As the number of confirmed COVID cases caused by the new XBB.1.5. subvariant continues to rise in Canada, adopting a better approach towards testing and wastewater surveillance could help detect early signs of new strains, according to some epidemiologists.
“To think that we are living in Canada … and yet if you’re sick, you cannot get tested for COVID easily — I think that is just the antithesis of medicine,” Dr. Donald Vinh, a medical microbiologist at the McGill University Health Center in Montreal told Global News.
“We don’t know exactly how much reinfection XXB.1.5. can cause … But if the previous waves have ever been a lesson to us, it’s not to take variants lightly,” Vinh said.
“Every wave that we’ve had has led to an increase in hospitalizations. And even though we can buffer that increase, that’s come at a price to our health-care system. And so … going forward, we should be very aggressive against XXB.1.5. or whatever other variant is emerging,” he added.
The Public Health Agency of Canada (PHAC) told Global News on Wednesday that it is aware of 21 detections of the XBB.1.5. variant in Canada, but added that proportions and growth rates would not be reported until there is sufficient data.
XBB.1.5., which is a subvariant of Omicron, has been detected in 29 countries to date, according to the World Health Organization (WHO).
PHAC did not identify whether it considers this mutation to be a variant of concern, noting a number of complex factors that play into such a decision, including whether scientists and public health officials observe an actual change in the behaviour of the virus.
Making testing more available
Vinh says that at the moment he’s “perplexed” by Canada’s COVID-19 testing strategy.
“One could argue that PCR testing on a mass scale is overwhelming our laboratory diagnostic capacity. And I don’t deny that as a microbiologist. That is absolutely true. But we need to come up with alternative strategies rather than just restricting testing,” he added.
Vinh also argues that it’s not known how well rapid tests perform against emerging variants like XXB.1.5. and that’s why Canada needs “to reopen testing to people who are symptomatic.”
“I think that by making diagnostic tests available to people who are sick and seeking the tests, we’ll have a better understanding not only for their individual care but for public health perspectives as well,” he said.
As of now PCR testing is more targeted and used toward people who are visiting emergency rooms or physician offices, Corey Neudorf, University of Saskatoon epidemiologist, told Global News.
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This means that not everyone with symptoms gets a detailed test like a PCR, but there can still be enough people getting tested for public health officials to keep track of cases, Neudorf said.
“You can keep a watch on what type of virus is making up the majority of COVID and monitor for these very various types of variants,” Neudorf added.
Meanwhile, Canada has announced a new requirement for travellers from China, Hong Kong and Macau.
There has been an explosion of COVID-19 illness after the Chinese government lifted harsh restrictions. In a news release issued on Dec. 31, PHAC said that China has not provided enough “epidemiological and viral genomic sequence data” on those cases.
That includes information about what variants are circulating and any potential new ones emerging.
Starting Thursday, Canada is requiring travellers from these regions to provide proof of a negative COVID-19 test before boarding flights to Canada. The test must be taken no more than two days before departure.
Utilizing wastewater surveillance
Vinh says the infrastructure for the wastewater surveillance system while existent in Canada, needs resources to remain operational.
“The wastewater surveillance program actually allows not just the monitoring of COVID, but in fact, it has the potential to monitor or survey a wide range of infections … wastewater surveillance strategy is an excellent one that has been grossly underutilized,” Vinh said.
He says that data generated from wastewater needs to be rapidly analyzed and made available so that public health can prepare itself if necessary for whatever is detected.
However, Gerald Evans, an infectious disease expert at Queen’s University, says not every location in Canada has the technology for wastewater detection.
“For instance … we have good wastewater testing in the city of Kingston, but in other centers, that doesn’t exist … Wastewater, though, can be really effective,” said Evans.
He explains testing wastewater for variants can be a bit tricky because there’s much viral RNA — a macromolecule that functions to convert the genetic information of DNA into proteins — in wastewater detection that needs to be separated and looked at.
“To look for and survey for these different variants or sub-variants is a little bit more challenging than taking a single isolate that you would get from a patient, for instance, which is a bit cleaner and you’re able to do your sequencing a lot faster and with a lot more accuracy,” said Evans.
However, he says testing wastewater is still useful because it’s a method of finding variants before they actually cause infections in people.
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“Wastewater is useful but it needs a lot of resources, including financial means, that are required to do that effectively,” Evans said.
“XXB.1.5 is telling us that we’ve got a little ways to go yet to get ourselves out of the pandemic. We’re still seeing now the emergence of variants and all of this sequencing data, whether it’s from specimens we get from patients or from wastewater, is still really important during this pandemic,” he added.
“People want to get out of the pandemic. I certainly do as much as anyone else. But one of those ways is we have to invest in the ability to use scientific methodology to help us figure that pathway out.”
What is being done?
Canadian scientists are now stepping up airplane wastewater testing to try to get an early warning of potential new variants.
The method will be used at Vancouver International Airport and Toronto’s Pearson International Airport starting Friday.
Samples of fecal matter that come from airplane toilets will be taken to help scientists identify what coronavirus variants and subvariants passengers and crew might be bringing into Canada.
“A sentinel system for new variants — that’s really where we see the value add of airport testing,” Dr. Guillaume Poliquin, vice-president of the Public Health Agency of Canada’s National Microbiology Laboratory, told The Canadian Press.
“The airports really represent a large proportion of people – many of whom are international travellers coming into the country,” said Lawrence Goodridge, a University of Guelph professor who is one of the researchers.
“The variants that are major public health concerns thus far have all originated outside of Canada. So it’s a great way to understand what’s coming in and that data then can be used to make public health decisions.”
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Goodridge, from the Pearson Airport wastewater testing project, specializes in food microbiology and used wastewater surveillance to detect food-borne diseases before the COVID-19 pandemic.
Historically, it was also used to detect polio, he said.
Wastewater testing in airports and airplanes has proven invaluable, Goodridge said.
“I would like to see this expanded to (other) major international airports in Canada,” he said. “We’re seeing what’s coming into the country, you know, in real time.”
– with files from The Canadian Press and Global News’ Teresa Wright and Kyle Benning
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