Contact tracers are the new front line against COVID-19

As Canada reopens, our economic recovery rests on their efforts. No pressure, there.

Tracey Ashby spends most of her day on the phone ringing up strangers, and she’s seldom calling with good news.

Ashby works in case and contact management for the Middlesex-London Health Unit in southwestern Ontario, and those hearing her voice for the first time are likely getting the call for one of two reasons. Either they’ve been in close contact with someone who tested positive for COVID-19, and must self-isolate for at least two weeks, or she has the results from a recent COVID-19 test that came back positive—which was the case when she got 25-year-old Siamak Keshtpour on the line in early June.

Keshtpour, a University of Western Ontario grad student, had been self-isolating for a few days after receiving a call from one of Ashby’s colleagues warning him he’d been in contact with someone who had COVID-19. Soon after, he developed a headache and tightness in his chest, so he had a hunch about what might be going on. Still, the news landed as a shock.

Ashby asked him about his symptoms, his living arrangements and how he would manage in quarantine. Keshtpour, who later spoke to Maclean’s, recalls telling her he’d had colds that felt worse, and that he would have groceries delivered. Then, though she doesn’t frame it so, Ashby asked him to take part in a mental exercise vital not only to the health of his loved ones but to the economic recovery that tens of millions of Canadians keenly await: would he disclose the name of every single person with whom he had been in close contact, starting days before his symptoms started to develop?

READ: Quarantine nation: Inside the lockdown that will change Canada forever

Keshtpour was happy to co-operate, saying later: “That was my biggest concern. I didn’t want to give it to someone else. I knew I might be okay, but other people might not be.” He gave Ashby a list of people he’d seen—less than a handful—along with their contact information. More strangers for Ashby to call with a bit of bad news.

Ashby is among Canada’s growing army of thousands contact tracers who hold one of the keys to society’s successful reopening. In 11-hour shifts that can veer from breezy to fraught with tension, they take on the roles of investigators, teachers, therapists and confidantes. For most people they call, they’ll only ever be a voice on the phone. For the country as a whole, they form an invisible, defensive line to ensure the coronavirus doesn’t get a renewed foothold and start spreading like wildfire.

There’s never really a positive way to spin the news that someone can’t go buy food, drop by the office or get some fresh air with a walk around the neighbourhood. Depending on their living circumstances, COVID carriers might have to retreat to quarantine in their basements or another section of their homes, walled off from family or roommates.

Yet contact tracers are also voices of reassurance: they check in every few days to see how people are doing, gauging if medical attention is needed, offering help with those struggling to get food or medication in quarantine and—vitally—tracking down every person who had been in close vicinity of the person with the virus.

When strict social-distancing guidelines are in place, and people abide by them, a contact tracer’s job is easier: such efforts result in fewer total cases, and those who do test positive don’t have as many relatives, colleagues or friends to track down. But as Canadians demonstrate a growing impatience for physical-distancing restrictions—rationalizing weekend visits with mom and dad; hosting backyard barbecues with friends; joining the masses at parks—tracers must expand their burgeoning Rolodexes.

Since time is of utmost importance in tracking each contact, and few carriers know the people behind them in the grocery line, several provinces are augmenting the process with COVID-tracing apps—some with the help of tech giants Google and Apple—which have the ability to automatically alert someone if they’ve been in contact with a positive case.

READ: These charts show how our fight to ‘flatten the curve’ is going

But an app isn’t equipped to help with the emotional toll on someone finding out they might be carrying a potentially fatal virus. Ashby, who in normal times works in reproductive health, has at least basic training to counsel them through that trauma. Some people weep when they find out they’ve tested positive, asking if it’s possible they might die. Relatives of one COVID carrier were so displeased by news of a positive test within the family that one of them berated Ashby over the phone until she cried.

Others who have been in contact with an infected person will curtly ask Ashby: “What do you mean I’ve been exposed? Who was it? I need to know.” Privacy rules block her from disclosing that information; she can only tell them the date the contact occurred.

