New immune-evasive Omicron strains are coming. Is Canada prepared?

That is an excerpt from Second Opinion, a weekly evaluation of well being and medical science information. If you have not subscribed but, you are able to do that by clicking right here.


  • New Omicron subvariants that may evade immunity higher than earlier strains are being detected in additional nations world wide — together with Canada.

  • These subvariants are rising at a time when Canada’s health-care system is already beneath pressure as flu season is quick approaching. 

  • Up to date COVID-19 vaccines are our greatest line of defence — however uptake is lagging. 


Canada is heading right into a doubtlessly brutal winter as COVID-19 hospitalizations rise, Omicron continues to quickly mutate and booster uptake stays stagnant — all at a time when flu season is returning and the health-care system is already beneath intense strain.

COVID-related hospitalizations are at the moment increased than any earlier fall within the pandemic, almost double final October and nearly 4 occasions greater than in 2020. 

And new Omicron subvariants which have been proven to higher evade immunity and doubtlessly drive new COVID waves are gaining floor, with greater than 300 Omicron subvariants being tracked by the World Well being Group worldwide.​​

“All the subvariants of Omicron are displaying elevated transmissibility and properties of immune escape,” the WHO’s COVID-19 technical lead Dr. Maria Van Kerkhove stated throughout a information convention Thursday, including that subvariants XBB and BQ.1.1 have proven “important immune evasion.”

“That is of concern for us as a result of we have to be certain that the vaccines that are in use worldwide stay efficient at stopping extreme illness and loss of life,” she stated. 

“We do not see a change in severity [with XBB and BQ.1.1], nevertheless it’s very early and we have now very restricted information to truly assess this.” 

A few of these subvariants are already being detected in nations like Singapore, India, Denmark, Australia, Indonesia, the U.S. and Canada — with BQ.1.1, BQ.1, BA.2.75.2 and XBB collectively making up greater than 10 per cent of latest virus samples sequenced globally.

These Omicron subvariants have key mutations on their spike proteins that permit them to extra simply evade the primary line of defence for our immune system and enter our cells, permitting them to get round immunity from vaccination and prior an infection.

“It is like a complete bunch of horses within the race in the mean time they usually’ve every gathered these completely different mutations,” stated Sally Otto, a College of British Columbia evolutionary biologist and virus modelling professional on the Coronavirus Variants Fast Response Community.

“Meaning it is enjoying a special sport, it is evolving in several methods and that’s to masquerade from our immune system.”

Canada making ready for ‘worst case situation’

Whether or not or not a number of of those Omicron subvariants will drive one other wave in Canada or globally stays to be seen, however the pace with which they’re being detected in different nations is trigger for rising concern amongst consultants monitoring the virus.

Eric Arts, a Canada Analysis Chair in Viral Management and an immunology professor at Western College concerned with Ontario’s wastewater surveillance program, stated BA.2.75.2 and BQ.1.1 have been detected in Canada however have not taken off, whereas XBB is one to observe.

“XBB would not actually care about your current immune system as a lot as the opposite strains and so it is a fairly important immune escape,” he stated, including that Singapore is at the moment in an XBB-driven wave driving hospitalizations up regardless of very excessive vaccination charges

“The stress on the health-care system doubtlessly with XBB from what we’re seeing with Singapore proper now is frightening.” 

Andrew Croxford, an immunologist primarily based in Zurich, stated subvariants like BQ.1.1 and XBB are being watched carefully as a result of they’re “displaying potential to generate waves of an infection,” however they aren’t more likely to threaten our safety towards extreme sickness.

“They are going to encounter an ever-increasing wall of hybrid immunity in most nations, lowering the potential amplitude. I do not see any ‘again to sq. one’ variants within the present crop beneath surveillance,” he stated.

“I anticipate safety from extreme illness to be largely maintained, with the potential exceptions of the severely immunocompromised and most frail.”

The newest nationwide immunity information from the federal authorities’s COVID-19 Immunity Job Drive (CITF) exhibits that whereas an estimated 62.5 per cent of the inhabitants has had COVID up till the top of August, there are nonetheless tens of millions of principally older Canadians who have not.

The Public Well being Company of Canada stated in an announcement to CBC Information that roughly 4 per cent of circumstances detected in Canada are BQ.1.1, three per cent are BA.2.75.2 and fewer than one per cent are XBB — however the reporting of virus sequence samples is weeks behind in Canada.

Canada’s chief public well being officer stated Tuesday she is making ready for the potential of a variant rising in Canada that might have “very distinct immune escape,” one which vaccines or remedies do not work towards and may evade safety towards extreme sickness. 

