More users needed: Lessons from Alberta's coronavirus contact tracing app

Alberta's use of a smartphone app to help slow the spread of the coronavirus may provide other provinces with insight on what to do — and what to avoid — as Canada begins easing restrictions, heightening the need for effective contact tracing.

ABTraceTogether, launched late last week, is the first such app released by a provincial public health authority. An accompanying instructional video explains: "The more people who use the app, the safer everyone will be."

Early uptake figures and a key design quirk, however, illustrate how challenging it will be to ensure widespread adoption and efficacy in Alberta and elsewhere.

Contact tracing is the practice of identifying and notifying people at risk of contracting the virus from someone known to have been infected. Anyone who came in close contact with that person is instructed to self-isolate to avoid spreading the virus further.

So far, tracing in Canada has been done manually, with public health staff or volunteers getting in touch with each patient's recent contacts one by one. An app can speed up that process, and doesn't require users to remember where they've been or, just as importantly, with whom.

"If there's some way technology can help… we all want to get out of our houses," said Richard Lachman, a digital technology and culture researcher at Ryerson University in Toronto. But he warned against treating the software as a "panacea."

Alberta's app employs Bluetooth technology to determine with whom a user has spent time (at least 15 minutes in a 24-hour period). But it only works if everyone involved has the app running on their phone and Bluetooth enabled.

Early hurdles

As of Tuesday, ABTraceTogether had been downloaded just over 120,000 times, Alberta Health spokesperson Tom McMillan told CBC News. If each download accounts for a new user, that makes up less than three per cent of the province's population of around 4.4 million.

A group of British researchers suggested a similar app would only be effective if it were adopted by 56 per cent of the U.K.'s population.

McMillan declined to provide a target figure for Alberta, but said in an email, "Our goal is for as many Albertans to use it as possible."

Even users who've installed the app may have trouble using it effectively. Those running Apple's mobile operating system, iOS, are advised upon installation to "place your phone upside down or screen side down in your pocket" to keep their screen unlocked while out running essential errands.

An FAQ explains ABTraceTogether doesn't work properly when running in the background. In other words, it can't guarantee contact tracing continues while a user opens an email or replies to a text message. "If you need to use other apps, just remember to switch back" afterward, the FAQ states.

Alberta's health minister, Tyler Shandro, said Apple has been made aware of the issue.

"We're looking forward to the fix being able to make its way to the App Store as soon as possible," he said.

App developers are hopeful a rare joint project by Apple and Google will eventually allow them to streamline apps across iOS and Android devices, letting contact tracing run in the background and making the services more widely available.

How it works

While some previous contact tracing apps relied on GPS data, tracking a user's every movement, the Bluetooth method is emerging as a more accessible and less intrusive alternative.

James Petrie, a member of an international team developing a similar app called Covid Watch, said earlier iterations of the software focused on GPS tracking, but, "We hit a number of challenges — like how do you share this data between people without identifying them?"

A PhD candidate in applied mathematics at the University of Waterloo in Ontario, Petrie said Bluetooth provides more promise because of its ubiquity among smartphones and its ability for direct communication from one device to another.

That's how ABTraceTogether works. It was developed using the same code that formed the basis of Singapore's groundbreaking TraceTogether app. Deloitte and IBM were hired to tweak and rebrand the app for Alberta.

The software exchanges anonymous data with another user's device when it's located less than two metres away for several minutes. If someone with the app is diagnosed with COVID-19, they will be asked to consent for other users to be alerted and the information given to manual contact tracers, but the patient would remain anonymous. 

"Users will merely be informed that they have come into close contact with someone who has tested positive," said Dr. Deena Hinshaw, Alberta's chief medical officer of health. 

Unveiling the app last Friday, she took great pains to underscore its privacy features, such as how data remains encrypted on a user's phone and is only saved for 21 days.

"The use of technology for this purpose may seem intrusive, but downloading the app is completely voluntary and data will not be accessed unless a user provides consent to share their data with [Alberta Health Services]," she said.

Other provinces

Some other provinces have acknowledged they're considering how to implement digital contact tracing.

A New Brunswick government spokesperson said on Tuesday the province plans to implement an "anonymous privacy-by-design solution" using Bluetooth. Last week, New Brunswick's privacy commissioner said he expected Premier Blaine Higgs and others to be shown a demonstration of the app within 10 days.

Newfoundland and Labrador Health Minister John Haggie said earlier this week his province would ensure privacy is respected by seeking advice from experts on the topic.

British Columbia, however, is "not focusing on tracing apps such as these at this time," according to the Health Ministry.

The patchwork of plans leaves open the possibility that contact tracing apps will be incompatible from one jurisdiction to another, as interprovincial travel slowly resumes.

"It works really well if a lot of people can communicate with the same system," said Petrie, "so I'm hoping for Canada to see a national app, or at least to have provincial apps that can communicate, but I think that's still a few weeks or months out."

Ontario Premier Doug Ford has called for a national contact tracing strategy. Prime Minister Justin Trudeau, however, said on Radio-Canada talk show Tout le monde en parle he hasn't seen the right technology "so far."

Richard Lachman, an associate professor at Ryerson's RTA School of Media, pointed out, smartphone apps should only be seen as part of the solution to the ongoing crisis, along with other measures such adequate testing, physical distancing and widespread hand-washing.

"There are much bigger questions that will be required," he said, "and I don't want us to get distracted."