At least 66 cases of Omicron subvariant detected in Canada
At least 66 cases of the Omicron subvariant BA.2 have been detected in Canada, “mainly from international travellers,” public health officials tell CityNews.
“The worrying part of it is that it’s increasing in prevalence in a background where other cases are decreasing,” Dr. Brad Wouters, Executive Vice-President, Science and Research at Toronto’s University Health Network says.
“And that means it has a selective advantage of some kind.”
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PHAC spokesperson Anne Génier says their scientists are working closely with national and international experts to monitor and evaluate BA.2 but adds it’s still too early to determine if it will become a variant of concern like the original BA.1 Omicron variant that quickly became dominant globally.
British Columbia is reporting 66 cases alone, as of January 21. The Public Health Agency of Canada says they are aware of 51 cases nationwide. It’s unclear how many of the B.C. numbers are captured in the national data.
“Where discrepancies exist between data reported by PHAC and data reported by provincial and territorial websites, data posted to provincial and territorial websites and dashboards should be considered definitive,” Génier wrote in an email.
“Differences may occur as a result of a short delay in reporting to PHAC or through ongoing data cleaning processes.”
She says that more information is required to determine if this sublineage will become a variant of concern.
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“BA.2 does exhibit some differences from BA.1, including some mutations that may affect transmissibility, detection and possibly immune escape,” Génier adds. “There is very limited evidence at present to determine how impactful the differences between BA.1 and BA.2 may be, hence the ongoing efforts by PHAC scientists to monitor cases here in Canada and track developments internationally.”
B.C.’s Ministry of Health says while the BA.1 and BA.2 variant form share many of the same mutations, “there are also mutations that are specific to each lineage.
A spokesperson with Public Health Ontario says the laboratory and surveillance team are analyzing this week’s data and plan to include further breakdown of Omicron sub-lineages in the Friday report.
Around 10,000 cases of BA.2 have been reported in at least 50 countries around the world. Some have dubbed it “stealth Omicron” due to it being harder to detect on PCR tests due to its genetic makeup. A handful of Omicron subvariants featuring different mutations have been identified so far — but BA.2 is getting attention because there is an increase in cases in Canada.
“As is done with all new variants, PHAC scientists along with national and international experts, are actively monitoring and evaluating this variant and the associated studies, for signs that it changes disease severity, spread, or impacts the effectiveness of diagnostic tests, vaccines or treatments for COVID-19,” Génier says.
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Scientists and health officials around the world are keeping their eyes on a descendant of the omicron variant that has been found in at least 40 countries. Photo courtesy: Viktor Forgacs
“It has a selective advantage of some kind”
Wouters says that the “stealth” version of Omicron is actually quite different than the initial form.
There are early signs BA.2 may be more transmissible than the original Omicron variant but it is not clear what impact it could have on the current wave of infections.
Since mid-November, more than three dozen countries have uploaded nearly 15,000 genetic sequences of BA.2 to GISAID, a global platform for sharing COVID-19 data. As of Tuesday morning, 96 of those sequenced cases came from the United States.
The BA.2 mutant appears much more common in Asia and Europe. In Denmark, it made up 45 per cent of all COVID-19 cases in mid-January, up from 20 per cent two weeks earlier, according to Statens Serum Institut, which falls under the Danish Ministry of Health.
“They’re actually quite different from each other,” Wouters says. “BA.2 has about 28 different mutations that are not present in BA.1.”
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An initial analysis by scientists in Denmark shows no differences in hospitalizations for BA.2 compared with the original Omicron. Scientists in that country are still looking into this version’s infectiousness and how well current vaccines work against it. It’s also unclear how well treatments will work in preventing serious illness.
The World Health Organization has called for research into BA.2 to be prioritized over other Omicron subvariants. Global health leaders could give it its own Greek letter name if it is deemed a globally significant “variant of concern.”
“It is growing. There’s no reason why Canada is going to be different than the U.K., Germany, Denmark and other places. It does have a selective advantage which is concerning,” Wouters said.
“I think it’s important for us to follow the emergence of variants and study them and be prepared for them. This is what our future looks like there are a lot of variants that would likely appear over time many of which won’t be very important and some of which will.”
With files from Mark McAllister and Laura Unger of The Associated Press