“That is one of many worst case situations,” Dr. Theresa Tam stated throughout an look earlier than MPs on the Commons well being committee. “We’ve not detected a type of but, however we have to be ready for the potential.” 

Chief Public Well being Officer of Canada Dr. Theresa Tam takes half in a videoconference throughout a information occasion on the COVID-19 pandemic. (Justin Tang/Canadian Press)

‘Sleepwalking on a tightrope’

Prime Minister Justin Trudeau this week urged Canadians to get each their flu photographs and COVID-19 boosters as quickly as doable, with a purpose to keep away from the necessity for additional precautions and alleviate strain on the health-care system this fall and winter.

“If we’re capable of get a excessive sufficient degree of vaccination, we scale back the hazard of getting to take different well being measures to be sure that we’re all secure and never overloading our hospitals,” Trudeau stated at an announcement in Kanata, Ont., on Monday.

However Canadians are lagging on boosters, with simply 18 per cent of the inhabitants choosing a shot prior to now six months and simply over 50 per cent getting any booster in any respect — even with up to date bivalent vaccines out there that concentrate on Omicron and the dominant BA.4 and BA.5 strains.

“We’re sleepwalking on a tightrope today,” stated Dr. David Naylor, who led the federal inquiry into Canada’s nationwide response to the 2003 SARS epidemic and now co-chairs the federal authorities’s COVID-19 Immunity Job Drive. 

“There have been excessive hopes that the provision of the brand new bivalent boosters would strongly inspire those that haven’t had a 3rd shot. That hasn’t materialized, and it is trigger for concern — particularly if Omicron have been ever to mutate in the direction of better immune evasiveness and elevated virulence.” 

Naylor stated if a variant that carries important threat of extreme outcomes takes off and begins to overload our precarious health-care programs, the failure to impose selective masks mandates could be a significant dereliction of public well being and political management.

Ontario’s Chief Medical Officer of Well being Dr. Kieran Moore stated final week that he would suggest the return of masks mandates if the province’s well being care system turns into too strained — simply as Ontario reported the single highest weekly loss of life depend since early Could

“We do not have sufficient folks taking over the vaccine, most individuals do not wish to put on masks anymore — the circumstances exist which are ripe for an overrun of our health-care system,” stated Arts, on the College of Western.

“I do not know what the magic reply is aside from mandates and folks don’t need mandates so I believe we’re in for an extended winter.”

Folks cross the road in entrance of the Legislative Meeting of Ontario in Toronto on April 27. Ontario’s Chief Medical Officer of Well being Dr. Kieran Moore stated final week that he would suggest the return of masks mandates if the province’s well being care system turns into too strained. (Evan Mitsui/CBC)

Vaccines finest safety towards future surge

However regardless of a latest lack of urgency from the general public to get vaccinated and combined messaging from public well being officers to encourage elevated uptake, the time to arrange for COVID and flu season is now — and vaccines are nonetheless our greatest line of defence.

The Nationwide Advisory Committee on Immunization (NACI) recommends most Canadian adults must be ready as much as six months or so earlier than getting one other shot, or round three months in conditions the place the danger of great sickness is increased. 

“Irrespective of what number of doses you’ve got had beforehand, so long as it has been at the very least three months out of your final dose and at the very least a month or so from a identified an infection, you need to be getting your bivalent booster now,” B.C. Provincial Well being Officer Dr. Bonnie Henry instructed CBC Information in a cellphone interview. 

“Getting a booster dose now could be actually, actually necessary for these subsequent few months.” 

Dr. Allison McGeer, a medical microbiologist and infectious illness specialist at Toronto’s Mount Sinai Hospital, stated the shortage of booster uptake in Canada has been “worrying” to this point, which she attributes to confusion over messaging round ready three or six months. 

“Sufficient folks aren’t going to hit their six months till the top of November and December, once we could be into the wave already in a major approach. Now could be a extremely good time for us to get previous the six month rule,” she stated. 

“You understand having just lately had a COVID vaccine reduces your threat of sickness, lengthy COVID, critical sickness and loss of life. Why would you wish to wait?” 

Henry, who additionally chairs the Council of Chief Medical Officers of Well being, stated she’s frightened Canada’s health-care system might be beneath extra strain within the coming months — not solely due to COVID hospitalizations, but in addition flu and health-care employees getting sick.

“That is why it is so necessary for all of us to make use of all of our instruments like being away from others if we’re sick ourselves and getting the vaccines,” she stated. “That is our primary factor we are able to do.” 

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