How Quebec is finally using rapid testing to screen for COVID-19

The Quebec government began taking deliveryof hundreds of thousands of rapid tests for COVID-19 earlier this fall, but it hasn'tdeployed them in large numbers until now.

Thousands of test kitswill arrive in the SaguenayLac-Saint-Jean region on Friday, according to the Health Ministry. Regional public health officials will begin using them as part of their screening efforts sometimein mid-December.

The tests, which return a result in as little as 15 minutes, have variously been called a "game-changer" (Ontario Premier Doug Ford) and "lesssafe" as the gold-standard PCR labtest(Quebec Health Minister Christian Dub, to Le Devoir).

The chair of McGill University's bioengineering department, Dr. David Juncker, leans to the Ford end of the spectrum provided the tests are used effectively. Right nowthey are not, he said, and it's to the detriment of the broader testing effort.

"The current testing system isn't very effective in terms of contact, trace and isolate it's too slow, it's too cumbersome, it has too many delays. That's one of the reasons we're failing in containing the spread of the pandemic," said Juncker, an expert on diagnostic testing.

The main area of concern for the provincial government also voiced by federal officials is thethe rapid test'slower accuracy, or sensitivity, and the risk of false negatives.

Questions about rapid tests answered by a biomedical engineer

4 years ago

Duration 3:51

David Juncker explains how the rapid antigen test, newly approved by Health Canada, can help detect the risk of active transmission.

Those fears are overblown, in Juncker's view, because the rapid testscan still help ferret out highly infectious people.

"If we just speak about diagnostic performance the PCR test is the most effective one," he said. "But if we think about what we want to use this for, as a public health tool that we want to use to contain and detect infectious individuals very quickly and isolate them very fast, that's where rapid tests can be very helpful."

An articlepublished in the journal Science Advance last month by researchersat the University of Colorado-Boulder and Harvardconcluded frequent, widespread testing with quick turnaround timeseven of asymptomatic peopleis the cheapest,mosteffective way of reversingsoaring coronavirus caseloads.

As the lead author of thepaper, Dr. Daniel Larremore, told CU Boulder Today, "it's better to have a less sensitive test with results today than a more sensitive one with results tomorrow."

Despite their limitations the currently approved rapid tests, which use the same nasal and throat swabs as the PCR test,are, in effect, a helpful yardstick for contagiousness.

"For adults with a high viral load, they have very good sensitivity we need to think about using their strengths, which means using them frequently," Juncker said.

That hasn't been happening, at least not in Quebec.

The provincial Health Ministry rolledoutrapid tests on a trial basis a few weeks ago in twolocations: the Saint-Eustache hospital and Maisonneuve-Rosemont hospital in Montreal. There are conditions, however, including double-checking the results with regular PCR test.

"There is still a recommendation by the federal [government]that we need to have both tests at the same time ...and this is not very clear by the general public," Quebec's health ministersaid.

The tests that are being sent to the Saguenay, called ID NOW and made by Abbott Laboratories, are a streamlined version of the PCR test. Quebec has about 77,000 of them.

The province also has1.2 million units of another Abbotttest called PANBIO, which uses a different technology known as an antigen testing. It's akin to a home pregnancy test.

Provincial health officials say they'll soon begin sending those kits to Quebec City, Montreal, Lvis, the Montrgie region, the Lower North Shore, Nunavik, the Magdalen Islands and Pierre Elliott Trudeau Airport, where they will be used to screen travellers bound for the north.

That represents progress,but Juncker says the main barrier to using them effectively comes down to a pair of federalrequirements: they must be administered by health professionals, and are only to be used on symptomatic patients.

"They're not being used in the kind of regime where they could have the biggest impact," he said.