As tensions rise in Canada over vaccine supply problems, experts advising the federal government say we’re falling woefully short in another area that could make a huge difference in controlling the COVID-19 pandemic: rapid testing.
And unlike the vaccine issues, we have only ourselves to blame for the lack of rapid testing. The tests are here and they’ve been available for months.
Rapid tests do not replace lab-based testing, but they’re faster, cheaper and easier to use. They miss some positive cases, but focusing on that misses the point. Their usefulness comes through repeated, consistent use on Canadians who would otherwise not be tested. Frequency and speed makes up for lower accuracy.
For the time being, there is no supply shortage of rapid tests. In fact, there’s a glut. In B.C., longterm care organizations are fuming at provincial health officials for letting a million rapid tests procured by the federal government sit unused in warehouses, where they’ll soon expire. As of last week, Quebec had administered just 18,000 of the 2.6 million rapid tests it’s been sent.
The main obstacle to deploying rapid tests is the stance of some health officials who claim the tests are cumbersome and inaccurate — to the intense frustration of experts who argue a very valuable tool is being neglected. When the federal government’s COVID-19 Testing and Screening Expert Advisory Panel released its first report last month , increasing rapid testing was a priority recommendation.
“There’s deep concern among especially medical professionals and public health professionals about what will happen if we don’t use this as a tool in our overall strategy in the coming few months,” said Sue Paish, co-chair of the advisory panel. “That’s why we chose that topic as the first that we would address as a panel. There’s an opportunity to get ahead of this, but that opportunity is rapidly evaporating.”
Dr. David Naylor, who sits on the advisory panel and co-chairs the federal COVID-19 Immunity Task Force, said the case for widely adopting rapid testing has been clear for months. Although he wishes the tests had been approved sooner, he said provincial governments have had ample time since their approval in the fall to implement them and could have used them to mitigate the second wave.
“Instead, in what has become a maddening pattern, somehow the rollout got bogged down,” said Naylor, a former dean of medicine and president at the University of Toronto, in an email. “Now here we are, with millions of tests unused, and a perilous three or four months ahead as more infectious variants spread and Canada tries to get on with wider immunization coverage. I simply can’t imagine how this critical transitional period can be managed without a massive expansion of rapid screening tests.”
The National Post spoke to a range of experts to learn how a rapid testing campaign could be implemented if the desire was there to do so. The program could reduce the number of outbreaks as we wait for vaccinations, and make it much easier for schools and workplaces to stay open even if a third wave comes. Above all, the program would save lives.
Here’s how to do it.
Rapid tests are for screening
Nobody who advocates rapid testing thinks it’s a replacement for lab-based polymerase chain reaction (PCR) testing. When critics discuss it on those terms, they are setting up a straw-man argument.
Rapid tests are a screening mechanism. They can be used to quickly find COVID-19 in people who would otherwise not be tested. A positive rapid test means the person can be immediately isolated until the case is confirmed with a PCR test.
It is mind boggling that we are not using all the tools in our toolkit
There are different kinds of rapid tests, but this story refers to antigen tests, which require little specialized equipment and work by detecting proteins on the surface of the virus. Estimates vary, but antigen tests are typically in the range of 75 per cent to 98 per cent sensitive compared to PCR. But while PCR tests are so sensitive they detect even trace amounts of virus in people who are no longer infectious, antigen tests will catch almost everyone who is carrying a high viral load — in other words, people who are the most infectious and the highest priority for getting into isolation.
The key to rapid testing is to do it repeatedly — at least once a week, but ideally twice a week. Someone who tests negative one day could become infectious a day or two later. Even so, experts say any level of rapid testing is better than none.
“There’s nothing magic about twice a week,” said Dr. Irfan Dhalla, the other co-chair of the advisory panel and vice-president at Unity Health Toronto. “If you have the resources to do it five days a week, do it five days a week. If you don’t have the resources to do it twice a week, well, once a week is a lot better than zero times a week. And once every two weeks would be better than never.”
How the test works
The most widely available rapid test in Canada is the Abbott Panbio test. Compared to PCR testing, it is very simple to use.
First, you swab the test subject with a nasopharyngeal swab, the kind that goes deep into the back of the nose. This is the only difficult part of the procedure. (Health Canada is expected to eventually allow the throat-and-nose swab for Panbio tests, which would make it significantly easier.)
Once the swab is done, you place it into a small tube and swirl it with fluid. Then you squeeze the tube into the bottom, which functions as a dropper. You put five drops of the fluid into a little well on a test device, and wait 15 minutes while the fluid leeches into the device and changes colour.
