As Quebec vows to screen for coronavirus variants, some experts say it isn't enough

·5 min read
According to provincial authorities, there have been at least 48 cases linked to COVID-19 variants in Montreal so far.
According to provincial authorities, there have been at least 48 cases linked to COVID-19 variants in Montreal so far.

(Ryan Remiorz/The Canadian Press)

As more contagious COVID-19 strains continue to emerge in Quebec, experts warn the province's recent downward trend in cases and hospitalizations could quickly be reversed, and the government is scrambling to adapt.

On Thursday, Health Minister Christian Dubé said the presence of variants in the province is becoming increasingly alarming.

"Hospitalizations have been going down for a few weeks now," said Dubé. "On the other hand, the trend is fragile. The arrival of the new variants could quickly change that situation."

Experts say Quebec is likely to follow the trend elsewhere in the world — in which the new strains become dominant over a short period of time — and some say the province's reopening plans need to be quickly reconsidered.

"Based on what has happened elsewhere in the world, it is expected that the B117 variant will be the major circulating variant in a couple of weeks," said Prativa Baral, an epidemiologist and doctoral candidate at Johns Hopkins University's Bloomberg School of Public Health, referring to a variant first detected in the United Kingdom.

"There are strategies that we can take right now to ensure that this doesn't happen," Baral said. "But because we've started reopening, my concern is that unfortunately that is the direction we are going in."

The B117 variant is believed to be roughly 50 per cent more transmissible from person to person than the strains currently dominant in Quebec.

Canada needs to do better than the U.K. and South Africa did in dealing with these strains, said Dr. Marina Klein, a professor of medicine at McGill University.

"These countries have not reacted well," Klein said. "And unfortunately, we're making the same mistakes, especially with partial containment measures, which allow for high community transmission. There is already talk of reopening, but with about 1,000 cases per day in Quebec and Ontario, it's still too much, especially with the appearance of variants."

Quebec's decision to reopen retail establishments, as well as indoor dining in orange zones, is of great concern, Baral said, because the variants are much more infectious and can spread much more quickly.

"A lot of the progress we've made over the last couple of weeks could be easily taken away," she said.

Quebec public health director Dr. Horacio Arruda announced Thursday that Montreal is dealing with at least 48 confirmed or presumptive cases of a variant strain, the vast majority of them involving the B117 variant.

Public health officials in the Abitibi-Témiscamingue region previously confirmed two cases of the variant originally found in South Africa, also known as B1351, dating back to early January. (They say the situation related to those cases has been contained.)

Across Canada, hundreds of cases associated with variants originating in the U.K., South Africa or Brazil have been detected.

While that number may seem low, for each detected case there can easily be 50 to 80 more that have gone unnoticed, said Caroline Colijn, a mathematician at Simon Fraser University who has modelled the presence of variants in the country.

What needs to be done

Baral said the public health guidelines that have been in place since the start of the pandemic — handwashing, physical distancing, wearing masks — remain highly effective means of reducing transmission.

But stopping the spread of the variants involves going beyond just postponing reopening plans.

"From a scientific perspective, what has worked in places around the world has been to lock down fiercely," she said. "Lock down for a short period but enforce it very strongly so that you drastically reduce the community transmission and then reopen when community transmission is much lower."

Experts continue to urge the government to analyze more samples for the presence of the variants.

Genomic sequencing can detect all mutations, including new ones, but can take more than a week to deliver results. The B1351 variant cases were confirmed in Abitibi-Témiscamingue fully three weeks after the infections occurred.

Quebec's goal is to roughly double the amount of positive COVID-19 tests it sequences, to 15 per cent, in the coming weeks.

In the meantime, the province is vowing to increase its rate of PCR screening. That method is much faster than sequencing but also less precise: it can confirm the presence of one of the three variants of concern, without identifying which one, usually within 24 hours.

The province's goal is to screen 100 per cent of positive tests in Montreal by the end of next week.

"We need to do both. We need to continue the sequencing because today we know about three new variants but maybe it's going to be five or seven," said Dubé. "But now that we know those three, let's make sure that we screen quickly when we have an outbreak."

As it currently stands, only five labs in the province can screen specifically for a mutation the B117 and B1351 variants share, which will not be enough to keep up if the strains proliferate.

For that reason, Montreal public health now treats suspected variant cases as though they have been confirmed.

"We can't wait for sequencing results, which might come a week or a week and a half later," Dr. Mylene Drouin, the city's director of public health, said Wednesday. "The window of opportunity to intervene will have passed."