New Omicron stock on the horizon could trigger future COVID wave

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• Scientists are watching closely for the new Omicron subspecies, which can evade immunity better than previous strains.

• New variants may spark future waves, but protection against severe COVID-19 has collectively held up so far.

• The updated bivalent booster and herd immunity from vaccination and previous infections will be tested this fall and winter.

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Omicron has completely hijacked the pandemic, causing a wave of COVID-19 in Canada and around the world over the past year. Now scientists are trying to answer an important question — what will it tell us next?

COVID levels reached new heights this year, with Omicron and its more virulent variants vying for demographic dominance as the virus spread relentlessly across the country.

But Omicron continues to mutate, creating new strains that have been shown to evade immunity better, and could trigger a new wave of COVID, so scientists say it hasn’t been done yet. I warn you that there is a risk.

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

“If there are subvariants that can evade the immune protection from previous infections, resulting in weakened immunity, a whole new set of situations could arise.”

Global COVID levels have fallen in recent weeks, with cases down 11% and deaths down 18%, according to the World Health Organization. world health organization (WHO), but there are some troubling signs that infection rates may soon recover.

Recent Surge in UK cases and hospitalizationsand recent Virus rise in wastewater levels in Ontario When Saskatchewan Reserve your scientists for potential fall and winter waves.

“These subspecies are so spreadable that they can create giant waves,” said Jeremy Camille, a virologist and associate professor of microbiology and immunology at Louisiana State University.

“But what they could overwhelm hospitals is that I wanted to call people back because there were no signs of that.”

New variant of Omicron raises concerns

Omicron outlasted all other variants due to its ability to mutate rapidly and partially evade immunity. This explains why the past year has seen the consistent emergence of new sub-variants that completely outperform other strains.

WHO Omicron subvariants currently account for 99.9% of sequenced cases worldwide, with BA.5 accounting for 81%, BA.4 for 8.1%, BA.2.75 for 2.9%, and other Omicron subvariants Subvariants account for an estimated 7.8%. Percentage of cases sequenced.

The BA.5 subvariant remains the predominant circulating strain in Canada, accounting for more than 85% of recent federal cases. databut there is a new Omicron subvariant that scientists are now closely monitoring for signs of wider spread.

two new subvariants, BA.2.75.2 and BQ.1.1evolved from previous BA.2 and BA.5 strains and carries mutations that have been shown to allow better evasion of vaccination and immunity from previous infections.

New preprint lab study Non-peer-reviewed Swedish researchers found that the Omicron subvariant BA.2.75.2 had “severe antibody evasion” against immunity from previous infections, suggesting that immunity from antibodies within the population suggests that it may be possible to “effectively avoid”

BA.2.75.2 and BQ.1.1 were found to be the ‘most antibody-evading’ strains tested. Preprint Lab Study From China, which has not been peer-reviewed Sinovac vaccine.

These two new subvariants are percent fraction Of the recently sequenced cases around the world, virologists fear it could trigger future waves of COVID, especially given the concerning mutation.

Tom Peacock, a virologist at Imperial College London, said the virus is structurally sufficiently different from strains that have caused previous waves that it may partially escape previous immunity from vaccination and infection. said it could trigger a future surge.

“Some of these lineages are growing fairly quickly, including BA.2.75.2 and BQ.1.1,” he told CBC News. “These combined characteristics suggest that they could trigger the next wave of COVID, either regionally or globally.

If these new variants raise COVID levels again in the future, the biggest open question we face now is whether vaccination and immune protection from previous infections will be what Omicron throws next. It’s about how you can endure it.

“There’s clearly a horse race going on between these subspecies to replace each other,” Kamil said. I don’t know if that means the numbers will skyrocket, and it’s too early to say, but it seems possible.”

‘Hybrid immunity’ to be tested

Vaccine efficacy remains well-maintained for severe outcomes, but two-dose protection against Omicron infection has dropped dramatically compared to previous variants, according to the new Ontario province. It dropped to just 36% in 2018 and rose to 61% with a booster. study Published in JAMA.

It hit our population immunity from vaccination against Omicron infection Emphasize the need for boosters Earlier this year, it became highly susceptible to the wave fueled by the Omicron subvariant that has since ripped apart the population.

new country data Discovery from the Federal COVID-19 Immunity Task Force Nearly two-thirds of Canadian adults are infectedThis is largely due to the fact that 73% or more of young adults have been affected since Omicron first appeared last December.

“Canada had very limited population transmission of the virus during the first two years of the pandemic,” said Tim Evans, Ph.D., director of the Department of Population and Global Health at McGill University and executive director of the task force. said.

“Omicron changed all that, but no one knew how much it would change.”

However, public immunity levels against immunizations and infectious diseases may be showing signs of improvement in the fall and winter.

New Canadian study published in The Lancet In studies that analyzed protection from both vaccination and previous infection, hybrid immunity Well done against future COVID infections.

In this study, two doses of the COVID-19 vaccine and recovery from Omicron infection provided protection equivalent to three doses, and those who were protected from both vaccination and infection were more likely to be protected against future reinfection. It turns out that you may be more protected.

Dr. Gaston de Ceres, an epidemiologist at the Quebec National Institute of Public Health and study co-author, said vaccination provided significant protection against infection and hospitalization, while the study showed hybrid immunity. said. provides the edge.

“You have some protection [with vaccination]but obviously being infected adds a lot,” he said, pointing out that infections are still serious and should be avoided. I think is very well demonstrated here.

But given that only about 40% of Canadians over the age of 60 were found to have COVID, National immunity datait still leaves a large subset of the population more vulnerable to future infections — especially in new strains.

“Omicron didn’t affect everyone equally,” Evans said. “There is still a sizable minority of Canadians who have not been infected, and they are clustered in older age groups. [the virus] it’s the best. ”

Bivalent vaccine may reduce risk

Canada recently The latest bivalent COVID-19 vaccine It targets both the original virus and the original Omicron variant BA.1, but it is unknown if it will help prevent future waves.

“In terms of the duration of its protection and how it applies to future variants, unfortunately there is no clear answer to that,” said De Serres.

“We believe a bivalent vaccine would help reduce the risk of infection from the new virus, but again, it would not be as effective as the vaccine before Omicron’s arrival.”

The new dosage does not directly target the dominant subvariants BA.4 and BA.5. US approved updated shots for this month. Pfizer and Moderna earlier this month he submitted Health Canada’s application for approval of the BA.4-BA.5 five-target vaccine.

Meanwhile, public health officials across the country Prioritize additional boosters for bivalent vaccines We hope to provide better immune protection heading into the fall for vulnerable groups, including older Canadians and those with weakened immune systems.

“We still have to wait and see,” Evans said as to how well herd immunity will be maintained. It’s a function of people being well protected either by vaccination or by infectious diseases.”

Even with the latest bivalent vaccines and high levels of immunity in the population, it is unclear how long protection against infection and serious illness will last, but it could be tested this fall and winter.

“I don’t know what else is going to happen. If this continues for a few months, we might suddenly see a big change,” Osterholm said. “The immunity we have would certainly provide some barrier against it – but I don’t know how good it would be.”