Chief medical officer of health Dr. Deena Hinshaw said Monday that Alberta’s COVID-19 reproductive value dipped below one to 0.98.
“As of yesterday, the reproduction rate — or R value for the province — over the last seven days was 0.98,” Hinshaw said.
In the Edmonton zone it was 1.0, in the Calgary zone it was 0.92 and in the rest of Alberta it was 1.01.
“So what does that mean? This metric of R describes whether the rate of transmission over the past week increased or decreased or stayed the same,” Hinshaw said.
The R value explains how many people a positive case will infect. For example, if the R value is one, then one person will infect one other person, who infects one other person.
An R number of two means one person infects two others who go on to infect two others each. An R number of 0.5 means fewer people will become infected than the previous generation of cases.
“What last week’s values seem to indicate is that cases plateaued over the week,” she said.
“This is certainly better than an increase, but as the minister mentioned, a plateau is not enough, and a single week’s R value does not tell us about a trend.”
Alberta’s top doctor said the R value was encouraging but not enough. She stressed Albertans must not let their guard down and continue to practice good hygiene, stay home when sick and follow all public health measures.
“R is also not useful when looked at alone. We also need to look at our new daily case numbers, which remain high. What we need to achieve together is several weeks of an R value well below one, with a corresponding decrease in new case numbers.
“At present, even with this single week plateau, we are continuing to see growing hospitalizations and ICU admissions, which are straining our health system,” Hinshaw explained.
As of Monday, there were 716 Albertans in hospital with COVID-19; 136 of whom were in intensive care. Fifteen additional deaths from the coronavirus were reported Monday.
More than 20,000 tests were done, Hinshaw said, and Alberta identified 1,887 new cases. That means Alberta’s positivity rate is more than eight per cent.
At the end of April, Alberta’s R value was 1.4. By the end of May, it had decreased to 1.0, where it remained on June 19.
As of Nov. 22, the R value in Alberta was 1.12.
Biostatistician Ryan Imgrund, who works with Ottawa Public Health on that city’s R value, said his research shows that, as of Dec. 7, Alberta’s R value rose to 1.13.
Researchers with theCentre for Health Informatics, Cumming School of Medicine, University of Calgary have also been studying and sharing R value data for Alberta.
Alberta has since enacted even stronger restrictions, including banning all social gatherings and closing restaurants and bars for dine-in service, gyms, libraries and salons.
“We have been focused on getting the R value below one, which would mean that we would be seeing a decrease in the number of new daily cases every day,” Hinshaw said Monday.
“Having an R value provincially of 0.98 is encouraging — because it means that over the last week we plateaued, it means that, on average across the province, we did not have a growth of cases, but rather an even steady state.
“What we need to see is an R value well below one. An R value of 0.98 is not sufficient to bring our case counts down.”
She referenced the R value Jason Kenney previously spoke of — below 0.8 — but said it will need to be reached alongside fewer new daily cases.
“We are working on a proposal to bring forward to the COVID Cabinet Committee for the combination of both the R value and the number of new daily cases, because it has to be a combination of those metrics; it can’t be one or the other alone.
“That will tell us that we’ve been able to reduce the growth enough to protect our health care system,” Hinshaw said. “We continue to see significant pressure on our hospitals.
In terms of R value, “We didn’t grow last week, but what we need to do is actually shrink our cases. And that’s the challenge ahead of us,” Hinshaw added.
While the news of 29,000 doses of the Pfizer vaccine arriving in Alberta before the end of December presents cause for optimism, Hinshaw said it will be “some time” before the general public can be vaccinated.
“For the time being, we remain each other’s vaccine and best defense,” she said.
“We all must do our part to limit in-person interactions whenever possible.
“Together we must bend the curve and protect each other.”
With files from Julia Wong, Global NewsView link »