MONTREAL — Health officials reported Wednesday that nearly three million Quebecers, including more than a third of all children, are believed to have been infected by COVID-19 since the beginning of the Omicron wave.

Dr. Luc Boileau, the province's interim public health director, provided the revised figure at a news conference, adding one million cases to the two million estimated just two weeks ago.

Boileau said the calculations are based on modelling using hospitalizations that allow authorities to infer the actual number of cases, since PCR testing is now limited to certain high-risk groups. They also looked at a serological study conducted by researchers at Sainte-Justine children's hospital in Montreal that estimates that 35 to 40 per cent of Quebec children had COVID-19 as the Omicron variant spread.

"The Omicron wave was without doubt stronger than we thought," Boileau told reporters, saying authorities are taking a calculated risk by allowing school-aged students to remove their masks in the classroom when they return from their break week on March 7.

Marie-France Raynault, a medical adviser to the Health Department, said allowing children to remove their masks while seated in class presents more benefits than risks, particularly for socialization and for vulnerable children with trouble learning. 

"A lot of children have been infected or have antibodies because they were vaccinated," Raynault said. While the risk from COVID is low for children, she said, vulnerable children face other risks, "and they've suffered a lot since the beginning of the pandemic." She noted masks will still be required in common areas and on school transportation. Teachers will also be asked to keep their masks on.

Boileau said while the March break week was blamed for accelerating spread of the virus during the first wave of COVID-19 in 2020, the situation is different now because of vaccination and the number of children infected by Omicron.

Boileau said the province's COVID-19 indicators were encouraging as authorities prepare to lift most measures by March 14.

On Wednesday, health authorities reported 17 COVID-19-linked deaths and listed 1,672 people in hospital with the disease, a drop of 70 patients. There were 102 patients listed in intensive care, a decline of five patients. Authorities said 12,669 doses of vaccine had been administered in the previous 24 hours.

Earlier in the day, a Quebec health research institute said that projections for the next two weeks show the number of people in Quebec hospitals with COVID-19 should drop to 1,200, with the number of intensive care patients by that time at about 50.

The Institut national d'excellence en santé et en services sociaux said in a statement that it expected the number of new hospitalizations to reach around 50 per day during that same two-week period.

In Montreal, public health director Dr. Mylène Drouin told a news conference that an estimated one million people in the city contracted COVID-19 during the fifth wave of the pandemic, with at least one-third of the population infected.

But she said the peak of the Omicron wave has passed. "We have seen in the last five weeks that all our indicators are decreasing," Drouin said.

"We want to make sure that we still stay vigilant because we could see other variants coming in, and the virus is still circulating at a high level in Montreal," she added.

Drouin said that nearly two years after the first COVID-19 case was confirmed in the city — Feb. 27, 2020 — it is time to move to a "transition phase" where people will have to make it a habit to get tested when they have symptoms and isolate when they test positive with a rapid test.

Also Wednesday, Quebec's workers' health and safety commission announced that wearing a mask at work continuously won't be required if two-metre distancing or a barrier is in place. The change comes as the province is set to end its remote working requirement on Feb. 28.

This report by The Canadian Press was first published Feb. 23, 2022.

Sidhartha Banerjee, The Canadian Press