COVID-19 testing capacity is overwhelmed. Here's how Canadians can still measure risk

Canada has lost sight of the true size of its pandemic, with the number of people infected with COVID-19 now a mystery, as the highly infectious Omicron variant overwhelms testing capacity across the country.

Omicron is causing a never-before-seen surge in COVID-19 that has prompted provinces to reinstate curfews and gathering restrictions, shutter bars and restaurants and move schooling back online in a desperate attempt to mitigate the impact on hospitals.

Yet those case levels are about to drop off a cliff — not because of the flood of new public health restrictions across the country that haven't yet taken effect, but because health officials have simply stopped testing the majority of Canadians for COVID-19. 

So how do we track the impact Omicron is having across Canada? And how will we know whether public health restrictions are working if officials aren't collecting accurate data?

"Omicron is moving so quickly that it has become pretty much impossible to pin down the full extent of spread in real time," said Dr. David Naylor, who led the federal inquiry into the 2003 SARS epidemic and co-chairs the federal government's COVID-19 immunity task force.

"PCR testing capacity is overwhelmed," Naylor said. "Rapid antigen tests [RAT] are inconsistently available. Those with positive RAT results often have no way to register them let alone confirm them."

Public health experts and epidemiologists agree COVID-19 hospitalizations and intensive care unit (ICU) admissions have replaced case numbers as some of the most important metrics for understanding Omicron's impact on the health-care system and severity of illness it causes. 

"It was always what was going to happen," said Dr. Allison McGeer, a medical microbiologist and infectious disease specialist at Toronto's Mount Sinai Hospital who worked on the front lines of the SARS epidemic in 2003. 

"We were always going to switch from cases to hospitalizations as a measure of how well we were doing." 

But even those numbers can be skewed with Omicron. Data shows while the variant is highly contagious, vaccines still offer protection against serious illness and those infected are less likely to wind up in hospital than people with the Delta variant. 

That may lead to a shift in focus to hospitalizations, because the biggest concern with Omicron is that it's spreading like wildfire and leaving more people exposed to potentially serious outcomes that could strain the health-care system. 

A recent report from Public Health Ontario found that while the risk of hospitalization and death was 54 per cent lower for Omicron than Delta — the fact that it is infecting so many more people may actually lead to an overall increase in hospitalizations. 

WATCH | Canadian hospitals brace for rising COVID-19 admissions, staff shortages:

Omicron is also better at dodging immune protection from vaccines and prior infection than previous variants, dealing a massive blow to the effectiveness of COVID-19 vaccines against infection — but not necessarily against severe illness.