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Where is the Delta variant most prevalent in Canada?


With the increasing presence of the Delta variant in Canada, experts say that it will soon become the dominant strain of COVID-19 infections. But, having a larger proportion of the population vaccinated, along with other measures, can help prevent Canada from entering a fourth wave of the pandemic.

As of Tuesday afternoon, there have been more than 4,100 cumulative cases of the Delta variant in Canada, with Ontario accounting for 42 per cent of the cases in the country and British Columbia accounting for 31 per cent.

The Delta variant, also known by its lineage of B.1.617.2, was first identified in India. According to experts it is 50 per cent more transmissible than the original strain and is also more transmissible than the Alpha variant, currently making up 90 per cent of all new infections in the U.K.

“When you have a more transmissible variant – also known as a more fit variant – you’re going to see a takeover,” Dr. Isaac Bogoch, infectious disease specialist, told “It’s more fit than the Alpha variant. It’s more transmissible, and we’re seeing it take over as the more dominant variant here in Ontario and elsewhere in Canada, and quite frankly, in many other parts of the world.”

With a daily average of approximately 166 cases of the Delta variant per day in Canada, is the country at risk of heading into another wave?

Bogoch said that as things open up, there will be more opportunities for transmission, but vaccinations can be one factor in preventing another wave from occurring.

“As we gradually open up, there will be more and more opportunities for the virus to be transmitted. This virus isn’t going anywhere and we know it’s not going anywhere, and if it’s given opportunities to be transmitted, we’ll see cases,” he said. “But the vaccines work against this variant. A single dose is pretty effective. Regardless of the vaccine, it’s pretty effective in keeping people out of the hospital, and of course, two doses are more effective than one.”

Studies show that the Pfizer and AstraZeneca vaccines are more than 90 per cent effective in preventing hospitalizations due to the Delta variant, however there may be some breakthrough infections with the reduction of antibodies in the bloodstream.

Moderna also announced Tuesday that, after a lab study, they found their vaccine to be effective in producing the antibodies needed to fight against the Delta variant.

“There will still be cases among fully vaccinated people, they’ll just be less common. Fully vaccinated people, even if they test positive, are much less likely to have severe illness,” said Bogoch.

Thomas Tenkate, associate professor at the Ryerson University School of Occupation and Public Health, adds that while vaccinations can help curb the spread of COVID-19, Delta variant cases can still increase, especially in unvaccinated people and under-vaccinated communities.

“Those who are partially vaccinated are at greater risk than those who are fully vaccinated of becoming infected with the Delta variant,” Tenkate told Tuesday. “We also have under 12s who are not able to be vaccinated as yet, and the number of people under 19 who have been vaccinated is still relatively low compared with the rest of the adult population. These groups are really the most vulnerable.”

Tenkate said that to avoid another wave, vaccination efforts need to continue and more Canadians need to become fully vaccinated.

“We need to ramp up the proportion of the population who are fully vaccinated and we have to encourage those who haven’t been vaccinated yet with their first dose to do so,” he said. “It is important to reach these unvaccinated people because having the herd immunity rate as high as possible will give us the best change of curbing the Delta variant.”

Dr. Theresa Tam, Canada’s chief public health officer, said Friday that while vaccinations are still underway, “sustained control efforts” are needed, such as wearing masks. The modelling Dr. Tam presented shows that if 80 per cent of the Canadian population is fully vaccinated, it is less likely that a fourth wave will occur.


British Columbia

Of the five health regions in British Columbia, all but the Interior Health Authority and Northern Health Authority have seen a presence of the Delta variant as of June 25. Vancouver Island is currently seeing the most Delta variant cases, with a rate of 21 per cent for every 100 sequenced lab samples. The Fraser Health Authority has a rate of 14 per cent and the Vancouver Coastal Health Authority is reporting a rate of 11 per cent.


Although not all public health units have detailed Delta variant data available, the provincial government listed the following 10 health units as Delta variant hotspots: Toronto, Peel, York, Durham, Hamilton, Waterloo, Halton, Porcupine, Wellington-Dufferin-Guelph, and Simcoe-Muskoka. Ontarians living, working, or going to school in those regions have been able to book an accelerated appointment for their second vaccine dose in order to prevent the spread of the Delta variant.


In Quebec, Montreal is seeing the highest number of Delta variant cases, reporting a cumulative total of 16 cases on Tuesday. Other health regions are currently seeing fewer than 10 cases with the Delta variant.


Of the variants of concern identified in Alberta, the Calgary Zone and Edmonton Zone are seeing the most Delta variant cases. On Sunday, a cumulative total of 588 Delta cases have been reported in the Calgary Zone and 71 in the Edmonton Zone.


The Regina health region leads the province in the highest number of Delta variant cases, reporting 113 cumulative cases Monday. Saskatoon is reporting the second highest number of cases with 30 confirmed Delta variant cases to date. All other health regions have reported fewer than 10 cases.


In Manitoba, the Winnipeg regional health authority is reporting the most number of Delta cases, recording 102 cumulative cases on Tuesday. The Southern Health – Santé Sud region is reporting 62 Delta variant cases and the Northern region is reporting 54.

There have been no Delta variant cases reported in the Prairie Mountain Health region and Interlake – Eastern region.

Note: Atlantic provinces and territories did not have detailed information on Delta variant cases available.


This variant has already set back some countries in their reopening plans.

In the U.S., the Centers for Disease Control and Prevention (CDC) said the Delta variant is now identified in approximately one in every five COVID-19 infections in the country. With the increasing presence of the Delta variant, the Los Angeles County Department of Health is encouraging everyone to wear masks in indoor public spaces.

In Israel, COVID-19 infections involving the Delta variant were four times higher in the past week, with 138 cases attributed to this variant. Now, less than two weeks after lifting the mandatory indoor mask mandate, the Israel health ministry has reversed its decision and announced Friday that masks must again be worn indoors.

In Australia, Sydney and its surrounding cities reported more than 100 cases of the Delta variant on Sunday. Sydney is now in a two-week lockdown which became effective Sunday, while Darwin has mandated a two-day, stay-at-home order. Other regions in Australia have closed their borders and have enforced additional COVID-19 safety protocols, such as stronger physical distancing and mask regulations.

As the Delta variant starts to become the dominant strain worldwide, the World Health Organization (WHO) encourages everyone, including fully vaccinated individuals, to continue physical distancing measures and the wearing of masks. Top Stories

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