At this point it’s basically a home pregnancy test. Two lines is a positive result. One line is a negative result. No line or a line in the wrong spot means the test didn’t work properly. That’s it.
In Nova Scotia — the province that embraced rapid testing the earliest — public health officials have been training volunteers without medical backgrounds to run the Panbio test.
“We trained them very quickly,” said Dr. Lisa Barrett, the driving force behind Nova Scotia’s pop-up rapid testing centres. She said it takes them about 45 minutes to initially train a group. Some volunteers do the screening questions, some read the results and send out text messages. For those administering the tests, they have to perform the swab 10 times correctly to be deemed ready.
“Some (volunteers) were university students who had nothing to do,” Barrett said. “Some were people in the community who just wanted to contribute. Some were retired librarians, never stepped foot in a hospital in their lives. We taught them all how to use personal protective equipment, so the gowns, gloves, masks and shields. How to properly put it on and take it off.”
Barrett, an infectious disease physician at Dalhousie University and the Nova Scotia Health Authority, said there’s no reason medical staff are needed to administer the Panbio test on adults; anyone can be trained to do nasal swabs safely.
Jurisdictions make their own policy choices on this, but even if a nurse does the swab, non-medical staff can do everything else. Barrett said the main thing is to shed the attitude that the perfect is the enemy of the good. She said Nova Scotia’s program isn’t any great leap of creativity.
“This is just saying, what can we do? Can we build a framework around (testing) that still provides safety to people?” said Barrett. “And let’s not forget, people invade their own personal orifices much more dangerously than this particular swab. Trust me.”
Where to do the screening
An obvious place for rapid test screening is for staff in long-term care homes, where the pandemic has been brutally deadly.
Simon Fraser University professor Caroline Colijn, who holds the Canada 150 research chair in mathematics for evolution, infection and public health, co-authored a study concluding that if care home staff were screened every three days with a Panbio rapid test, it would reduce outbreaks by 45 to 55 per cent compared to no regular screening. Even doing it once a week would reduce outbreaks by 25 to 40 per cent.
Again, rapid testing would not replace PCR testing in a high-risk setting such as this. It would supplement it.
But in B.C., provincial health officer Bonnie Henry has been a consistent skeptic of rapid tests, saying they aren’t accurate and wrongly claiming it takes three people to administer one rapid test.
Colijn said she’s baffled by the resistance.
“It is mind boggling that we are not using all the tools in our toolkit, we’re only using our favourite ones that we started with,” Colijn said. She thinks it’s in part because public health officials are exhausted and stretched beyond their capacity. But if it’s simply a matter of resources, she said that’s on governments to find a way to make it happen.
“We still have to get the country out of a pandemic,” Colijn said.
Dhalla said there are two other settings where we should be ramping up rapid test screening: large workplaces and schools.
“My first preference would be to get these tests into settings where people either have to congregate or where we really want people to congregate,” he said.
Large workplaces are finally starting to roll out rapid test screening, with Air Canada, Loblaws, Suncor and other major corporations announcing programs. Ontario announced it will send out 300,000 rapid tests per week to key business sectors such as manufacturing and food processing. In contrast to some provinces, Ontario has now ordered an extra nine million Panbio tests for distribution, the health ministry says.
Schools are a trickier matter, at least until Health Canada approves a gentler swab for rapid testing — or, even better, a rapid test that only needs saliva to work. Dhalla said he thinks it’s probably impossible to have healthcare professionals do the nasopharyngeal swab on young children twice a week. In the meantime, though, a regular rapid test for teachers would be an achievable goal.
Dhalla said different regions should decide what works best for them. But if the virus is known to be circulating, he said, find a way to get the tests done. One test is better than no test.
The longer health officials wait on this, the more difficult it will be. Regular screening requires a steady flow of tests. For now, at least, it appears doable. The federal government has shipped out 13.5 million Panbio tests to provinces, and more are coming.
“There doesn’t appear to be a supply issue in respect of the test at this time globally,” said Paish, CEO of the Digital Technology Supercluster. But she said that could change quickly as vaccines are delayed and countries look to other strategies. “We have a moment to aggressively procure as a country for the entire population a sufficient amount of rapid tests,” she said.
Naylor said he senses a lot of “epidemic fatigue and frustration” among the Canadian public, who he believes has largely done a good job of following the COVID-19 guidelines to the best of their ability.
“If rapid tests are positioned correctly, they could not only help the overall epidemic response in meaningful ways, but also give countless Canadians a sense of participating more actively in what we all hope will be the last phase of this public health crisis,” he said. “I think the public needs and deserves that opportunity.”
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