White Coat, Black Art·The Dose

Canada has a 'narrow window' for containing delta variant, also known as B1617, warns U.K. expert

U.K. epidemiologist Dr. Deepti Gurdasani says the delta variant, also known as B1617, is driving a new COVID wave in the U.K. — and warns Canadian officials that with delta already in Canada, they need to act fast and roll out those second doses to as many people as possible.

Getting Canadians fully vaccinated is ‘absolutely critical,’ says epidemiologist

People drink and eat in outdoor street dining areas, as lockdown restrictions are eased in London, England, but the delta variant, also known as B1617, is driving a new wave of COVID-19 cases in the U.K. and threatening re-opening plans. (Toby Melville/Reuters)

"Do not let this variant spread. It's a very dangerous variant."

Dr. Deepti Gurdasani, a clinical epidemiologist and senior lecturer in machine learning at Queen Mary University of London, issued this stark warning for Canadian officials about the delta variant, also known as B1617 that was originally identified in India. 

The delta variant, recently re-named by the World Health Organization in an effort to simplify coronavirus variant names, is driving a new wave of COVID cases in the U.K.

"It spread incredibly quickly here [in the U.K.] So in a matter of four to six weeks, it's a variant that has gone from almost not being present here to being the most dominant variant," Gurdasani told Dr. Brian Goldman, host of The Dose and White Coat, Black Art.

Dr. Deepti Gurdasani is a clinical epidemiologist and senior lecturer in machine learning at Queen Mary University of London. (Submitted by Deepti Gurdasani)

There isn't widespread screening for the delta variant in Canada, but the Public Health Agency of Canada says it's in all ten provinces and the World Health Organization has labelled it a variant-of-concern. The strain is also confirmed as the source of some outbreaks here, and experts agree it's likely spreading undetected.

While delta's spread isn't being quantified in Canada, officials here can look to the U.K.'s experience for a glimpse into a possible future if the variant isn't contained.

"What we are seeing in the U.K. is exponential rises in cases associated with higher levels of hospitalization and very early rises in deaths as well," Gurdasani said.

The U.K. experience

While it's not yet known if the virus is more lethal, she said it's likely more transmissible than the alpha/B117 variant, dominant in Canada now, given the rate of spread in the U.K. and elsewhere. 

A temporary coronavirus testing centre is set up in Bolton, England, one of the areas of the U.K. where the delta variant, also known as B1617 and first identified in India, is spreading fastest. U.K. experts warn Canadian officials they need to act fast to stop the spread of this strain. (Peter Byrne/PA via AP)

According to government data, COVID-19 cases in the U.K. rose by almost 35 per cent in the seven days leading up to June 2, and British health officials said the delta variant now accounts for up to 75 per cent of all new infections.

Gurdasani said hospitals are not being overwhelmed at this point, but she's concerned if the re-opening of society continues as it's slated to on June 21, then they could be in trouble, and urged officials there to delay re-opening. 

Officials in the U.K. say they are looking at the data and will announce a decision on June 14 on whether they'll stick to the original reopening timeline.

"We've negligently not taken action early and delayed action as far as possible, which has meant late lockdowns, long lockdowns, and huge disruption to people's lives, the economy and, of course, mass deaths, which has been a key feature of the U.K. response," Gurdasani said.

Two-dose vaccine strategy

The good news is that two doses of the approved COVID-19 vaccines seem to work against this variant, according to a preprint study, which has not yet been peer reviewed. The bad news is that one dose offers diminished protection. 

Researchers at Public Health England studied over 1,000 people confirmed to have the delta strain and found that the Pfizer vaccine was 88 per cent effective and AstraZeneca was 60 per cent effective against the variant two weeks after the second dose.

People in Montreal getting their COVID vaccines in May. Experts are calling on officials to get second doses rolled out as quickly as possible to stave off a fourth wave driven by the delta variant. (Kwabena Oduro/CBC)

However, the study found both vaccines were only about 33 per cent effective against symptomatic disease three weeks after the first dose.

Given these figures, it's "absolutely critical" to get two doses into Canadians as quickly as possible, advised Gurdasani. 

WATCH | Variant found in India linked to U.K. COVID-19 resurgence:

Variant found in India linked to U.K. COVID-19 resurgence

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A resurgence of COVID-19 in the U.K. is linked to the B.1.617 strain first found in India and it has sparked concerns it may delay plans to emerge from lockdown. 1:56

Dr. Zain Chagla, associate professor of medicine at McMaster University and an infectious disease specialist for St. Joseph's Healthcare in Hamilton, agreed, saying Canada needs to make "a monumental effort" to roll out second doses — but offered some comfort in the interim.

While some people in the U.K. got COVID from the delta variant even after being fully vaccinated, they mostly experienced milder illness, he said.

Dr. Zain Chagla, an infectious disease physician for St. Joseph's Healthcare in Hamilton, Ontario, and associate professor of medicine at McMaster University, says he remains optimistic the existing vaccines can fight the COVID-19 variants. (Craig Chivers/CBC)

He also pointed out that Canada's vaccination rate means we're in a far better position now to fight off this variant than we were during the third wave, driven by the alpha variant.

"I think we are ahead of the curve," Chagla said.

"Places like Australia, Taiwan and Singapore who are dealing with this, and are slower to vaccinate their population, they're going to have more trouble. This variant seems to be effective at finding its way to people that have not been vaccinated."

COVID zero?

Gurdasani said the window to contain this variant is "very, very narrow" because once it's dominant in a population, only "very, very strict restrictions" will work to curb its spread.

"So if I were the Canadian government, I would look towards pivoting towards elimination at this point in time, because I think that's the only way to protect vaccine resources and also ensure that some level of control of the pandemic is maintained."

Diners are pictured eating indoors at Yolks restaurant in Vancouver, British Columbia on Tuesday May 25, 2021. Experts say reopening plans could be threatened in parts of Canada if the delta variant, also known as B1617, gains a foothold. (Ben Nelms/CBC)

Gurdasani clarified that by elimination she doesn't mean complete eradication of the virus because that's very difficult — but rather "bringing community transmission to zero or near zero and maintaining it at that level for as long as possible until most of the population is protected with vaccines."


Written and produced by Willow Smith.

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