‘We can do this’: Epidemiologist David Fisman on ending Ontario’s pandemic

TVO.org speaks with the University of Toronto professor about school reopening, vaccination — and what the province can do to contain COVID-19 in the coming months
By Nathaniel Basen - Published on Feb 08, 2021
David Fisman is a professor of epidemiology at the University of Toronto’s Dalla Lana School of Public Health. (Courtesy of David Fisman)



In Ontario, COVID-19 cases are dropping, and vaccines are here. But so are new variants, and vaccine doses are arriving more slowly than many expected them to. Is this the beginning of the end of the pandemic? Or are things about to get a lot worse?

TVO.org spoke with epidemiologist David Fisman on Friday about opening schools, variants, vaccines — and how to end Ontario’s pandemic this summer.

TVO.org: How are you doing?

David Fisman: I'm doing all right. It’s been a long year.

TVO.org: I’m not sure there’s been a time like this yet in the pandemic. There’ve been a lot of legitimately great developments — cases are coming down, and vaccines are here. But there’s also potentially very bad news: more transmissible variants that are more resistant to vaccines. Where is Ontario in its pandemic?

Fisman: I’ve said it before, but pandemics have a beginning and a middle and an end. My best guess, and I don't have a crystal ball, is that we're past the middle now, and we're heading toward the end.

That doesn't mean it's smooth sailing all the way — we've still got a lot of challenges. As you say, cases do seem to be declining. Not only in Ontario, but actually across Canada and across the northern hemisphere. So we have a precipitous decline in cases globally. We've gone from around 600,000 or 700,000 counted cases a day a month ago to around 400,000 cases a day now. Global deaths have declined from 15,000 a day a few weeks ago down to about 10,000 a day — now, that's still a lot of people dying every day.

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It's the nature of epidemics that they don't just suddenly stop and drop: you have to go down the other side of the mountain. There's a degree of symmetry to that. So all the damage that's been done as the epidemic grew, there's a mirror image to that damage as the epidemic declines. But it's clearly in decline at the moment.

Good news in terms of vaccines: most of the vaccine candidates that were quick out of the blocks have actually turned out to be successful vaccines in less than a year, which is astounding to me. We now have at least four good vaccine candidates that are going to likely be available in Canada. Moderna and Pfizer are already in use. We have Johnson & Johnson, which is probably going to get approved soon: a single shot vaccine. And then we've got the Novavax vaccine — and the prime minister announcing support for new vaccine infrastructure in Canada, so we'll be making Novavax here. That’s fantastic.

We've had some possible vaccine misfires. I don't think anyone expected that something that came together this fast would be without any missteps. Supply-chain issues are a thing right now — that's probably going to get straightened out in the months ahead. The AstraZeneca vaccine has been a bit funny; the data are inconsistent in terms of protection of older people and in terms of whether or not that vaccine prevents transmission. But we wouldn't have expected all vaccine candidates to be to be successful, which is why I think the federal government's strategy of just buying broadly whatever they could get their hands on upfront was a brilliant strategy. It will serve us well in the months ahead.

I think they’ve taken unfair criticism around, you know, “Canada's hoarding vaccine” or “You bought this vaccine and not that vaccine.” They bought whatever they could get their hands on, knowing that there's a lot of uncertainty and that you might lose some of these vaccines moving forward.

It's like a Led Zeppelin song: good times, bad times. It’s a bit of a mix.

The current dark cloud on the horizon is novel variants, which is not a huge surprise: viruses mutate. Probably the most concerning questions around novel variants are, do they have an increased propensity to infect kids? That seems to have been the case in the United Kingdom in the fall. Do they have increased case fatality? There's some evidence in that direction from the U.K. And will they continue to change and become vaccine-escape mutants? Well, that's why we have to change our influenza vaccine every year or two, because that's what viruses do.

But in the months ahead, we're going to transition from this being a pandemic with very widespread susceptibility, to being an endemic disease, probably with seasonal outbreaks. As we get more Canadians immune, this is going to recede from the headlines and become a nasty virus to be sure — but one of many nasty viruses that we contend with every single year.

