In a virtual press conference on July 30, Canada's Chief Public Health Officer Dr. Theresa Tam said data suggests that Canada is at the start of a fourth wave of COVID-19, mostly driven by the B.1.617.2 variant, known as the Delta variant.

Tam and Dr. Howard Njoo, Canada's deputy chief public health officer, presented new COVID-19 data modelling that forecasted what the COVID-19 pandemic in Canada could look like in early September.

"[The forecast] suggests that we are at the start of the Delta-driven fourth wave," Tam said.

However, she said the trajectory could change with rising numbers of fully vaccinated Canadians, as well as the "timing, pace and extent of reopening."

While some resurgence of the virus is expected as cities across Canada ease their public health restrictions, according to Tam, a rapid rise in new COVID-19 cases could mean that the country is reopening too quickly.

The updated modelling data showed that if Canadians increase their daily contacts with others by 25%, Canada could see at least 10,000 new cases daily by September.

Based on data from 11 provinces and territories, Tam said that from mid-December to July 12, only 0.5% of new cases were found in fully vaccinated Canadians. Unvaccinated Canadians made up 89.7% of new cases in the same time period.

In a July 29 tweet, Quebec Health Minister Christian Dubé said the province is in a "better position every day" to combat the Delta variant in Quebec.