Three weeks after Omicron appeared in Quebec, it now makes up 80 per cent of cases

Quebec only detected its first Omicron case on Nov. 29, but the new variant already accounts for about 80 per cent of the province's cases, the public health authorities announced Tuesday.

In fact, that rise to dominance happened even more quickly when you look at specific milestones over that period, wrote the Institut national de santé publique du Québec (INSPQ) in an overview of its efforts to keep up with the pace of the spread.

An "unfinished" Dec. 14 screening project found Omicron to be "at least" 28 per cent of cases at that point, the institute wrote.

The organization quickly moved on anyway to a new screening strategy and a week later, is estimating that Omicron has already reached the 80 per cent level.

Its new lab-testing strategy "reveals very rapid progression of the Omicron variant, with a prevalence of around 80 per cent, barely three weeks after the first confirmed case in Quebec," the INSPQ wrote.

"This means that eight out of 10 SARS-CoV-2 infections are attributed to the Omicron variant."

On Tuesday, Quebec topped 5,000 new daily cases for the first time in the pandemic, one of several records set in the last week.

As testing clinics were booked solid, and Quebecers began to rely more on at-home tests or simply had no access to testing, public health authorities also warned on Tuesday that the official daily case counts will become unreliable, as they'll be undercounts.

Before Omicron arrived, the province's previous daily record of new cases was just 2,880, the number recorded last Jan. 6, according to INSPQ's data. 

The institute also said that the province's overall strategy needs to change in terms of tracking the variant's spread, and that it's time to abandon trying hard to put extra efforts into containing known Omicron outbreaks.

"Considering the speed at which Omicron has established itself in other countries and elsewhere in Canada, it is no longer relevant or realistic to attempt to slow it down by systematic screening of positive cases and different [ways of] managing cases and contacts," INSPQ said bluntly.

"It is, however, useful to continue to document the speed of the variant's installation in Quebec in order to refine our projections and our models and thus better anticipate the real impact of this Omicron variant on the epidemiological situation, in particular on short-term hospitalizations and intensive care."

'A VERY PARTIAL PICTURE'

Labs across Quebec that are helping test viral DNA and track the different variants are still screening, as a priority, all positive cases by travellers returning from abroad.

But four "sentinel" labs in particular are routinely testing a portion of all of the positive cases from four hospital centres: two in Montreal, one in Quebec City, and one in the Laurentians, Laval and North Shore "cluster," the institute explained.

Put together, these routine screenings are helping paint a picture of how prevalent Omicron has become, INSPQ explained.

"This approach does not provide an accurate picture of the situation in each region, but allows us to understand the speed at which Omicron is replacing Delta," said the announcement.

"Considering the rate of replacement observed in the sentinel labs, there is every reason to believe that an equivalent rapid replacement [of the old variants] will occur across the province, within days."

It also warned that even these efforts create only a semi-accurate snapshot of what's happening. The only Omicron cases that are officially counted are those that are lab-confirmed, whether by DNA pre-screening or the most thorough kind of test, genome sequencing.

"Given the very rapid progression of the Omicron variant in Quebec, these results only present a very partial picture of the situation in Quebec," the INSPQ admitted.

It also reminded the public that a lot is still unknown about Omicron, which was only first documented in South Africa on Nov. 25, just four days before it showed up in Quebec.

"The Omicron variant is of concern because of its many mutations in its genome," the institute said, including mutations that make it more infections and also more adept at evading antibodies.

"There is still little data on the clinical severity of Omicron and how it is affected by vaccination or pre-existing immunity."