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Canada is entering a period of relative calm as the Omicron-led fifth wave subsides across much of the country. But our ability to track new and existing variants is at risk as access to testing remains severely restricted – leaving us vulnerable to epidemic infection.
Dr Theresa Tam, Canada’s chief public health official, said Friday that COVID-19 levels have continued to decline in much of Canada, with the weekly number of cases down 26 per cent, and hospital and intensive care unit admissions down 20 per cent. compared to the previous week.
“However, since the virus continues to spread widely, some jurisdictions are reporting weekly increases in the number of cases, and others may see additional bumps in the coming weeks,” she said.
“At the same time, there is an ongoing large volume of PCR tests being performed and ongoing genetic sequencing of circulating virus variants.”
But the level of COVID-19 testing in Canada has already been achieved significantly decreased Since the beginning of the Omicron wave – with over 100,000 tests conducted daily in early Decemberabout 150,000 inches early januaryto just over 50,000 as of Friday.
This makes it nearly impossible to get a clear idea of the true number of COVID-19 cases in Canada, and severely limits the number of test samples that can undergo genetic sequencing to detect the presence of variants.
The world cannot give up testing amid the threat of variables
WHO coronavirus expert Maria Van Kerkhove said this week that while there was a 20 per cent drop in COVID-19 levels globally in the past week compared to the previous week, the drop “may not be real” due to a lack of testing.
“We are very concerned about the decline in testing around the world,” she said on Tuesday.
“We need to be smart about this, we need to be strategic about this, but we can’t give it up – and what we don’t want to see is dismantling these surveillance systems that have been put in place for the COVID-19 virus.”
Van Kerkhove said widespread COVID-19 testing is “critical” for discovering new variants and understanding how the virus evolves, because you can’t sequence test samples for the presence of variants if people haven’t already been tested.
She added that the virus will evolve over time because the more it spreads, the greater the chances of it changing – but while more variants can present with “worrisome” characteristics, they will not become a public health threat unless they spread.
“The only thing I’m sure of is that there will be a new species,” said Angela Rasmussen, a virologist with the Vaccines and Infectious Diseases Organization (VIDO) at the University of Saskatchewan.
“With three billion vaccinators worldwide, along with convenient precautions aimed at reducing transmission, I feel very confident in saying that the next alternative is not a question of if, but when.”
Rasmussen said that while it’s very difficult to say exactly what the next variant will look like, the emergence of Omicron should make us pause as it “surprised us” due to its “uncertain origins”.
“Unlike alpha, beta, gamma, and delta, the omicron did not originate from widespread transmission in the unvaccinated populations,” she said.
“I’m very concerned about another variable coming out of nowhere — coming out of an unexpected source, like a patient with a persistent infection or from a spill to animals.”
Canada needs ‘advance warning systems’ for variables
If PCR testing isn’t widespread in Canada anytime soon, or at all, experts say we need to build other COVID-19 surveillance systems.
David Naylor, who led the federal investigation into Canada’s response to the 2003 SARS epidemic and now co-chairs the federal government’s COVID-19 Immunity war unit, said Dr.
“As Omicron has shown, it is difficult to predict the effectiveness of vaccines and past infections in preventing spread and, most importantly, avoiding dangerous diseases. That’s why we need advance warning systems.”
Naylor said there are two main advance warning systems to build now that access to testing has been significantly restricted — strengthening national wastewater monitoring and creating a national PCR testing program using random samples of tests to track the virus.
Some Canadians are struggling to book PCR tests or find rapid antigen tests, and experts say testing challenges may affect the accuracy of daily COVID-19 case counts. 3:34
Marc-Andre Langlois, a molecular virologist at the University of Ottawa who heads the Coronavirus Variants Rapid Response Network (CoVaRR-Net), says wastewater monitoring is one of the last reliable ways to track and sequence variants with downsizing testing.
“Where do we capture the variables? Where can we systematically monitor this? Well, everyone goes to the toilet, right?” He said.
“If we catch what’s going on in our wastewater, for one thing, we’re overcoming all the privacy issues, because it’s a mixture of the population, and second, we now have better technologies than just PCR.”
Scientists now have the ability to sequence variants directly from wastewater samples, Langlois said, allowing them to better determine the prevalence of a particular variant in a given population as well as the general level of virus in the community than the PCR test.
Wastewater monitoring is also a more cost-effective method, allowing researchers to test thousands of samples simultaneously — compared to the astronomical cost of managing, treating and sequencing Over 58 million tests have been conducted in Canada so far.
said Eric Artes, Canada Research Chair in Virus Control and Professor of Microbiology and Immunology at Western University.
“If you think about it, you can add $150 for every test we run across the country and report on an individual case — it’s an incredible cost.”
With testing systems maxed out across the country, some experts are turning to wastewater testing as a way to determine how much COVID-19 is already in our communities. 2:04
Art says he fully believes in individual testing when someone has to be hospitalized with severe COVID-19 and needs confirmed results in order to access treatment, but it “doesn’t make sense” for those without serious symptoms and recovering back home.
“It’s not perfect,” he said. “But I would say it’s more accurate in the long run than individual testing because not everyone will be tested.”
Canada lacks a national wastewater testing strategy, and much of the data is not publicly available across the country, something Langlois and Arts said should be invested in and standardized across the country.
Langlois said that if national wastewater monitoring data is publicly available across the country, Canadians can use it to make individual decisions to protect themselves if their community experiences a sudden increase in COVID-19 or the emergence of a future variable.
“There has to be some kind of dashboard telling residents ‘OK, the infection rate is going up, I’m about to get a booster dose, maybe this is the time for me to get a booster,'” he said.
“With additional government funding, it could develop into its own entity where there is public wastewater monitoring for other common pathogens – such as influenza.”
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