'At the brink': Dire warnings as B.C. contact tracers nearly overwhelmed
VANCOUVER -- Once held up as a shining example of how a populous province can keep COVID-19 infections low, British Columbia has now seen infections balloon to the point that the province’s contact tracing system may soon be overwhelmed and ineffective.
On Thursday, the province’s top doctor acknowledged contact tracers are “at the brink” of not being able to keep up with infections, having said last week that tracers were “reaching (their) limits.”
“We are watching very carefully our ability to find people quickly and that has been challenged, particularly in the Lower Mainland health authorities, where we have had so many cases per day it’s been a challenge for us to find people, to find their contact in a safe and quick way, being able to follow up and stop clusters before they grow into larger outbreaks,” said provincial health officer Dr. Bonnie Henry, who noted they’re following a metric to gauge effectiveness. “And so we’re on the brink with that and that is the area that I am most concerned about.”
A UBC professor modelling the infections and B.C.’s ability to keep up is warning it’s not looking good.
“Contact tracing, what we find in the models is it works really well when the numbers are low and that makes sense because contactors can call all the people on the list and reach them early on in their disease and tell them to self-isolate, but there’s this kind of critical point – we call it the tipping point – above which if we ever get above that number, the contact tracers can’t keep up with the growing number of cases — they can’t call that many people,” said biomathematician Sally Otto. “I don’t know exactly where this number is, this tipping point is in British Columbia, but we saw Toronto passed that number where they said, ‘We’re flooded, we can’t keep up with the number of calls, we need to focus our contact tracing efforts where they’re most helpful.’”
Otto says until the numbers go back down to manageable levels again, contact tracing isn’t much help because its efficacy is in quickly contacting those who could be infected and having them self-isolate to avoid infecting others before they know they’re sick.
“Timing is hugely important,” she said. “If contact tracing just reaches the contacts 14 days after their infection it’s as if it didn’t happen at all, so you need to reach them early in the infection.”
On Thursday, Health Minister Adrian Dix said health authorities are continuing to hire more contact tracers.
“An increase of 66 from the last week, 434 in the interview stage, and 102 more in the offer stage,” he said. “We are also funding culturally sensitive contact tracing supports for 76 positions for the First Nations Health Authority — that’s more than 1,000 people.”
A Canada-wide issue
Experts first raised the alarm about an overwhelmed system across the country last month as Toronto halted contact tracing efforts in the face of exploding case counts, a move local officials describe as temporary until they can get infection numbers back under control. They are still struggling to resume full tracing efforts.
In Alberta, the contact tracing system has become so overloaded that the province’s top doctor has advised those who test positive that their diagnosis will come from health officials, but they should notify their close contacts of their status themselves or through an automated app.
The Prime Minister and Canada’s top doctor have urged the public to download a national COVID-19 notification app, but B.C. has declined to participate in the effort. Alberta has also rejected the national app, but has a provincial notification app that’s only notified a few dozen of the many thousands infected.
Tracers have uncovered major infection sources
At a press conference last week, Henry outlined several scenarios in which contact tracers determined a single contact was responsible for many more infections. For example, one person at an industrial site ended up causing 48 cases in total.
Otto is urging people to reconsider their lifestyles and buckle down so if they do get a call from contact tracers, they can do so quickly with only a handful of people to call.
“Really ratchet back all of our activities right now, get these numbers back down so that we don’t overwhelm the contact tracing system,” she said. “If we overwhelm the contact tracing system what we see is if we’re able to suppress the numbers and reduce this ‘R’ – the number of new cases per case – while the numbers are low, once we get above there all the help that contact tracing does for us basically evaporates.”