhan has this week. This is a really slippery foe, and this probably is a taste of what’s to come for a number of months yet. One of the major themes from the past week was inconsistent testing numbers. Most notably, Premier Ford called out certain local medical officers of health for holding the province back. What do you make of the province’s testing capacity at the moment?

Fisman: Ontario’s capacity to test is now very good — the province has shown that it can churn through 16,000 specimens a day, which is remarkable and very far from where we were a month ago. That’s tremendous. I’m not an insider on this, but it certainly does seem like the premier is getting some pushback from some individual medical officers of health and some individual public-health units. That’s unhelpful, and I understand his frustration. 

He’s taken that pushback and moved it in an interesting direction. The premier has, for a long time, said that he wants to integrate and amalgamate Ontario’s public-health units. He’s sort of turned these instances of poor leadership on the part of a small minority of medical officers of health into an argument for — if I understand his remarks correctly — pushing ahead with amalgamation. My read on that is that it’s an unfortunate take. 

When I look at the situation in Ontario, I see 34 health units, most of which have outperformed the leadership coming from the province. You have places like Kingston that haven’t had a single long-term-care outbreak. You have Toronto — dealing with a very tough hand in terms of the size of the city and the available resources — doing a remarkable job on contact tracing, notwithstanding that they have tremendous numbers of cases. You see that all around the GTA. You see that in Ottawa as well. You see that in Sudbury. Really excellent leadership from local public-health units. 

At the provincial level, I continue to really have concerns about muddled messaging coming from the chief medical officer of health — a lack of messaging that reflects the evolving understanding of COVID. To me, when I look at this situation, I’m thinking, wow, thank god we haven’t amalgamated these public-health units yet. Thank god we have these public-health units that can shine. Public health is a fundamentally local discipline. Thank goodness not everyone is under the direct supervision of the province, because the province has lagged on a lot of the creativity and professionalism that we’ve seen from local public-health units. 

So I understand the premier’s frustration, but the direction in which he’s channeling it is, to me, not a helpful one. We spoke a lot last week about this grand experiment in Quebec and Ontario. You mentioned that Montreal has had some problems since then, and Quebec’s government has had to reconsider its plans. What have you noticed? 

Fisman: Oh, yeah, I think that Premier Legault was starting to get a bit of pushback. To circle back to Premier Ford’s initial messaging saying that this is a “roadmap not a calendar”: I think that was excellent and right on. Premier Legault has somewhat tied himself to a timeline because of the way in which they rolled out their reopening strategy. There was a sort of news dump over the weekend in Quebec. I’m not sure who released these internal modelling projections, but, clearly, the modellers working on this in Quebec have warned about the potential for resurgence with overly optimistic reopening. 

To me, the most interesting thing, which I think they’re still pushing ahead with, is the reopening of schools outside Montreal — which I believe starts this week. For those of us who have been really concerned about the possibility that children may be important vectors of this disease, they’ve essentially created a natural experiment, because Ontario is keeping schools closed. It’s not in isolation, there are other moving parts, but I think if we see a sudden resurgence — and sudden with this disease means over the next two or three weeks — in Quebec but not Ontario, I think that will be the result of an interesting natural experiment. 

I continue to be concerned that there hasn’t been enough attention given to epidemiology in kids. I know folks are starting to study that in Germany and Switzerland, but we haven’t really studied it in North America. School is one mass gathering that’s really, really hard to suspend given the centrality of being able to send kids to school: for their social and intellectual development and for economic recovery, because it allows parents to work. It amazes me that we’re not doing more of a full-court press in terms of studying this disease in kids. There are ways to do it even with kids not back in school — for example, looking at serology in children — and I haven’t seen any research initiatives like that so far in Canada. Ontario is opening somewhat, though — there’s curbside pickup for retail stores; provincial parks are reopening for daytime use. Does any of that concern you? 

