Why comparing COVID-19 hospitalization numbers between provinces isn't apple to apples

The number of COVID-19 patients in hospital and intensive care has been on the rise in many provinces lately, but comparing these numbers isn't exactly an apples-to-apples comparison. Not all provinces count patients the same way.

The key difference is whether the official numbers include patients who remain in hospital or intensive care units (ICU) but are no longer considered infectious.

In Alberta, these patients are included in the data that the province publishes daily.

"We report them as long as they are hospitalized with COVID-19 as a contributing cause, regardless of whether they are infectious," said Alberta Health spokesperson Tom McMillan.

Health officials in Quebec and Saskatchewan say they count patients in the same way.

But British Columbia does it differently.

"Patients in ICU in B.C. with COVID-19 who are no longer infectious are not in the ICU totals that are reported daily," Justine Ma with B.C.'s Provincial Health Services Authority said in an email.

It's not entirely clear if the same applies to B.C. patients who are hospitalized outside of ICUs. Asked for clarification on that, Ma did not answer.

Manitoba, meanwhile, reports both numbers.

As of Wednesday's daily update, the province said 61 patients were in hospital with active COVID-19, as well as 79 more patients who are no longer infectious but continue to require care, for a total of 140 hospitalizations.

This included 12 patients in ICU who remain infectious and 18 who are no longer infectious, for a total of 30.

Ontario recently started making this distinction when it comes to ICU patients as well — but not for the total number of patients in hospital.

Ontario changes ICU reporting method

As of last week, the Ontario government's official data started differentiating between the "number of patients in ICU, testing positive for COVID-19" (i.e. those who are still considered infectious) and the "number of patients in ICU, testing negative for COVID-19."

As of Wednesday, the data showed 504 total COVID-19 patients in Ontario ICUs, 476 of whom were still testing positive and considered infectious.

The Ontario government had come under some criticism recently for reporting the lower number only, while Critical Care Services Ontario, a separate government agency, reported the higher number.

Ontario's public-facing COVID-19 data website now shows both numbers: the higher number in the daily "overview of cases" and the lower numbers in a chart of past hospitalization data.

It's not clear how New Brunswick reports its data, which showed 18 people in hospital on Wednesday including 12 in intensive care. CBC News has asked the province's health ministry for clarification but has yet to receive a reply.

In the rest of Atlantic Canada, meanwhile, hospitalizations for COVID-19 remain rare.

As of Wednesday, Nova Scotia was reporting one patient in hospital (outside of ICU) while Prince Edward Island and Newfoundland and Labrador each reported zero hospitalized patients.