“It’s one thing to get swabbed and anticipate a negative or positive test, but to get a call out of the blue that you’ve been exposed—and to have no idea where it’s coming from—there’s a lot of anger,” Ashby says. “Unfortunately, we bear the brunt of that.

“One woman told me, ‘This isn’t fair! You’re telling me I can’t watch TV if I have to be in the other room,’ ” she recalls. “I had to tell her: ‘It’s not about fairness. It’s about a pandemic.’ ”


Alex Summers, an associate medical officer of health with the Middlesex-London Health Unit, uses a sports analogy to compare ways of curbing the virus. Physical distancing is like a zone defence, he says, while contact tracing is more man-to-man coverage. As cities loosen up their zone defences—allowing people to gather in larger numbers, visit barber shops or head into the office—the man-to-man defence of contact tracing must get tighter, Summers says.

Which is to say, if Canada wants effective contact tracing for nearly 38 million people, the country is going to need to sign up more people to play defence. Last year, before COVID-19 arrived, Alberta Health Services (AHS) had about 30 employees working year-round on contact tracing—mostly following up on cases of measles or sexually transmitted infections. But when the coronavirus started to spread, the province’s lone health authority quickly exhausted the capacity of this core team. Public health workers were redeployed. When medical schools shut down, AHS recruited students for on-the-spot training. “They were pretty critical to our response,” says David Strong, a medical officer of health with AHS, “but it’s not sustainable.” The students, after all, will eventually go back to school.

An area of the Middlesex-London Health Unit that has been sectioned off for social distancing (Photograph by Nathan Cyprys)

An area of the Middlesex-London Health Unit that has been sectioned off for social distancing (Photograph by Nathan Cyprys)

Alberta Health Services is in the process of hiring 64 people dedicated to coronavirus case management and contact tracing, and, if there’s another surge, will redeploy COVID-trained staff currently working in other sectors of public health. “We’re aiming to have a workforce that can handle about 350 cases per day,” Strong says, a scenario that would require 150 contact tracers on the job each day—and about 400 staff in total if the expectation is they’re covering 16 hours of phone calls every day of the week.

In Toronto, officials sought out those with public health or nursing backgrounds who could guide a conversation with minimum supervision, says Omar Ozaldin, manager of communicable disease control for Toronto Public Health. They received training in the basics of COVID-19, along with best practices in establishing trust and steering conversations for the purpose of collecting information. Then they spent time shadowing experienced investigators. Ozaldin describes the work as both “an art and a science,” explaining: “You can learn the epidemiology and contact-tracing process based on your medical background, but then it’s an art communicating to people clearly.”

Toronto’s team has grown during the pandemic from its original core of about 100 to about 700. Ozaldin figures they’ll have to ramp up further when social measures are relaxed.

But with COVID-19, it’s tough to predict which jurisdiction across the country will have an outbreak requiring more contact tracers than the local public health unit has on hand. Nearly 54,000 people registered for a volunteer recruitment program set up by the federal government, with the idea that they could provide, among other services, contact tracing to provinces and territories that needed them. What’s more, few outside the public health field understand the nature of the work. In March, Statistics Canada identified up to 1,700 of its field survey interviewers, with collective proficiency in more than 35 languages, whom the federal government estimated could conduct 600,000 contact-tracing calls per month. But those who do the work now say that’s unrealistic: initial case interviews can last more than an hour, while routine check-ins can last 15 minutes.

“I’m not just calling for a temperature check,” adds Sheila Montague, a nurse who handled case and contact management for the first COVID-19 case in London, Ont. It’s about establishing mutual trust to make sure people abide by self-isolation rules, she says, and patience and attention to tone are essential: “The minute you start to preach, you lose them. And if you start to get angry with them, they won’t pick up the phone.”

