Scientists are closely watching Omicron’s next COVID curveball | CBC News

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• Scientists are closely monitoring new subvariants of Omicron that are better able to evade immunity than previous strains.

• The new subvariants have the potential to power future waves, but protection against severe COVID-19 has held up among the population so far.

• Updated bivalent boosters and population immunity to vaccination and past infections will be put to the test this fall and winter.

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Omicron has completely taken over the pandemic, unleashing massive waves of COVID-19 in Canada and around the world over the past year. Now scientists are trying to answer a crucial question – what could it throw at us next?

COVID levels reached new heights this year as Omicron and its highly contagious subvariants battled for population dominance, leading to a relentless spread of the virus across the country.

However, as Omicron continues to mutate and produce new strains that have been shown to evade immunity better and have the potential to fuel new waves of COVID, scientists are warning that this may not have happened to us.

“The challenge is that we don’t yet understand what else this virus has in store for us,” Michael Osterholm, an epidemiologist and director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told CBC News.

“If you have subvariants that can evade immune protection from previous infections, and you have waning immunity, that could set us up for a whole new set of circumstances.”

Global COVID levels have declined in recent weeks, with cases down 11 percent and deaths down 18 percent, the government said World Health Organization (WHO), but there are some worrying signs that infection rates may soon increase.

A recently Increase in cases and hospitalizations in the UKand a current one Rise of virus in sewage levels in Ontario and Saskatchewan Let scientists prepare for possible autumn and winter waves.

“There could be a huge wave of these variants because they’re going to spread,” said Jeremy Kamil, a virologist and associate professor of microbiology and immunology at Louisiana State University.

“But the possibility that they’re overwhelming hospitals is what I wanted to call people back to because we don’t see any evidence of it.”

New Omicron subvariants are a cause for concern

Omicron has outlasted all other variants due to its ability to rapidly mutate and partially evade immunity, which explains why new subvariants have kept emerging that have completely eclipsed other strains over the past year.

the WHO These omicron subvariants now account for 99.9 percent of sequenced cases worldwide — with BA.5 at 81 percent, BA.4 at 8.1 percent, BA.2.75 at 2.9 percent, while other omicron subvariants account for estimated 7.8 percent are responsible percent of sequenced cases.

The BA.5 subvariant remains the current dominant circulating strain in Canada, accounting for more than 85 percent of cases in the latter state Databut there are worrying new omicron subvariants that scientists are now watching closely for signs of further spread.

Two new sub-variants, BA.2.75.2 and BQ.1.1have evolved from earlier BA.2 and BA.5 strains and carry mutations that have been shown to allow them to better evade immunity from vaccination and previous infections.

A new preprint laboratory study from Sweden, which was not peer-reviewed, found that the Omicron subvariant BA.2.75.2 exhibited “profound antibody flight” against immunity from previous infections, suggesting that it was “comparable to the immunity of antibodies in the population.” can be effectively avoided”.

BA.2.75.2 and BQ.1.1 were also found to be “the most antibody-avoidant” strains tested, “far outperforming” BA.5 in a new one. Preprint Laboratory Study from China, which was not peer-reviewed – which specifically looked at protection from the Sinovac vaccine.

Despite the fact that these two new subvariants only make up a fraction of a percent Of recently sequenced cases worldwide, virologists are concerned that they could potentially fuel future COVID waves, especially given their worrying mutations.

Tom Peacock, a virologist at Imperial College London, said they could trigger future flare-ups because they are structurally different enough from previous wave-causing strains and can also partially elude previous immunity from vaccination and infection.

“Some of these lines are growing pretty fast — these include BA.2.75.2 and BQ.1.1,” he told CBC News. “These combined properties suggest they may have the ability to trigger the next wave of COVID, either regionally or globally.”

If these new subvariants do spike COVID levels again in the future, the biggest unanswered question we face now is how will our immune protection from vaccinations and previous infections hold up to what Omicron throws at us next?

“There is clearly a horse race between these variants to replace each other,” said Kamil. “Whether that means these variants will actually drive a huge wave and in some cases spike we don’t know and it’s too early to say – but it seems possible.”

“Hybrid immunity” is tested

While the vaccine’s effectiveness against serious outcomes has held up well, two-dose protection against Omicron infection fell dramatically compared to previous variants – falling to just 36 percent in December and rising to 61 percent with a booster, it said a new study from Ontario to learn published in JAMA.

This has hit our population’s immunity from vaccination against Omicron infection underlined the need for boosters Earlier this year, and it left us very vulnerable to the Omicron subvariant-powered waves that have been ripping through the populace since then.

New national data found by the federal COVID-19 Immunity Task Force Almost two-thirds of Canadian adults are infectedespecially since Omicron first emerged last December — with younger adults bearing the brunt at more than 73 percent.

“Canada had very limited community transmission of the virus for almost the first two years of the pandemic,” said Dr. Tim Evans, director of the School of Population and Global Health at McGill University and executive director of the task force.

“Omicron changed all of that, and none of us really knew the extent to which it would change that.”

But this level of immunity in the population to vaccination and infection could have a silver lining as we head into the fall and winter – if it lasts.

A new Canadian study published in The Lancet who analyzed protection from vaccination and prior infection found that those with were combined hybrid immunity performed better against future COVID infections.

The study found that two doses of a COVID-19 vaccine plus recovery from Omicron infection provides protection equivalent to three doses, and those protected from both vaccination and infection may be better protected from future reinfection .

dr Gaston De Serres, an epidemiologist at the Quebec National Institute of Public Health and co-author of the study, said that while vaccination offers significant protection against infection and hospitalization, research shows hybrid immunity offers an advantage.

“You have some protection [with vaccination]but infection clearly contributes,” he said, noting that infections can still be serious and should be avoided.

Given that only about 40 percent of Canadians over the age of 60 have had COVID, according to the National immunity dataleaving a large part of the population still more susceptible to infection in the future – especially among newer strains.

“Omicron hasn’t affected everyone equally,” Evans said. “We still have a significant minority of Canadians who have not been infected and they are clustered in the older age groups who are at risk for adverse outcomes [the virus] are the biggest.”

Bivalent vaccines can reduce the risk

Canada recently approved one updated bivalent COVID-19 vaccine which targets both the original virus and the original Omicron variant BA.1, but whether it will help prevent future waves is unclear.

“In terms of how long this protection will last and how it will apply to future variants – unfortunately we don’t have a clear answer on that,” De Serres said.

“We believe that the bivalent vaccines will help reduce the risk of infection with the new viruses, but again, it’s not as if they will be as effective as the vaccine before the arrival of Omicron.”

The new dose does not directly target the dominant subvariants BA.4 and BA.5, which are the The US approved an updated recording for this month. Pfizer and Moderna both submitted applications for Health Canada approval earlier this month for their BA.4-BA.5 5 targeted vaccines.

Meanwhile, public health officials are across the country Prioritizing additional boosters from bivalent vaccines for vulnerable groups, including older Canadians and immunocompromised individuals, in hopes they will provide better immune protection for falls.

“It remains to be seen,” Evans said, as to how well the population’s immunity will hold up. “I think the trend lines are in the right direction and that clearly depends on whether people are well protected either by vaccination or by vaccination and infection.”

How long protection against infections and serious diseases will last even with updated bivalent vaccines and high immunity in the population is unclear, but is expected to be put to the test this fall and winter.

“We don’t know what’s going to happen next. We could go on like this for a few more months and then suddenly see a big change,” said Osterholm. “The immunity we have will certainly hinder that – but how good it is we don’t know.”