N.B. reports no cases yet of new Omicron subvariant XBB.1.5 spreading rapidly in U.S.

A new Omicron subvariant quickly gaining ground in the United States has not yet been detected in New Brunswick, says the Department of Health.

But at least three cases have now been confirmed in Atlantic Canada as of Thursday — two in Nova Scotia and one in Newfoundland and Labrador.

The Centers for Disease Control and Prevention has projected XBB.1.5 will soon represent about 40 per cent of confirmed U.S. cases. That's double from the previous week and up from just 1.3 per cent of new cases only a month ago.

XBB.1.5 was first detected in October, according to World Health Organization (WHO) officials, and has now been identified in 29 countries.

In the U.K., surveillance data suggests it represents one in 25 COVID-19 cases, and could eventually become the next dominant strain.

Asked how concerning this is, particularly after holiday travel and gatherings, Department of Health spokesperson Adam Bowie did not respond directly.

"Public Health has seen fluctuations in the prevalence of various subvariants over the course of the pandemic, but it continues to sequence for subvariants," he said in an emailed statement.

XBB.1.5 is an offshoot of XBB, which evolved through a recombination of Omicron BA.2.10.1 and Omicron BA.2.75. This happens when someone is infected by two strains at the same time and they combine within their host during the viral replication process to form a new variant.

Information about XBB.1.5 is limited, but the World Health Organization is concerned about the subvariant's growth advantage and apparent ability to escape immunity, Dr. Maria Van Kerkhove, the technical lead for the organization's COVID-19 response, told international media Wednesday.

There's no indication it causes more severe illness, she added.

Much uncertainty

Colin Furness, an infection control epidemiologist and assistant professor with the faculty of information at the University of Toronto, suspects XBB.1.5 is more transmissible than previous strains and better at evading the protection provided by COVID-19 vaccines and prior infections, based on the spread in the U.S.

"Is it going to actually present differently? Is it going to attack different parts of the body more, is it going to be more upper or lower respiratory tract? There's so many differences that have happened with variants and subvariants that we kind of need to wait and see," he said.

"And I know that's not a very satisfying answer, but I think uncertainty is the main thing. Could there be more or less virulence? Maybe."

It's "enormously difficult" to draw conclusions about new strains early on, said Furness, and he believes this one may be even harder and take longer, largely because fewer people are getting tested or seeking medical assistance.

He also cited government fatigue, science fatigue and a "cacophony of biodiversity" of subvariants.

"In other words, we don't seem to be as well set up to quickly learn about these variants [as] we were two or three years ago."

If XBB.1.5 were spreading quickly in Canada and causing more severe illness, Furness worries about how long it will take to determine.

"I'm concerned about the fact that we're kind of flying blind," he said. It gives governments less time to react — less time to do public messaging about protective measures, such a promoting vaccines, or even consider providing masks to people, he added.

Fear of cumulative harm

Furness also worries about the damage COVID is causing to people's bodies. He said there's good evidence COVID depresses the immune system for a period of time, which makes people more vulnerable to other illnesses, such as the flu or respiratory syncytial virus, commonly known as RSV.

"I think if we have another wave, people are getting COVID one more time … there's possible cumulative harm here," he said.

"Essentially you're getting a less healthy population."

Dr Christopher Labos, a Montreal-based cardiologist with a degree in epidemiology, said XBB.1.5 could spell trouble for the province's already taxed health-care system.

If XBB is similar enough to other strains that people still have a good antibody response from vaccines or infection, "it may not cause a major disruption," he said.

But each new variant looks a bit different, which means the antibodies people have in their bloodstream are less likely to stick to the virus and help their immune system fight it off. 

"If it's different enough from what came before, and if we don't have very good uptake of booster shots, which we don't … there is the potential that we could see a surge in cases," Labos told CBC's Information Morning Moncton.

"I know a lot of people are behaving as if COVID is over, but we could see a surge again and it's not something our health-care system is going to be able to withstand very easily."

Labos said people do still have some protection from the vaccines they've received, particularly if they got a bivalent booster within the last six months.

Masking and indoor air quality

Masking in indoor public spaces can also "make a big difference" in minimizing the chance of people getting sick, he said.

Many people, however, have "gotten lulled into this false sense of security," based on the messaging from public health officials, said Labos.

"If you tell people it's optional, a lot of people are going to interpret that to mean it's not necessary," he said.

Improving indoor air quality would also help curb the spread of the virus, Labos said. "You know, there's a reason we don't have cholera anymore — it's because we cleaned the water."

"So we need to, number one, acknowledge that COVID is airborne, that it's primarily spread via [us] breathing the same air as other people, and actually do something about it. Because it's not hard to upgrade the ventilation status of our buildings," such as schools, offices and other places where people congregate for long periods of time. "It just takes time and money and an actual will to do so."

No detailed breakdowns

As it stands, New Brunswick isn't regularly releasing detailed breakdowns of COVID-19 subvariants.

The weekly COVIDWatch report provides a breakdown of the five "major branches" of the Omicron variant — BA.1, BA.2, BA.3, BA.4, and BA.5, each of which may have subvariants.

If the department determines there is a change of significance, or if there is value in sharing additional information about a certain variant, it may adjust the way it shares its data.- Adam Bowie, Department of Health spokesperson

This breakdown is meant to inform the public about "the most commonly spreading strains of the virus at any given time," the Department of Health spokesperson said, noting there have been more than 100 genetic sequences of COVID-19 detected in the province since the beginning of the pandemic.

"If the department determines there is a change of significance, or if there is value in sharing additional information about a certain variant, it may adjust the way it shares its data through its regular COVIDWatch reports," Bowie said.

"As Public Health stated leading into the holidays, it's recommended that New Brunswickers take steps to reduce their risks of contracting and/or spreading respiratory illnesses — such as staying home when sick, donning a mask when visiting crowded public places, and washing their hands after coughing or sneezing, especially before touching common surfaces," he said.