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The stakes can escalate with devastating speed. Ashby recalls one call with a woman in her 60s, in which she could hear over the phone that the woman was having a hard time catching her breath. Ashby urged her to get to a hospital and offered to arrange transportation. The woman didn’t want to go, so Ashby said she’d put her in touch with an urgent-care clinic, while imploring the patient to go to hospital if her symptoms worsened. The woman did so soon after, but her condition continued to deteriorate over the next few weeks and she died.

Ashby took the news hard. “I sit on a reproductive health team and coordinate a prenatal program for women at risk of food insecurity,” she says of her regular job in public health, before she was reassigned for the pandemic. “We don’t deal with death.”

It’s mid-May in London, and the region’s load of new cases hovers around two or three a day, an encouraging trend. Then, on the morning of May 18: nine. What could explain the bump? Look at the calendar, and work back in time.

Consider a COVID-19 case that travels the following (quite typical) arc: five days after contracting the virus, the patient starts to experience symptoms; a couple of days pass before that person gets tested, and still another before the result is available. Rewind eight days and you’re at Mother’s Day.

At the end of May, there is another mini-spike—eight new cases in one day and 11 the next, marking the region’s highest count in back-to-back days in over a month. Count back again and you land on the Victoria Day weekend. People are clearly gathering in groups without proper social distancing. The contact tracers have more phone calls to make.

Public health units in Ontario have set a benchmark of reaching 90 per cent of contacts within 24 hours of when they are notified of a case, a target that 80 per cent of the province’s 36 units were meeting by the end of May. Every minute counts, but even if contact-tracing teams reach their targets, there are forces outside their control that influence the spread of the virus.

In Toronto, for instance, people were waiting nearly five days on average from symptom onset before going in to get tested. In Middlesex-London, three days might pass before testing swabs got through the lab and results reached the contact-tracing team. In Montreal, staff had to take the archaic step of faxing individual lab reports to the regional public health department, where a clerk would type each result into a database. Only then could the contact tracers get to work.

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Of the situation in London, Summers says: “If someone gets tested the first day they have symptoms, it’ll be four days before all their contacts are called. That’s as good as it’s going to get. What we can’t control is how quickly people present for testing, and if we can reach your contacts.”

Nor can they control how many close contacts each case presents. Tracers in Summers’s unit have chased, on average, 12 contacts per infected person since their first was reported. Ashby’s personal record is 29—though that was before Ontario went into lockdown. Vancouver’s count varies immensely, from one to 55, according to Vancouver Coastal Health, not including major outbreaks.

But when people are staying at home, as many were in Ontario in late May, those averages fall sharply. The 862 cases reported to Toronto Public Health between May 18 and 24 averaged one close contact requiring follow-up. Ozaldin, the manager of communicable disease control, credits physical distancing. Conversely, he says, “as the government loosens up restrictions, I have to work that much more.”

How much, exactly? Researchers from the United Kingdom’s London School of Hygiene and Tropical Medicine measured the effectiveness of isolation, testing, contact tracing and physical distancing in controlling the spread of COVID. Using their models, University of Toronto epidemiologist and math modeller Ashleigh Tuite—who was not part of the study—set out to determine what it might take to keep Ontario’s COVID-19 reproductive rate below one, even as distancing measures are relaxed. (A reproductive rate lower than one means each positive case is spreading the virus on average to fewer than one person, leading to the pathogen’s slow eradication.)

Tuite found that even if restrictions are loosened slightly from the days when non-essential workplaces were shut, keeping the spread rate below one would require a majority of symptomatic cases to be discovered through testing, and all known contacts to be traced before they themselves became infectious. For those anticipating the return of live music concerts and bustling workplaces, it’s a splash of cold reality.

