Where are Canada’s rapid at-home coronavirus tests?
Infectious disease experts have been asking themselves — and public health officials — this for months.
“If every Canadian had that in their medicine cabinet, we might be able to test our way out of this,” said Colin Furness, an infection control epidemiologist and assistant professor at the University of Toronto.
“The stakes are high. We really do need it now.”
But like any medical test, there are hurdles to cross before getting a stamp of approval. Experts believe the benefits would be significant and that those benefits are underscored by Canada’s coronavirus resurgence.
Swabbing at home
On this specific front, the United States is one step ahead of Canada.
On Tuesday, the Federal Drug Administration (FDA) authorized its first rapid test that can be performed entirely at home and deliver results in 30 minutes.
The single-use test kit, from California-based Lucira Health, allows users to swab themselves to collect a nasal sample. The sample is then swirled in a vial of laboratory solution that plugs into a portable device. Results are displayed as lights labeled positive or negative.
According to company-run trials, Lucira’s coronavirus tests were able to accurately detect 94.1 per cent of infections, as well as 98 per cent of healthy, uninfected people.
The test currently requires a prescription, which will likely limit its initial use, but Furness is hopeful for a wider approval. He said at-home tests have the ability to not only assist busy public health agencies but also help keep businesses and schools afloat.
“We have to think of it like a screening tool, a magic thermometer,” he said. “It doesn’t provide you a diagnosis but it tells you something’s wrong.”
Health Canada has approved more than three dozen different tests for COVID-19. Only six of them are “point of care” or so-called rapid tests.
None of them are at-home or self-testing kits.
Many of these tests have gotten a “bad rap” because they’re considered less sensitive than lab-based tests, said Dr. Prabhat Jha, an epidemiologist at the University of Toronto, and director of the Centre for Global Health Research at St. Michael’s Hospital.
[ Sign up for our Health IQ newsletter for the latest coronavirus updates ]
The “gold-standard” COVID-19 tests (PCR tests) need to be processed in a lab and usually take at least a day to provide results. Rapid tests can be processed on-site — sometimes in just a few minutes — but are generally less reliable.
Health Canada requires rapid tests to meet a minimum standard of 80 per cent sensitivity or accuracy before their application can be approved.
Jha believes there’s too much weight being put on this threshold. He believes an effective home testing strategy is a critical part of Canada’s response to the second wave of the virus.
“Making them available to nursing home staff, for example, would be worth it. Sure, there’d be some you miss, but you could substantially reduce the number of people who are showing up positive at a nursing home, asymptomatically,” he said.
“We don’t have to let the perfect be the enemy of the possible.”
Health Canada says it has not yet received any applications for at-home tests to be approved in Canada.
However, Federal Minister Patty Hajdu confirmed Wednesday that Health Canada has reached out to Lucira Health and ask them to submit their test-kit for evaluation. The agency later told Global News in an email that it has “proactively contacted numerous manufacturers” of at-home tests in the U.S. to have them apply to the Canadian market.
“The whole world is looking for tools that can help us on the screening side and on the testing side,” said Hajdu. “As soon as there’s a rapid test with a certain degree of sensitivity and accuracy, of course, the regulators will approve that test. At the end of the day, you can’t rush science.”
Furness isn’t of the belief the science is slow in this case. He says there are unique hurdles self-testing devices face, the first being the testers themselves.
The big problem with at-home tests is whether people without any medical training can accurately screen themselves and interpret the results, he said.
Home pregnancy tests, for example, were subject to years of scrutiny before the FDA and others approved their use in the 1970s.
Clinical studies by Lucira Health show 100 per cent of users aged 14 and older were able to run the single-use test kit properly.
Furness is skeptical of those results.
“People aren’t necessarily as good at creating a sample out of their own heads,” he said.
“The effectiveness of the test is going to be very heavily dependent on the competence of the person drawing the sample.”
Gaps in testing
Past rhetoric from Canada’s top doctors might also be to blame for the lack of at-home test candidates in Canada, Furness said.
He suggested the federal government “sent the wrong signals” to technology and innovation communities when rapid tests first came into the pandemic-psyche.
Throughout the summer, Dr. Theresa Tam and Prime Minister Justin Trudeau pushed back on pressure to approve rapid tests, despite versions of the antigen test being used in Japan, Britain, the U.S. and parts of the European Union at the time.
They later walked back their stance, acknowledging they wanted to see more concrete data on the methods. But “we don’t really know what damage they did by being so adamant,” said Furness.
Tam said Friday that Canada has mobilized more than 3.8 million rapid tests in recent weeks, but noted that more can be done. She suggested at-home tests, specifically, should be taken with caution.
“We welcome the submissions, but we haven’t yet received one and got satisfactory information from the manufacturers, or we need to test in clinical terms,” said Tam.
“A negative test under any of those circumstances doesn’t necessarily mean you don’t have the virus. So some of these tests might need serial testing. Those are the parameters we’re going to have to look at.”
Furness put it plainly: “Health Canada’s got their priorities wrong.”
He said Canada’s “biggest blind spot” right now is asymptomatic transmission. With broad testing being withheld in Ontario and backlogs being reported at testing centres in much of the country, “even a low sensitivity test would still be enormously useful,” he said.
“If we could take the proportion of asymptomatic transmission and cut it in half, we would really put a dent in transmission,” said Furness.
“Given the sh-t show we’re in, we don’t need high sensitivity to move the needle.”
He used Ontario schools as an example. The province currently requires only those showing COVID-19 symptoms or a confirmed contact with someone who tested positive to get tested. That test is a definitive diagnostic test, a PCR.
“That’s all Ontario has right now. There’s a huge gap,” he said. “There’s the teacher before they go to work. The kid before they go to school. The parent at drop-off.”
“We could be and should be putting this test into everyone’s hands, constantly screening themselves. We need to do better than, ‘Hey does your kid have a fever and a cough?’ because that’s a really weak way to do screening right now.”
–With files from the Associated Press and Global News’ David Akin
Source: Read Full Article