As someone said: We're at mile 18 of the marathon. We're tired, and we're not at the finish line. But we're getting there.

TVO.org: With some of the more complicated scientific studies that enter public consciousness, it can be difficult to determine the proper takeaway. For example, you’ll see that a variant might be up to X per cent more transmissible, and that a vaccine could be up to Y per cent less effective against it, but you might not know if that’s considered good or bad. Where do we stand right now on novel variants and vaccine efficacy?

David Fisman: For most of the vaccines that we'll be using in Canada, we actually have evidence — whether from neutralization assays in labs or from actual trial data. One of the neat things about both the Johnson & Johnson and the Novavax trials is they had arms in countries that have had issues with novel variants.

What we see is that there's apparently some reduced efficacy of the vaccines against novel variants. But when you're starting at 80 or 90 per cent efficacy, it can dwindle down a bit, and the vaccine will still be highly effective. I think that's the case for both Johnson & Johnson and Novavax.

Vaccines generally aren't a thing where it's one and done — you made your vaccines, and that's your vaccine in perpetuity. That's the case with things like influenza vaccine; that's the case with pneumococcal vaccine: vaccines change over time because they exert a form of selective pressure on pathogen populations. You're probably going to have to update the vaccines.

With mRNA vaccines, so that's Pfizer and Moderna, you can almost think of it as changing the cartridge. The vaccine platform itself, they can simply change around the mRNA molecule that they're manufacturing, and they can apparently turn that around in about six weeks. Because it's actually your body that's making the antigen — you're being given the recipe card with instructions that tell your body how to make viral proteins. That’s one of the huge leaps with the mRNA vaccines — we've gone from having to create and harvest pieces of living things to basically having a molecule like any other pharmaceutical, where you can change that molecule much faster. So that is encouraging.

TVO.org: You’ve stressed the importance of the rest of our pandemic response. Do you get the sense that we're focusing too much on the vaccines such that we're ignoring the other stuff?

Fisman: Oh, absolutely. Absolutely. And to a certain extent, the hypothetical availability of vaccines might have made things harder. I think folks at this point are thinking, ‘Well, I just need to muddle through this for the next few months. The vaccines are coming to save the day — we don't need to do the hard stuff anymore.’

It's going to take us a while to vaccinate. And what we're seeing, particularly in Israel right now, which increasingly has a highly vaccinated population, I think over 50 per cent vaccinated at this point: they're still struggling, because that society is not homogeneous. Particularly in the ultra-Orthodox communities there's been a lot of resistance to basic public-health measures. So on the one hand, they're creating a degree of herd immunity. But on the other hand, they continue to struggle with a lot of cases, because communities are mixing enough to dilute out the protective effect that the vaccine might have.

You also have to remember, none of these vaccines are 100 per cent effective. If you drive case numbers up and vaccinate the population, you're still exposing susceptible individuals to a much higher force of infection — which is a function of both the reproductive number of the pathogen and the number of infective cases in the population. If you have more people going around infecting, you're going to find the vaccine failures, right? If you have an 80 per cent effective vaccine, 20 per cent of the people who get that are still susceptible. If you have tons and tons of infectious cases, they're going to find those 20 per cent.

You need to be coming at this from both ends. You need to get your numbers down and vaccinate on top of that, and I think we will have a window to do that this summer in Canada. I don't want to use the F-word in an interview, but: vaccinate the F out of this thing over the summer, when cases are going to be subsiding, I believe, seasonally.

I'm very supportive of the federal government’s response. I think they've done a great job during difficult circumstances, and they're a bit hamstrung by the fact that health is a provincial matter in Canada.

But there was a lot of work that went into jumping the queue a bit on this small initial instalment of vaccine, and, to a certain extent, I think pushing out early doses of vaccine — which they knew weren't going to be very numerous — was laid out as something that might give people hope and encouragement. Instead, I think it's been twisted a little bit cynically and turned into ‘Oh, we have supply-chain issues.’ Nobody was expecting large amounts of vaccine until March. Because of the nature of these deals, where they've got multiple vaccines purchased from multiple companies, we're going to be awash in vaccine by summer. So what we really need to be doing is putting together the infrastructure and the systems, and using the systems already in place.