“Most of the impact we have right now is due to physical-distancing measures,” Tuite says. “As we start to dial those back, how much testing we’re doing is really important. The focus on efficient contact tracing is a little misplaced right now. It’s important. But if we’re not finding enough initial symptomatic cases, being really good at contact tracing isn’t really going to help.” For that reason, Tuite calls efficient contact tracing “the cherry on top” of a good system for controlling the spread of the virus: without widespread testing, it won’t make much of a difference.

A swab testing kit; how quickly COVID tests are processed is a factor in how effective tracers can be (Photograph by Nathan Cyprys)

A swab testing kit; how quickly COVID tests are processed is a factor in how effective tracers can be (Photograph by Nathan Cyprys)

There is, however, debate as to just how much testing is appropriate—or feasible. “Here’s how we don’t find cases: we don’t go out and randomly test a million people in B.C., because that would be a million tests and almost all of them would be negative and it’d be a tremendous waste of money, time, resources,” says Caroline Colijn, a professor at Simon Fraser University and the Canada 150 Research Chair in Mathematics for Evolution, Infection and Public Health. “Modellers like me might like that data. But the best way to find cases is to see who is linked to cases you’ve already found.”

Still, as adults return to the workplace and kids to schools or daycares, there’s an added challenge in identifying every person an infected party has been in contact with, as opposed to those merely known to the person who tests positive. If workplaces reopen and public activities resume, then 60 per cent of exposed contacts—known or unknown to the coronavirus-positive person—would need to be traced and isolated in order to avoid a rebound, according to a recent York University study. If schools reopen as well, that number rises to 70 per cent. “In terms of the economy, that would be hard to achieve,” says Jane Heffernan, one of the study’s co-authors and director of York’s Centre for Disease Modelling. “People need to go to work.” Indeed, if 70 per cent of all people exposed need to go into self-isolation, a single case could force the shutdown of many essential workplaces.

A study published recently in the Lancet reached similar conclusions, finding that 75 per cent of infected contacts would need to go into quarantine within 12 hours to contain a potential outbreak. “If you can’t get to three-quarters of contacts in 12 hours, you’re back at square one,” says Chris Bauch, a mathematics professor at the University of Waterloo, who published an accompanying commentary in the Lancet asking, “When should quarantine be enforced?” That’s why Bauch recommends trying digital strategies, such as contact-tracing apps. “The problem with physical contact tracing is people forget stuff or they don’t know who that person was.”


A contact-tracing milestone occurred in Alberta in late May. The province’s COVID-19 app, ABTraceTogether, had its first reported instance of someone uploading a positive COVID-19 test result that led contact tracers to discover another case of coronavirus.

ABTraceTogether uses Bluetooth technology so that when two people using the tracing app are within two metres of each other for a cumulative 15 minutes, the phones will exchange data via an “encrypted digital handshake,” as Alberta’s chief medical officer of health, Deena Hinshaw, put it. Then, if one of those people later tests positive, the app knows. The people exposed could be strangers to the infected person—passengers sitting near her on a bus, say, who fall through the cracks of manual contact tracing.

It’s one of several ways apps can augment traditional tracing, says Jia Hu, a medical officer of health with Alberta Health Services, who notes that “some people don’t pick up the phone, especially from a strange number. With instantaneous alerts, you don’t have to wait for a phone call.”

So tracing apps can get the message out faster, warning potential carriers of the virus that they need to self-isolate and perhaps get tested. That, in theory, saves public health teams having to drastically ramp up their numbers of contact tracers.

But apps only work as long as lots of people are willing to use them. A month after its launch on May 1, the Alberta app had about 200,000 registered users, representing about four per cent of the population.

So how many people using the app have tested positive for COVID-19? How many people have been told to go into self-isolation who might otherwise have been missed by manual contact tracing? How many confirmed cases of COVID-19 have been traced thanks in part to the app? “We are not providing ongoing updates on case numbers from the app specifically, as this is interwoven into our ongoing contact-tracing work,” says Alberta Health spokesperson Tom McMillan.

