CIRANO has published an update of its exploratory study to estimate the incidence of COVID-19 cases in Quebec. This update integrates the data from the fifth week of collection, which took place from February 10 to 15, 2022, with a sample of 3000 respondents representative of the Quebec population and compares them to other collection weeks.
It should be noted that this study is spread over six consecutive weeks in order to monitor the evolution of the situation. The study uses both a direct sampling strategy and an indirect sampling estimation based on the network scale-up (NSS) method. Details of the methods are available in the CIRANO 2022s-03 working paper.
→ Update 5th week of collection (February 10 to 15, 2022)
Highlights:
The number of adults newly infected with COVID-19 based on PCR, rapid tests, or self-diagnosis over the past 7 days is 239,606 (34,229 cases per day) based on our direct sampling estimate. Excluding self-diagnosis, we instead obtain 163,799 cases over the past seven days, or an average of 23,400 cases per day.
By the network scale-up (NSS) method, we obtain estimates of 147,613 new cases (21,088 cases per day) using the Killworth et al. (1998) estimator and 137,434 new cases (or 19,633 cases per day), using the Habecker et al. (2015). estimator.
The data collected at time 5 seem to confirm that a plateau has been reached. The direct sampling estimates show a non-statistically significant increase in cases while the RPA-based estimators show a slight decrease in cases that is marginally statistically insignificant. In addition, data on the proportion of Quebec adults in isolation due to COVID-19, which showed a steady decline in all collection weeks from week 1 to week 4 (from 9% to 5.5%), appear to have stabilized since week 4, at around 5.5% of the adult population. We will have to wait until week 6 to see if there is a reversal of this trend.
This study is conducted by a team of researchers composed of David Boisclair (HEC Montréal), Roxane Borgès Da Silva (Université de Montréal and CIRANO), Vincent Boucher (Université Laval) Nathalie de Marcellis-Warin (Polytechnique Montréal and CIRANO), Pierre-Carl Michaud (HEC and CIRANO) and Ingrid Peignier (CIRANO)