A key signal will be the “R number,” or reproduction number, which is a way of rating a disease’s ability to spread. From a public health perspective, it can help identify whether or not that spread is manageable.
Nationally, that number is now “hovering above one,” said Dr. Theresa Tam, Canada’s chief public health officer, at a news conference Tuesday.
“That’s not a good sign,” she noted. “We do not want that to happen. So that needs to be monitored very carefully.”
Canada’s daily case numbers have increased recently. According to Tam, the average daily number of people testing positive over the last week has increased 25 per cent over the previous week.
Some provinces have it worse than others. British Columbia has seen a spike in cases, months after seeing daily counts drop to single digits. Ontario and Quebec are also seeing a rise in daily reported cases.
The tallies come on the heels of back to school for many provinces.
Tam and deputy chief public health officer Dr. Howard Njoo said the R number needs to be kept “below one for a long period of time” to avoid a “rapid resurgence.”
In other words, if one person, on average, infects one other person, the R number is one. If one person, on average, infects two, the R number is two. An R of two is catastrophic. If the cycle continues, so, too, does the spread of the virus.
Daily case numbers from the provinces and the infection rate will also be important indicators of a worsening situation, Tam added.
“The next two weeks is not just a reflection of schools or colleges, but also, of course, this last long weekend. So if there have been any other gatherings that have potential to spark any new trains of transmission,” Tam said.
“We’re looking for whether we are going to keep these numbers at a relatively low level that public health can manage, while still balancing societies being able to be open.”
Schools have been a contentious issue so far in Canada. While there are a host of COVID-19 protocols that vary province to-province, clusters of cases at schools in Quebec and Ontario have ignited criticism over back-to-school plans and heightened fears of transmission risks.
Both Njoo and Tam called the cases at schools “concerning,” but said, at this point, the finger can’t be pointed squarely at schools.
“I want to underscore that when cases happen in places like schools, it is a reflection of what is happening in the community,” Njoo said.
In Quebec, an outbreak of the virus linked to a karaoke bar in Quebec City has generated 40 cases of COVID-19 alone. Those cases, according to local health officials, have led to 10 more infections among family members — including three students who returned to school.
“For schools, what we’re seeing now, if a case was caught, that means our public health system is working well at capturing it,” he said. “We need to know if there are two or three cases that are linked.”
Tam reiterated her warning of compliance with health protocols and so-called “super-spreading” events.
“What we don’t want is this virus getting into a setting where there is a high degree of transmission, sometimes called super-spreading events. Those are crowded, enclosed places where people are gathering where they’re not observing public health measures or where we have to help them adjust their protocols to better manage,” she said.
“The most difficult part is private functions, family gatherings, where we need to make sure we support persons in this country to know what to do to minimize the risk.”
As of Sept. 7, there were 132,142 cases of COVID-19 in Canada — 116,459 of those have recovered. More than 9,000 Canadians have died.
— with files from the Canadian PressView link »