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New Delta subtypes a 'concern' but likely won't bring COVID resurgence: specialist

Dalhousie University's Dr. Lisa Barrett says these new descendants of the Delta variant could lead to new variants if COVID-19 cases continue rising
COVID-19 Virus Structure
The structure of the COVID-19 virus

As two new descendants of the Delta variant dominate COVID-19 cases in many parts of Canada, an infectious disease specialist said it's a "concern" but they likely won't bring a large resurgence of the virus.

These two new descendants, often called sub-variants or subtypes, have been dubbed AY.25 and AY.27.

Both were first detected in Canada in the spring, and cases of the subtypes have been diagnosed in every province except Prince Edward Island.

The highest number of cases of the subtypes appear to be in Western Canada with AY.25 becoming the dominant strain in Saskatchewan, followed by Alberta and British Columbia.

In Ontario, AY.25 accounted for 31 per cent of 1,670 confirmed cases of COVID-19 sequenced over a recent four-week period.

While the subtypes appear to be slightly more transmissible, scientists are still uncertain about the reason for their rising growth and their greater effect on COVID-19.

Dalhousie University's Dr. Lisa Barrett said these subtypes haven't deviated enough from the Delta variant for scientists to give them new Greek letter names but they're different enough that they're distinct from the other variants.

The infectious disease specialist added that it's likely these new subtypes aren't as competitive or aggressive, unlike the Delta variant which quickly took over from the Alpha, Beta and Gamma variants.

She told CityNews Halifax that scientists expected the Delta variant to eventually change.

And while it might not sound like a huge issue, she said it's still a concern.

"The more your virus shifts and drifts, particularly away from your own immune response or your vaccine immune response," she said, "the chances are that you may start to have slightly different or under protection."

She said she doesn't think this variant is going to cause a resurgence of COVID-19 cases. However, she said it could lead to another variant if case numbers continue shifting and rising.

She said that at this point in a pandemic, it's not a good idea to just let cases ride since vaccination rates are high.

As of Nov. 12, 83.4 per cent of Nova Scotia's population has received at least one COVID-19 vaccine dose; 78.9 per cent of the province's population is fully vaccinated.

Canada's data, which is set to update on Nov. 15, shows that 77.7 per cent of the entire population has received at least one dose while 74 per cent is fully vaccinated.

Before more restrictions and safety measures can be amended, Dr. Barrett said there must be a couple of "respiratory seasons" where there's a large number of fully vaccinated people around the world and some time for COVID-19 variants to come and go.

In turn, these two things should help add layers of natural immunity.

"That's when you start to get to the situation where you treat it like flu or other endemic viruses," Dr. Barrett said. "It's not that we're talking lockdowns forever, but I don't think our human behaviour is entirely ready to get entirely back to normal.

"As we go forward, reformulation of vaccines is probably going to become a thing for each season."


Chris Stoodley

About the Author: Chris Stoodley

Chris was born and raised in Halifax. After graduating from the journalism program at King's, he started as CityNews Halifax's weekend editor.
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