Some new Omicron subvariants — sparking concern due to their growth advantage and signs of immune evasion — have been identified in Alberta, and they're on track to drive the province's next COVID-19 wave, according to a modelling expert.
The global GISAID database shows more than 60 cases within the BQ family of variants — which are offshoots of BA.5 — have been identified through genetic sequencing in Alberta.
This data is delayed by several weeks, though, because the sequencing conducted by the provincial lab takes time to complete.
"That's going to be our next wave," said Sally Otto, a B.C-based evolutionary biologist.
According to Otto, there is an "alphabet soup" of Omicron subvariants around the world with similar mutations that allow the SARS-CoV-2 virus to get around the immune system and infect cells.
But variants within the BQ family — including BQ.1 and BQ.1.1 — are her key concern at the moment because they have a lot of these mutations and they evolved out of BA.5, which was already more transmissible.
"So now it's an easily transmitted variant that's a little more immune evasive," said Otto, who teaches at the University of British Columbia and is a member of an independent B.C. COVID-19 modelling group.
BQ set to take over by December
According to Otto, BQ variants are spreading the most quickly in Canada, and she estimates they now account for 20 per cent of Alberta's COVID-19 cases.
"If it's doubling every week or two, it won't be that many more weeks before it's half of the viruses that we're seeing in Alberta," she said.
"So in November we would expect it to become 50 per cent or more of the viruses from Alberta."
The World Health Organization recently noted BQ.1 warrants close monitoring due to a possible higher reinfection risk and growth advantage.
It said there is no evidence it causes more severe disease, adding "protection by vaccines … against infection may be reduced, but no major impact on protection against severe disease is foreseen."
While the trajectory of the variants is difficult to predict, Otto is not expecting cases to explode the way they did during previous waves.
"BQ has been at a higher frequency in Europe and we're already seeing case numbers and hospitalization rates turn around there," she said.
"I don't think we're going to see a vast number of individuals infected with BQ. More than what we've got now. More than what we had with BA.5. But not everybody."
Vaccines and masks
This cycle of fresh variants replacing old ones and driving new waves is to be expected as Omicron continues to mutate, according to Dr. Daniel Gregson, a Calgary-based infectious disease physician.
"You see new variants episodically, and why some variants spread in some districts versus others is sometimes unknown," said Gregson, an associate professor at the University of Calgary's Cumming School of Medicine.
"What happens over time generally is this switch from one variant to the next.… So we're likely to see our BA.5 wave disappear followed by another wave."
Gregson is encouraging Albertans to get vaccinated, including booster doses, and to watch wastewater data for transmission trends.
"The best you can do is keep your immunizations up to date. If you're higher risk, cut back on your number of contacts, use masks when you're in crowded places."
This will help reduce the surge in influenza cases, which is expected soon, too, he said.
While Alberta Premier Danielle Smith has repeatedly signalled her opposition to public health measures, Gregson said revisiting masking rules may be necessary from a public health perspective if transmission rises significantly.
"Masking on public transit, masking in public venues might be a way to sort of cut back on the total burden of disease in the community."
Meanwhile, an Alberta Health Services spokesperson said the provincial lab has been actively monitoring for SARS-CoV-2 variants since the beginning of the pandemic.
It's working on a way to speed up the identification of these latest variants.
"[Alberta Precision Laboratories] performs variant screening as well as sequencing to identify variants of concern and specific lineages. While the variant screening provides a quick result based on detecting a few key mutations in each variant, sequencing requires more time and provides a fuller picture of the virus genome," spokesperson Kerry Williamson said in a statement shared with CBC News.
"Currently, sequencing is how Alberta identifies newly emerging Omicron lineages … though variant screening tests are being designed to detect them more quickly."
Williamson noted XBB — a recombinant variant also identified as one to watch by the World Health Organization — is being monitored by the provincial lab.
Three cases of have been sequenced in Alberta, according to the GISAID database. But Otto said that particular variant does not appear to be growing as quickly in Canada.