More than a week after Manitoba’s top doctor acknowledged the possible presence of the India variant in the province, nothing more has been said about it.
On April 26, chief provincial public health officer Dr. Brent Roussin told a news conference about an unconfirmed positive result for B.1.617, the same strain of COVID-19 that is causing widespread deaths in India. He said public-health officials had "early indications" in late April that a positive case of COVID-19 linked to international travel may have been caused by B.1.617. As of Thursday, that was still not confirmed, and a provincial spokesperson had no additional information.
That particular strain of the virus has not been classified as a variant of concern. It is considered a variant of interest in Canada, and is not subject to the same kind of mandatory surveillance that is in place for the three variants of concern (the U.K., South Africa and Brazil strains), although Roussin has said Manitoba is treating all variant cases as if they are variants of concern.
As the virus evolves faster than Canadians can be vaccinated, identifying and tracking new and potentially dangerous mutations is particularly important. Specific screening tests to detect emerging variants do not exist. New variants can only be detected via genetic sequencing, and over the past year, most of that work was being done in Winnipeg at the National Microbiology Lab.
Now, provinces are increasingly doing their own sequencing, and more than a dozen labs across the country do that work. Between five and seven per cent of Canada’s positive COVID-19 test results are sequenced to look for emerging variants, said Dr. Catalina Lopez-Correa, executive director of the Canadian COVID Genomics Network.
The U.K., considered a world leader in sequencing, does eight per cent. The focus has been on sequencing positive COVID-19 samples from international travellers, but as more people are vaccinated, Canadian labs are looking more closely at samples from people who’ve been reinfected with COVID-19 after being vaccinated.
To keep track of quickly emerging variants, and understand which ones to watch out for, Canada and other countries have been categorizing COVID-19 strains as variants of interest or variants of concern.
There are 10 variants of interest in Canada, including the India variant. All of those 10 variants have genetic mutations that indicate at least one of these traits: they’re more contagious, they cause more severe illness or more illness among age groups that previously haven’t become seriously ill, they’re more difficult to detect or they’re resistant to vaccines. Variants of interest won’t be upgraded to the variant of concern label until further studies offer more proof.
It’s unlikely screening tests, which are faster than genetic sequencing, will be developed for variants of interest.
It takes at least three weeks for a lab to develop a new PCR screening test, a senior Manitoba health official told the Free Press during a recent technical briefing. By that time, the landscape may have changed considering how quickly the virus evolves. It’s not considered practical to design a new screening test for each variant of interest.
Katie May reports on courts, crime and justice for the Free Press.
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