Contact tracing crucial to contain new COVID-19 outbreaks during relaunch, experts say

As more and more Albertans resume normal activities, experts say contact tracing will become more complicated — and even more important.

Alberta's contact tracing team included roughly 400 investigators at the height of the COVID-19 pandemic. The team has contacted close to 23,000 Albertans since Feb. 1.

With fewer daily cases accumulating now, the team is roughly half its peak size. But it's prepared to ramp back up if it becomes necessary, officials say. 

Dr. Richelle Schindler, a medical officer of health in Calgary, says that during the lockdown — when people had very little social contact — one investigator would take about a day to conduct contact tracing for one case.

"It's a lot of sleuthing," she said.

Contact tracing is about identifying, informing and monitoring people who might have come in contact with a person who has been diagnosed with an infectious disease, such as COVID-19.  

It starts with a positive test. Public health officials then want to know whom that person might have inadvertently infected. 

The next step is tracking down anyone that person had prolonged contact with in the past 14 days, so they can be informed they might have been infected and take measures to quarantine and be monitored for symptoms.

In early days of the pandemic — before lockdown restrictions came into force — it could take up to 10 investigators to conduct a full trace.

"That's why it's so important even as we continue to reopen that everyone continues to be careful … that everyone continues to take these steps to mitigate the risk of spread of COVID because that allows us to stay on top of the amount of work it takes to conduct contact tracing," said Schindler.

University of Calgary infectious disease expert Dr. Craig Jenne says contact tracing is critical to contain clusters as Alberta moves through relaunch.

"It absolutely takes on a greater significance," he said.

"As we reopen and people resume more activities, the number of people they've contacted — and likely do not know — becomes longer and longer and longer, and that makes the contact tracing process more and more difficult."

Jenne says Alberta's mobile contact tracing app could make that easier.

So far, just over 200,000 Albertans have signed up for the app, which users download on their cellphones so that they are alerted if they have come into contact with someone who has tested positive for the COVID-19.

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.

And on Thursday, Prime Minister Justin Trudeau said a national app is coming soon. Its development is led by the Canadian Digital Service, a government initiative connecting departments with startups, with help from Shopify, BlackBerry and the Ontario government.