Federal modelling suggests 'very intense' Omicron surge within weeks

New modelling released today by the Public Health Agency of Canada (PHAC) suggests the highly transmissible Omicron variant will push hospital admissions to "extremely high levels" in the coming weeks as case counts reach levels never before seen in this country.

While there is a lot of uncertainty about how many new infections are being reported each day due to ongoing COVID-19 testing constraints, PHAC said the current test positivity rate suggests the variant is running rampant and there will be "several weeks of very intense activity expected to come."

Nationally, the positivity rate is a stunning 28 per cent. That means more than one in four tests for the virus are coming back positive — nearly five times higher than the rate at any other point in the pandemic.

That sky-high number may be skewed by testing limitations, now that some provinces and territories are restricting testing access to groups most vulnerable to COVID-19.

To maintain the health care system and the "critical functions of society," PHAC is urging Canadians to limit in-person contacts, get their booster shots and wear good quality, snug-fitting face masks to help stop transmission of a variant that is ripping through communities nationwide.

While PHAC said Omicron is likely less severe than past variants — the risk of hospitalization is lower than with the Delta variant, for example — the sheer number of new infections means more people will be susceptible to severe outcomes, including hospitalization and death.

The "enormous volume of cases" — the modelling suggests there could be as many as 150,000 new infections a day sometime this month — is driving an increase in severe illness trends nationally, PHAC said. New hospital admissions could surge to somewhere between 2,000 and 4,000 each day, well above historic highs.

Since December, the number of people with COVID-19 being treated in hospitals has more than quadrupled to an average of over 6,779 daily, while the number in critical care has doubled to an average of over 884 daily. Meanwhile, 82 deaths are being reported each day.

While the high volume of cases is driving an increase in hospitalization rates across all age groups, the number of hospital and ICU admissions is still highest among adults 80 years of age or older.

Infection rates could be stabilizing in Quebec, Ontario 

People over 80 report hospitalization rates eight to 10 times higher than younger cohorts. But unlike previous pandemic waves, the Omicron wave also has seen a small but notable uptick in hospitalizations among young children.

There are early indications that the rate of new infections may be stabilizing in Ontario and Quebec. "It is quite possible that in the next few days we'll see a peak in the cases," said Dr. Theresa Tam, Canada's chief public health officer.

WATCH | Dr. Theresa Tam on current COVID modelling:

Chief public health officer says it's 'possible' Canada will see COVID cases peak in coming days

3 years ago

Duration 1:12

Theresa Tam, the chief public health officer of Canada, says the COVID-19 surge should peak in the coming days but we will know more next week.

But the number of new hospital admissions will remain high for the foreseeable future because there's a lag time between infection and severe outcomes.

"We could be like other countries — seeing a sharp, sharp increase and then it coming down fairly fast. But we all just want to be cautious about pronouncing on that before we see more information," Tam said.

Omicron has wreaked havoc because it is able to evade prior immunity from past infections and vaccination. PHAC said two doses of an mRNA vaccine are not very effective against infection and symptomatic disease; it described vaccine efficacy against an Omicron infection as "low to very low."

However, people with two doses of a vaccine are less likely to be admitted to hospital. PHAC data suggest unvaccinated people are 19 times more likely to be hospitalized with COVID-19 than fully vaccinated people.

"These trends clearly show that being vaccinated with two or more doses is highly protective. As booster doses continue to expand, being up-to-date with COVID-19 vaccines is expected to preserve this protection advantage," Tam said.

To prevent further strain on hospitals, PHAC is urging vaccine holdouts to finally get a dose. More than 6.5 million eligible Canadians are not yet fully vaccinated. Vaccine coverage among people aged 5 to 11 remains stubbornly low, with just 48 per cent of kids in this age group having had at least one dose.

Tam said Pfizer's promising antiviral, Paxlovid, may be a useful tool in the next phase of this pandemic fight — and future federal modelling on hospitalizations and deaths may have to be updated if and when this self-administered treatment is widely available for high-risk patients.

Clinical trial results suggest Paxlovid reduced the risk of hospitalization or death by an impressive 89 per cent compared to a placebo in non-hospitalized high-risk adults with COVID-19.

Health Canada is reviewing the product now, but a post-approval delivery schedule remains uncertain.

"There's a global supply constraint and it may not be in widespread use for a while. What we're trying to do at PHAC is convene experts to help provide some considerations as to how the initial supplies could be prioritized, much as we did with the initial batch of vaccines. That work is underway," Tam said.