The next COVID wave is already starting in Canada. Here’s why this one should be different

COVID-19 is ticking up again and the country is barely into fall.

That shouldn’t come as a surprise, said McGill University genomic evolutionary biologist Jesse Shapiro. Forget, for a moment, all the alphanumeric subvariants, new and old, scientists are watching. “Even just based on waning immunity, the time since the average person had their last infection or their last booster, a wave was expected,” Shapiro said.

In most provinces, immunity isn’t as high as it could be, which is why Canada’s public health agency is appealing to people to get “up to date” with their vaccines. New bivalent shots that target the original SARS-CoV-2 strain, as well the original BA.1 strain of Omicron, are being rolled out, though Health Canada has yet to approve bivalent boosters targeting the BA.4 and BA.5 strains, which, along with BA.2, are currently the major circulating strains in Canada.

Infections and hospitalizations are inching up in Quebec, Alberta, and British Columbia, but wastewater signals are falling in Saskatchewan. Public Health Ontario reported Friday that it’s seeing a gradual increase in cases and the number of tests coming back positive, when looking back over the past two weeks. Ottawa is already in a “new wave” of COVID-19, the city’s public health department declared last week.

COVID-19 is persisting at a fairly high rate of infection across the country, experts said. “Here in British Columbia, it’s estimated we’re under-reporting cases by 100-fold,” said University of B.C. evolutionary biologist Sarah Otto who, like Shapiro, is a member of Canada’s national Coronavirus Variants Rapid Response Network, or CoVaRR-Net.

Based on the network’s data sharing, Shapiro predicts that, one by one, the provinces will acknowledge another wave. “As usual, it’s hard to say, will this be a big wave? Will it be a small wave. For sure it’s a wave of some kind.”

Should we worry? Science magazine dropped a piece last week warning one or more of several highly immune dodging strains of SARS-CoV-2 — “may well cause big, new COVID-19 waves this fall and winter.” What it means in terms of severe disease and deaths, Science said, is very much an open question.

What we’re witnessing is a vast amount of convergent evolution, said Shapiro, an associate professor in McGill’s department of microbiology and immunology and the Genome Centre. Many of the variants have the same mutations, or combination of mutations, on key sites of the viral genome that allow them to spread more easily in a highly immunized population.

Natural selection is favouring the same mutations, over and over again, Shapiro said. “It’s increasing evidence that they are doing something, and what that something is, is probably to evade immunity. So, they’re even better at re-infecting people.”

“They are basically less easily recognized by the antibodies that are in the majority of people right now,” Otto said.

The good news is that the none of the subvariants are totally unique. If they were, “that would be worrying, in a different way,” Shapiro said. Omicron came out of nowhere, a deep branch of SARS-CoV-2’s bio-genetic tree. The new lineages or subvariants are descendants of Omicron.

“I don’t want to underplay what this virus has been putting us through — it clearly is able to evolve in all kinds of different directions and surprise us,” Shapiro said.

“But it’s encouraging that we are seeing the same mutations, repeatedly. Which suggests, at least for now, a limited supply of adapted mutations.”

“It’s kind of saying that the virus is constrained. It’s hobbled a little bit,” Otto said.

Another positive, according to Otto, is that, even if antibodies circulating in blood are waning, “COVID now, for almost all of us in Canada, is a disease our immune system recognizes.”

“So, when we get infected, if we don’t have antibodies in our bloodstream currently, we have memory cells that remember this virus, that remember SARS-COV-2, and kick into action.” Those memory immune cells can produce new antibodies, as well as kill infected cells, shortening the course of the infection for many people and protecting against severe disease.

The risk of hospitalization, per infection, is low. “The bad news is that COVID is still rampant at the moment,” Otto said. People are still being hospitalized; people are still getting long COVID. “So, that first wave of protection — having antibodies that recognize and prevent you from getting infected in the first place — is still the one we want to go for.”

None of the new variants are circulating at high levels in Canada. Some worry that BQ.1.1, which Otto said has a striking constellation of changes that increase the ability to evade antibodies, could sweep through populations, as if nobody has any immunity. “I don’t think that’s going to be the case, based on what I’ve seen so far,” Otto said. “It’s just helping the virus spread a little bit, not game-changer amounts.”

“But it’s too early to know for sure.”

Ontario and B.C. have begun moving people out of hospital in the event of a surge in COVID, in flu, or both, a sign the provinces are worried enough about hospital capacity to make room, Otto said. Ontario’s new law, Bill 7, allows hospitals to move patients awaiting long-term care to nursing homes not of their choosing, and as far away as 150 kilometres away.

Shapiro knows the perils of trying to forecast the future with a virus as wily as SARS-CoV-2. “My crystal ball is my fantastic other colleagues with CoVaRR-Net. All credit to all these people who are sharing data and analyzing it.”

But, “if you are a few months from your past infection or past vaccine, go get your booster,” he said. “The more immunity we can get in the population, the less bad this wave will be in terms of overall transmissions and hospitalizations, and bad outcomes we want to avoid.”

Canada’s panel of immunization advisers recommends people aged 12 and older get a fall booster dose, regardless of how many they have already received, three to six months after their last vaccine or infection.

National Post

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