Ontario not particularly close to most thresholds for reopening considerations

Ontario's top doctor says he wants to see daily COVID-19 case numbers drop well below 1,000 before public health restrictions are rolled back in the province, but some experts say several other metrics should also be considered when deciding if lockdowns can ease.

Province not sharing benchmarks it wants to see in most categories for tracking virus spread

Chief Medical Officer of Health Dr. David Williams, left, says he wants to see Ontario under 1,000 daily cases of COVID-19 before reopening the province is considered. One expert says there are several other metrics the province needs to look at as well, and Ontario isn't particularly close to a reopening threshold in any of them. (Chris Young/The Canadian Press)

Ontario's top doctor says he wants to see daily COVID-19 case numbers drop well below 1,000 before public health restrictions are rolled back in the province, but some experts say several other metrics should also be considered when deciding if lockdowns can ease.

Provincial health officials are looking at a variety of factors when it comes to reopening, according to the Ministry of Health — but the province would not provide the specific benchmarks it needs to see in those categories when asked by CBC News.

Bio-statistician Ryan Imgrund says he believes the province isn't providing clear metrics to the public linked to its reopening plans because the government wants a "grey area" with some "wiggle room" so it can do whatever it deems is best.

"I'm certain they're not going to put clear metrics into play, and if they do, it's not going to matter because they won't follow them properly," Imgrund said.

When asked at a press conference Monday, Chief Medical Officer of Health Dr. David Williams said he "doesn't have a definite metric" for what needs to happen before Ontario can reopen.

"It certainly will be well below 1,000 [cases], but I think that is achievable," Williams said, adding officials would also like to see the number of patients in intensive care in the province drop under 150 as well.

As it stands, Ontario isn't near those marks, with another 2,073 cases of COVID-19 reported Tuesday. That's the fewest since March 24, but it comes just a day after 2,716 cases of the virus were reported on Monday.

Both of those figures were also reported with extremely low testing levels, with Public Health Ontario logging a high 8.5 per cent positivity rate Tuesday. Monday's positivity rate was even higher at 9.1 per cent, which is well above the 2.5 per cent mark listed in the red "control" zone of Ontario's pre-existing reopening framework.

The seven-day average of daily cases dropped to 2,914 Tuesday, which is the first time it has fallen below the 3,000 threshold in about five weeks.

The latest figures show 1,782 people with COVID-related illnesses in Ontario hospitals, with 802 in ICU — well above the 150 number Williams said he was hoping to see to ease restrictions.

Epidemiologist Dr. Tim Sly, a professor emeritus at Ryerson University in Toronto, told CBC News in an email that case counts are "useful as a day-to-day measure of how things are changing," but they underestimate the actual number of infections in the province by a decent margin.

Positivity rates are a better measure of how the virus is spreading, Sly said, but that number would be more precise with random sampling of the community through surveillance testing. When the criteria for having a test in the province is largely limited to people showing symptoms or recent contact with a confirmed case, then the likelihood of positive results is increased, he added.

"We need data that is consistent, valid, and reliable," Sly said.

Province won't share benchmarks

Ministry of Health spokesperson David Jensen told CBC News in an email that on top of case numbers, health officials are also examining things like per cent positivity, health system capacity and vaccination rates when making decisions about reopening.

He did not share any specific benchmarks that need to be hit in those categories before restrictions can ease.

"Our government will continue to act on the advice of public health experts, including the Chief Medical Officer of Health, who will review the science, data and trends along with collaborating with local medical officers of health and our team of expert health officials on when public health measures may be adjusted," he said.

Williams says he believes vaccines will help combat the third wave, but bio-statistician Ryan Imgrund says highly transmissible variants of the virus are slowing the impact they've had thus far. (Carlos Osorio/Reuters)

Case counts and hospitalization statistics are undoubtedly important, but Imgrund says there are other metrics he would also consider while making any decisions on reopening.

Chief among them is the number of weekly cases per 100,000 people in each region — a number that was listed as a consideration in the stages of the province's previous colour-coded reopening framework.

The grey, or most-restrictive lockdown portion of that framework should be triggered with 80 weekly cases per 100,000 people, Imgrund said. The latest figures from the province from May 1 to May 7 list Toronto at 203.1 cases per 100,000 people, and Peel Region at 318.3 cases per 100,000.

Those hot spots are extreme cases, but many Ontario regions are still above that 80 weekly cases per 100,000 mark. The province as a whole stood at 146 cases per 100,000 people in Ontario's latest reporting.

The red-control zone of the province's framework lists a weekly incidence rate of 40 cases per 100,000 people.

Province needs sustained drop in Rt

The other indicator that needs to be looked at in conjunction with weekly case rates per 100,000 is the R value (Rt), Imgrund said. That figure indicates the average number of people who will contract the virus from an infected person.

That number needs to be below one to see case rates dip. As of Monday, Ontario's value was 0.95.

But, Imgrund notes, it can take several weeks below that Rt of one threshold to see case rates truly start to drop off. Four weeks at a value below 0.8 would really make a dent in hospitalization rates, he said.

A sustained Rt of 0.89 would get Ontario to fewer than 1,000 cases a day by June 10, Imgrund said.

"It's evident that the Ontario [Rt] has been below 1.0 for more than a week now, and we need to maintain this trend," Sly added.

Williams also made sure Monday to point to rising vaccination rates as an advantage the province has when attempting to drive down the third wave.

"The thing is this time, unlike the first and second wave, we have vaccinations," he said, though vaccinations did start in very limited numbers amid the second wave.

Imgrund, however, said the increased rate of vaccinations is thus far just "levelling out" the impact of more transmissible strains of the virus, which is mitigating the gains they could have otherwise helped make. As of a week ago, the variant of concern first found in the United Kingdom was accounting for at least 94 per cent of all new cases.

"The third wave is predominantly due to this new variant," Sly said.

It will take weeks of more steady vaccinations and warmer weather allowing people to gather outside to really make a dent, Imgrund said.

Considering how the province's last stab at reopening went, Imgrund said his expectations are low that this time around will go smoothly.

"I'm not confident at all. I'm certain that they're not going to do this right if history is an indicator of performance."


Adam Carter


Adam Carter is a Newfoundlander who now calls Toronto home. You can follow him on Twitter @AdamCarterCBC or drop him an email at