Fisman: That all strikes me as pretty innocuous. I think as long as folks maintain distancing, none of that has to do with large indoor gatherings, which have really been the hallmarks of resurgence. Korea, which has been incredible, has a resurgence this week that’s focused on a large downtown nightclub, I think in Seoul. That’s very different from having people come pick stuff up from stores on curbsides or safely using parks. I think everyone needs a bit of mental respite at this point, so I think those measures are entirely reasonable and aren’t the kinds of things that have caused this disease to resurge elsewhere. What will you watching for in the coming week?

Fisman: Well, our group is being a bit inward looking in the coming week because we’re trying to get some research done. The research group I work with has three major projects: I’ve been working on masking; my colleague Ashleigh Tuite has been working on contact-tracing modelling; and my colleague Amy Greer has been working on safe opening of congregate settings, like summer camps and dorms. Her focus is specifically on summer camps, but the kind of modelling she’s doing can potentially be extended forward to things like university dorms. I think Amy’s idea is, when you take people of a certain age group —  be they kids going to camp or young adults going to dorms — out of the community, mix them together, and then re-disperse them back home at some point, what does that do to the dynamics of the epidemic? It’s really interesting stuff. My sister works in summer camps, and she’s been trying to figure out what they can offer this year. I’m sure she’ll be looking forward to reading that work. 

Fisman: Or maybe not. Look, it’s not the end of the world. I’ve been saying this to people for months now: we don’t look back on 1918 as the year the world ended. We look back at 1918 as the year World War I ended, and, by the way, there was a terrible pandemic that was very destructive and killed a lot of people. In five years time, this is going to be a bad memory. The world will have moved on. Hopefully, we will have learned enough from this that we’ll have started changing some of the things that created the vulnerability for a situation like this: how we interact with our physical environment, how we treat animals and use animals for food, how we ignore public health and vaccine development when issues aren’t front and centre. We’ll see in five years if we’ve learned anything from this, but I think we’ll have moved past this. This is a very tough time, but it’s also not the end of the world. And your work is in modelling the impact of mask use? 

Fisman: Yeah, exactly. Without getting all nerdy on you, we use something called next-generation matrices to look at the impact. Masks act in two directions: they prevent transmission and they prevent acquisition — we think. There’s a lot of controversy as to how effective they might be, so I’ve been working on some stuff that suggests that poorly effective masks, used widely, could still make a really big difference in disease dynamics, especially if we have a reproduction number that’s close to one. So if we’re just about below one but can’t quite seal the deal — which has been the case in Ontario for about three weeks now — could widespread masking be the factor that tips us over, even if the masks aren’t that good? The answer is yes, of course it could. I’ve been thinking a bit about epidemiology as a field of study. On the one hand, researchers have had to leave what they were doing to focus on COVID-19. On the other, there has perhaps never been this much enthusiasm about the field. What will the lasting impact be? 

Fisman: It’s really hard to know when you’re in it. I think, for me, what will be interesting is to see if we’re dealing with a larger applicant pool for the school of public health at U of T. Does this become something that is so exciting and so interesting that students are beating down the doors wanting these skills? I think that’s possible. Certainly now, in May 2020, the joke in epidemiology is that we finally reached the point where people don’t think we work on something that has to do with skin — which is a big change for us. We’ll see where it goes. I can’t predict the contours of the epidemic over the long term, and I can’t predict what this will do to our field long-term. 

I’m a bit ambivalent, because right now we have these amazing students who are in it because they really care about people. They love this stuff. I hope the field doesn’t move in a direction where we’re attracting students who are more into the numbers than they are into the human beings behind the numbers. You see a little bit of that, you know — the internet joke is the “armchair epidemiologists,” people who are into this because they’re quants who aren’t going to their day job so they’re going to geek out on something else. 

The core of public health is really equity. It’s ensuring that everyone in a population is as healthy as they can possibly be. It’s difficult for me to imagine that the field will remain quite as interesting to some of the people who have jumped aboard during this crisis once it’s more about the health of others and less about the health of you. I think that if that is the case, then that will be to the benefit of the field, because the folks who come to epidemiology now are pretty special people. With those quantitative skills, they could go work in fintech, or something like that, but they choose to work in public health. I hope we don’t lose that. I hope we don’t lose that spirit of people wanting to work on this stuff because they care about other people. 

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

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