A new study by the Center interuniversitaire de recherche en analyze des organizations (CIRANO) estimates that 33,000 to 58,000 new cases of COVID-19 have been recorded each day in the province in the past few days, five to eight times more than the 6,500 to 7,000 cases reported by Quebec in its daily reports.
Posted at 5:00 a.m.
Since January 4, Quebec no longer has reliable data on the number of cases of COVID-19 in the province, because PCR screening tests are no longer accessible to the entire population. Authorities are now using hospitalization data to determine whether the epidemiological situation is improving or deteriorating.
But researchers Roxane Borgès Da Silva, David Boisclair, Vincent Boucher, Nathalie de Marcellis-Warin, Pierre-Carl Michaud and Ingrid Peignier, from CIRANO, decided to measure the incidence of COVID-19 in Quebec by estimating “the number of adults who have received a positive test result, rapid or PCR, or who have self-diagnosed as having had COVID-19 on the basis of symptoms”.
“Representative Sampling”
In all, 3,000 people forming a “representative sample of the population of Quebec” were surveyed by internet from January 13 to 18 and were questioned as to whether they had had COVID-19 in the last seven days. They were also asked the following question: “How many people do you know who have tested positive for COVID-19 in the last seven days (including today)? to refine the estimates using an indirect sampling technique.
According to the study, during a seven-day period ending between January 13 and 18, 231,967 to 261,863 adults tested positive for a PCR or rapid test, or 33,138 to 37,409 cases. per day. “Carried out in the short term, in view of the rise in cases and to make up for the lack of an estimate of the number of cases in Quebec, this study shows that the official results of PCR tests underestimate by a multiple of five the number of results positive in Quebec over the period”, is it indicated in the study, published this Friday.
If we add the people who reported a positive self-diagnosis, 407,430 probable cases of COVID-19 were recorded (58,144 per day), eight times more than the daily toll.
A leading indicator
In their study, the researchers explain that it is essential to know the number of cases of COVID-19 in Quebec, in particular because “the number of new cases is a leading indicator of future hospitalizations”. “The number of cases allows us to make projections on future hospitalizations. Which is very important, especially in a context where our healthcare system is reaching its limits,” notes Roxane Borgès Da Silva. Knowing the number of cases also makes it possible to assess “the level of severity of the Omicron variant”. The study will also be repeated four times in the coming weeks.
It will be interesting to see the effect of the opening of schools on cases.
Roxane Borgès Da Silva, researcher at CIRANO
For the moment, these data do not confirm whether the province is indeed reaching a plateau in the number of new cases of COVID-19, explains the researcher. “It is by having the data for the next few weeks that we can assess the trend,” she said.