The concern Manitoba doctors have about the delta variant

In a matter of days, the number of cases of the delta COVID-19 variant has surged in Manitoba.

The COVID-19 mutation is considered a variant of concern by the World Health Organization -- even more transmissible than the B.1.1.7 or alpha variant.

The most recent numbers from the province show there are 61 delta cases in Manitoba, with at least one case in each health region.

Some scientists are concerned that the variant is so easily spread and one vaccine dose may not be enough.

"We talk about these variants and discuss them not because we're trying to scare people, but because I think we are generally concerned," said Jason Kindrachuk, a University of Manitoba virologist and Canada research chair of molecular pathogenesis of emerging & re-emerging viruses.

Kindrachuk says delta's specific mutations aren't well known yet but the epidemiology so far suggests it has the potential for dangerous levels of spread and it could be at least 40 per cent more infectious than the alpha variant of concern, which is currently fuelling Manitoba’s third wave.

“Now we're dealing with a variant that is more transmissible than the last, more transmissible variant,” he said.

Dr. Anand Kumar, an attending intensive care unit physician in Winnipeg and infectious disease specialist told CTV News Tuesday that he thinks the delta variant could be explosive and public health orders need to stay in place longer.

He said it took six weeks for third wave cases to escalate in Manitoba, as the province's reopening happened when test positivity was five per cent and daily case counts were about 100.

“In order to keep this suppressed, we need to let the numbers go down significantly, further than that before reopening, and then we'd have to reopen very slowly to make sure we were in good shape,” Dr. Kumar said.

Another concern about the variant is vaccine effectiveness.

"We know now that 70 per cent will not be enough to reach herd immunity,” said Dr. Joss Reimer, medical lead for Manitoba’s Vaccination Implementation Task Force, in reference not to just the delta variant, but all variants of concern.

“We, certainly on the task force, have no intention of stopping at 70 per cent and really do intend to reach, you know, 80 per cent or 90 per cent of Manitobans,” she said.

Dr. Reimer said it is not clear what percentage will be needed to hit textbook herd immunity against the delta variant.

She added in Manitoba, people over 80 years old have reached that 90 per cent vaccination mark.

“And so, we are going to continue to work towards that, because even if we reach the number that the delta variant requires, that might not be sufficient for the epsilon variant that potentially comes around the corner next,” Reimer said.

She also said the science on single-dose effectiveness against the delta variant, so far, is hard to interpret because some participants may not have had enough time to fully build up antibodies.


"But with two doses, most of the data so far shows us that there might be a slightly reduced effectiveness, but there is still, like, a very strong protection against that variant from the vaccines."

This is why Kindrachuk says getting second doses into arms quickly is so important.

“Unequivocally, the vaccine programs that have gotten people fully vaccinated have worked very, very well," Kindrachuk said.

On Wednesday, Reimer was asked about speeding up the second dose campaign.

She said Manitoba can only move as fast as supply allows and there is not much room to go any faster.

According to Manitoba’s vaccine dashboard, 160,228 second doses of COVID-19 vaccines have been administered in the province as of June 8.