As new COVID-19 subvariants move across Canada, experts say immediate testing can still be a good enough tool to detect the virus, even if it’s not the best all the time.
“These tiny, small adjustments in subvariants are very important in terms of the biological activity of the virus and its ability to evade our immune system, but immediate antigen tests are easily fooled,” said Colin Furness, an infection control epidemiologist and assistant professor at the University of Toronto’s faculty of information. he told Global News.
Rapid tests have a harder time detecting rapid spikes created through COVID-19 subvariants, but they have yet to identify the virus itself, Furness explained. However, there are things that must remain in the brain to get an accurate result.
When you do the test, there are a lot of problems because other variants of the virus produce other viral loads, Furness said.
“Now it’s quite difficult to get a positive result when symptoms start; you have to wait a few days,” Furness said.
“You can also have a negative check and still be infected, just because you’re not contagious or contagious enough to cause a positive check. “
Taking a sample not only from the nose but also from the throat is the way to check well and get an accurate result among the swirling subvariants, according to Furness.
The rapid tests run into a part of the virus called the nucleocapsid protein, according to Samantha Yammine, a science communicator in Ontario.
“While those new Omicron sublineages have some other mutations in this component of the virus, this is expected to render immediate antigen testing ineffective,” he told Global News.
“But possibly it would take more than one check to detect it, or possibly it would advance its symptoms to be detected. “
In assessing the effect of Omicron sublineages, such as the highly transmissible BF. 7 that is recently spreading through China, where the virus was first detected, Public Health Ontario expects there to be limited effect on immediate testing in the province. .
“I don’t think we have evidence to recommend that the immediate antigen tests we have are no longer useful,” Yammine said.
“I think they are useful in helping us get through this phase of the pandemic when used correctly. “
While limited to immediate testing and regarding COVID-19 variants, what has been done suggests that they still work.
While a study published in April in the Journal of Clinical Microbiology found that the sensitivity of an immediate test can be changed with other variants, most infectious cases are still detected.
According to a study on the accuracy of immediate testing in the original variant of Omicron, published in September in The BMJ, a peer-reviewed medical journal, only one in three tests analyzed showed statistically significant minimal sensitivity.
The tests, known as Clinitest, are through Health Canada to be manufactured in the country.
“Studies show that there is a relief in sensitivity, but they have concluded that the remaining limit of chopped onion is sufficient to trip over those variants,” Dasantila Golemi-Kotra, an associate professor in the faculty of science at the University of York, told Global News.
With instances peaking last December, immediate testing began to be distributed across the country. While some Canadians were unwilling to get their hands on one kit at the time, others had to inventory several.
While the first symptoms of a resurgence of the virus this fall and winter, Golemi-Kotra doesn’t think Canada will again be in a hurry for immediate testing.
“I don’t think we’re going to see a scenario we were in a year ago,” he said.
But according to Don Sin, a pulmonologist at St. Paul’s Hospital in Vancouver and a professor of medicine at the University of British Columbia, it’s best to be prepared.
“I think it’s much better to be ready than to be taken at a numerical disadvantage,” he told Global News, noting that lately Canada has a falsified inventory of immediate tests.
Earlier this week, Theresa Tam, Canada’s leading director of public fitness, said she was preparing for the “worst-case scenario” related to COVID-19 variants.
Earlier this month, Health Canada gave the green light to the Pfizer-BioNTech booster targeting the original variant of Omicron and its BA. 4 and BA. 5 strains. Moderna’s updated booster was also approved in Canada five weeks ago.
Health Canada knew that, as of mid-September, 88 per cent of detected COVID-19 cases were BA. 5 and 9 per cent were BA. 4.
As of Oct. 15, there were 21,188 cases of COVID-19 in the country, and Ontario had a number of 9689, according to government data.
According to the World Health Organization on Wednesday, the virus remains a worrisome public health emergency.
–Con from The Canadian Press