We vaccinate a couple of million people in Ontario very quickly for flu every fall. There are people who know how to do this. They do not, to the best of my knowledge, appear to be heavily involved in the current rollout of COVID vaccine in Ontario. What I hear, when I talk to people who are more on the inside of this stuff, is there's a lot of wrestling around turf right now. That's unhelpful. And that's where I think you need good leadership from the top.

We can do this, and we are going to have a great window of opportunity over the summer to largely snuff out COVID in Ontario — although I think it's going to persist as an endemic disease in places like congregate settings: long-term-care institutions, hospitals, jails, cruise ships. There’s a whole cruise ship division at the CDC for a reason.

The influenza pandemic of 1918 ended in 1919. There was the fourth wave in 1919, which was a small wave in the fall, and then it wasn't a pandemic anymore — it transitioned to seasonal flu. I think that's where we'll go with this.

TVO.org: Which groups, specifically, do you think should be more involved in this vaccine roll-out?

Fisman: It should be the folks who, year in year out, roll up their sleeves and do flu vaccines: our family doctors, public-health units, and pharmacies. I understand that you have to work with the hospitals when you're doing health-care workers up front, but in terms of who does vaccination of long-term-care facilities — usually that features heavy involvement of local public-health units and family doctors.

Moving forward, I think they need to get back to vaccinating older people living in the community, just as the Israelis did. Overwhelmingly, you should be prioritizing those over age 65. They're in sort of a double jeopardy, where on the one hand, they are the most likely to be severely affected if they get COVID. On the other hand, because you're over 65, you're more likely to be denied care when you need intensive care if the ICUs are full. There's a strong equity argument to be made for prioritizing community-dwelling older adults. I think the people to really focus on that are the public-health units, family docs, and pharmacists. Every fall, we have a very good flu-vaccine program in Ontario. It’s something to be proud of — use it.

TVO.org: You laid out, maybe not an end game, but a strategy we could use to effectively end Ontario’s pandemic in the summer. How do we get there?

Fisman: I think the learning curve for Ontario has been slower, perhaps, than one would have liked, but it's getting better. And I think the guy here who deserves a lot of credit is [the University of Toronto’s] Steini Brown, who has been extremely tenacious in pushing forward science as a basis for pandemic response. I think I think the command chain is still muddled; I still have some concerns about how policy is set. But we're in a much better place than we were six months ago, and good ideas are starting to move forward.

You see that there's increasingly an emphasis on transparency and reporting. Workplace outbreaks are now starting to be reported in Ontario: it's a year in. That's a great step forward. Surveillance is starting to improve. There is more receptivity to the use of rapid tests and more understanding of how rapid tests and rapid-test-based surveillance differs from clinical testing.

There's innovation like sewage testing, which is actually starting to come into its own in Ontario — that’s made a lot of progress as a surveillance methodology. I know that some health regions, like Ottawa, have started to talk about experimenting with backward contact tracing that involves QR readers. So you're not actually following cases forward; you're following them backwards to find out where they came from. Given the nature of this disease, with its over-distributed R, what you really want to find is, where was the super-spreader that created this case? Most cases are being created by super-spreader events, and to find those you have to look backwards. So that's great.

I think there's a painfully slow, but inexorable, changing of the position on the role of aerosol and the role of ventilation in protecting people. That's going to be really important for businesses. Things like conferences moving forward — if you have a highly vaccinated group of people in a well-ventilated space, sure, you can get back to having things like in-person conferences. You just need to be smart about it.

There's a fellow named Sandy White who actually led a group of private businesses into the rapid-testing space, which I think is fantastic. They got tired of waiting around for public-health authorities to say rapid testing is a good idea — we have evidence from around the world that rapid testing is a good idea. They're starting to work directly with companies to create test programs that keep workers safe in some of these big industrial settings or warehouses or places that have been disproportionately hit by this disease.

I think that's all to the good, when you have business people saying, “This is holding us back. And we're going to take the reins here a little bit.” There's a lot of good action going on.