Without going into specifics, Niraj Dalmia, a health-care artificial intelligence lead at Deloitte Canada working with Alberta on its tracing app, told Maclean’s the numbers of contacts notified are very low. That’s not necessarily bad news: in Australia, more than 6.2 million people had downloaded the COVIDSafe app promoted by the government—about 25 per cent of the population—but after seven weeks of use, the app hadn’t identified a single contact. The Aussie government says that’s a testament to the country’s low daily case numbers.

Alberta’s daily tally of new COVID-19 cases hadn’t exceeded 53 since mid-May, and Hu expects the app to be more useful as the province reopens. “Until we have a vaccine, we’ll have to do something, and I don’t want us to be distancing for the next two years.”

On July 2, Ontario will roll out its own tracing app, one that Prime Minister Justin Trudeau hopes will be adopted by the other provinces and territories, and one he said will be most effective if many Canadians download it. “There are over 30 million smartphones that could take this app in Canada,” he noted, “so we can talk about a significant portion of the Canadian population that could be protected by this app.”

Whether governments can overcome privacy concerns surrounding voluntary apps remains an open question. Ottawa worked closely with Apple and Google as the tech giants launched a partnership to help build coronavirus exposure software, and Trudeau stressed the new federally approved app will not run on location services or geotagging of any sort.

Hu, meanwhile, insists the problem is one of public perception: “People are willing to give their data to Google maps, but they aren’t used to giving a small amount of data to health authorities because it has undertones of government surveillance.” Alberta’s tracing app, he adds, collects only phone numbers—not location, a user’s age or anything that might set off red flags for those worried about privacy.

Ann Cavoukian, executive director of Ryerson University’s Global Privacy and Security by Design Centre, describes the Apple-Google software framework as “amazing,” adding she discussed privacy issues with the team at Apple. A former privacy commissioner of Ontario, Cavoukian says she’d use an app in its original framework from Apple-Google. But she acknowledges her fear that “public health authorities will want to reach much further to get data.”

As a result, Cavoukian is calling for sunset clauses on government use of tracing apps and the data they yield. “You need something to put a firm stop to this when this pandemic ends, which it will,” she says. “I have no faith in the government holding itself back and returning the additional powers it’s obtained during this period.”

Cavoukian’s not the only one, and if the apps are going to serve their purpose, governments may have to work hard to alleviate Big Brother fears. An Oxford University study found 80 per cent of smartphone users would have to use a tracing app in order to suppress the epidemic. The study assumed that people older than 70—who are more vulnerable to COVID-19 and less likely to use smartphones—would be under a partial lockdown, and that people under 10 don’t have smartphones. Under these conditions, 56 per cent of the U.K.’s overall population would need to use the app to halt the virus. Says Summers, from Middlesex-London’s health unit in Ontario: “It’s an impossibly high number.”

The last phone call for a contact tracer is often the best: the chance to tell someone their incarceration is over. Some let out a “woo-hoo.” Others take it in stride. Montague, the London nurse, develops such deep connections with some people that a few stay in touch even after getting the all-clear. Her colleagues jokingly ask how many weddings she’s been invited to. (It’s more than one.)

But the more case counts go down, the more people feel they can go out and meet with others, potentially keeping the virus going. Many tracers feel a heavy onus to keep it from spreading. “Generally, we are unsung heroes. Nobody usually thinks of us,” says Ozaldin at Toronto Public Health. “This is the first time we’re on the public’s radar.”

One of Ashby’s colleagues gave the final call to Keshtpour. She checked on his symptoms and, as he was back to normal, let him know he was free to leave home. And Ashby, who was so invested in Keshtpour’s well-being during his quarantine, likely won’t ever speak to him again. For all involved, that’s the good news.

Editor’s note:

We hope you enjoyed reading this article, and that it added to your understanding of the ordinary and extraordinary ways Canadians are staring down this pandemic.

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Alison Uncles
Editor-in-Chief, Maclean’s

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