'Waning immunity' a factor in N.W.T.'s COVID-19 outbreak, says top doc

One of the first jurisdictions in Canada to administer COVID-19 vaccines is also the first to see their effectiveness wearing off. 

While the majority of the Northwest Territories's COVID-19 cases that have severe outcomes, like hospitalizations and ICU admissions, are still in the non-fully vaccinated population, more cases are showing up due to "waning immunity," said Dr. Kami Kandola, the territory's chief public health officer, speaking to CBC's Heather Hiscox, host of Morning Live.

N.W.T. began vaccinating elders starting on Dec. 31, 2020. By March 6, the health minister reported that half of all adults had been vaccinated. The following week, vaccinations were opened to the general public in the capital, the last community to be offered the shots (because it's the closest to health resources). 

That early administration of vaccines has helped keep the number of its eligible population aged 12 years and up who are fully vaccinated to outpace the national average, at 89.3 per cent, according to CBC's vaccination tracker, compared to 81.6 per cent Canada-wide.

As a whole, 75 per cent of the territory's total population has been vaccinated, compared to 71.3 per cent in Canada as a whole.

Kandola said the territory, which is experiencing a delta-driven fourth wave, could be a beacon of what's to come in other regions. 

"When you look at Israel, when you look at the U.K. when you look at the U.S., you have to factor in, unfortunately, waning immunity six to eight months after people who received the second dose," Kandola said. "Be prepared."

Record number of cases

N.W.T. posted a record number of COVID-19 cases Tuesday evening, with 378 active cases. Kandola said they are "100 per cent driven" by the delta variant, a highly infectious strain of the virus. About 70 per cent of cases with severe outcomes are in those who are not fully vaccinated, she said.

Kandola had anticipated the waning immunity. In mid-September, she told CBC News the issue was already emerging.

"Because we were privileged to get the vaccine first, we unfortunately are going to be the first one to experience the waning immunity, which we're seeing in our own case numbers," she said then.

Booster shots could help

Dr. Andrew Morris, an infectious diseases specialist at Toronto's Sinai Health and University Health Network, said  waning immunity could start to be an issue for Canada around late October.

Whether provinces anticipate this and offer people booster shots to try to head off the potential problem, remains a question, he said.

"If all the governments in Canada say they're going to wait to boost until we sort of see the vaccines aren't working any longer, it could kind of be a little bit too late," he said.

The N.W.T. has already administered third doses to immunocompromised residents and given boosters to those in long-term care. 

"When I'm looking at what's happening, my main priority is to avoid severe outcome [cases]," Kandola said.

She said N.W.T. is now administering boosters in Yellowknife and Behchokǫ̀ — the hardest-hit communities right now — to those of 75 and older and giving boosters to its frontline staff.

Pressure on health system

Kandola said the territory still has not reached the peak of infection for Yellowknife and Behchokǫ̀, though health orders and gathering restrictions are in place in both communities, with schools closed to in-person learning for several weeks. 

Kandola said the high rate of cases is "placing a significant pressure" on the territory's medical system. In the last six weeks alone, there have been 36 hospitalizations, where prior to that, throughout the whole pandemic, there had only been four hospitalizations. There have also been six deaths in the last six weeks, and a total of 13 ICU admissions.

"This is a huge system demand. In addition, most of our critically ill patients that need further care are sent to Alberta and Alberta is also stretched," she said.

The containment orders and gathering restrictions in places hasn't fully stopped hospitalizations, Kandola said, but "we're able to keep it under control."

"If I were to lift the orders, it would overwhelm the health hospital system for sure."