The school stuff is weird, but I think it's important to remember that school stuff in Ontario was weird before we were in lockdown. The month before we locked down, teachers were on strike over class sizes. Is it surprising that we have class sizes emerging as a contentious issue during the pandemic? Probably not. I think what you have is a labour issue that's been distorted through the lens of a pandemic and disease prevention.

But even on schools, at this point, I agree with [Education Minister] Steven Lecce. The masking in schools has undoubtedly been helpful. It was incredibly contentious when it started: I think people have realized that that was a good thing to do, and it wasn't that big a deal for the kids. If you ever walked down the street after school gets out, you see the kids forget to take their masks off: they don't care.

They're talking about testing, although it's still a little bit unclear to me how they're going to use tests to keep schools safe. But there's been a lot of really good progress in Ontario.

I think there's increasingly the realization that this isn't about a choice between the economy and health: you get both or you get neither. When we have scary stuff and raging epidemics, and people being transferred 200 kilometres from one ICU to another because the ICUs are full in the GTA — this is not stuff that puts people at ease and makes them want to leave the house and spend. So I think that's been really helpful.

TVO.org: I’m a little surprised by your answer there. To a casual observer, it seems that, when schools open, cases go up, and when they’re closed, they go down. Maybe that’s inevitable, or maybe that’s resources and strategy — but you sound more optimistic about the school reopening than I imagined.

Fisman: I think we are okay to open schools advisedly. What I have been saying for a while is, schools are the one large gathering that's hard to close. Kids are overwhelmingly minimally affected by this disease, although we are seeing a surge in multi-system inflammatory syndrome in the U.K. now, with the new variants. That’s sort of the elephant in the room: we don't know what's going to happen with new variants. We see in other places that these new variants do seem better adapted to transmit among kids. So I think you have to do it step by step — you can do schools before businesses. To his credit, [Chief Medical Officer of Health David] Williams, I think yesterday, actually said we're going to open the schools, and then we're not going to move elsewhere on the economy until we see what happens. That's the way to do it.

There are reasons to be cautious. I don't think there's any evidence that the new variants have greater propensity to cause multi-system inflammatory syndrome. I think what you have in the U.K. is they've had a lot of kid cases. And as the denominator grows, the risk of the number of rare complications will grow.  

Rochelle Walensky — who's actually an old friend and the new director of the U.S. [Centers for Disease Control and Prevention] — has pointed out that we actually do know a lot about how to open schools safely. You need to use what you know. The pillars are masks, which we’re already doing in Ontario. Small class sizes — that's been a sticking point with the government. I don't think they should be digging their heels in on that, but they are.

Let's move beyond that. What else can we do? There's ventilation. You can't revamp HVAC systems in 60-year-old buildings in a month, on a on a dime. So that's got to be a longer-term project. What can you do in the shorter term? Well, you can use things like air cleaners, portable HEPA filters. You can use carbon-dioxide monitors to understand whether or not an indoor space is well ventilated.

The last pillar that the CDC has is benchmarks on when you should be opening schools in terms of community transmission. As you say, we do seem to see a surge in reproduction numbers from school. So the CDC actually has some case benchmarks, and, I think, actually, according to U.S. guidelines, most Ontario health units would not get a green light. Let's leave that aside — we're Canada; we're not the United States. But those are your guiding principles.

The other thing they've been doing a lot of in the U.S. is some form of surveillance testing. So, again, most kids who get this don't get sick, so you're not looking for sick kids so you can provide care. What you're looking for with surveillance testing in schools is basically an all-clear signal — you want to know that there's the absence of a problem. You don't need to test every kid every day to know that. What you need is some sort of stable, representative surveillance system that gives you a baseline when you first open schools, or, ideally, before you open schools. And then, over time, you watch that to see.

It’s like testing the chlorine in a swimming pool that says it’s okay to swim here. I think our public-health folks have struggled a little bit with that concept of turning this upside down — we're not case finding; we're actually looking for the absence of signal. You can find it in schools when there's nothing going on elsewhere, and you need to react to that, and that's how you keep out of trouble.

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

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