11 March 2022

Study to assess the incidence of COVID-19 in Quebec - Updated with data from the week of March 3 to 8, 2022

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 eighth week of collection, which took place from March 3 to 8, 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 several 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.

→ eighth week of collection (March 3 to 8, 2022)

Highlights:

Our estimators based on the indirect sampling method show a non-statistically significant increase in the number of new cases for this collection week compared to the previous week (5% to 12% increase depending on the estimator). The direct sampling estimates show discordant results, either an increase in case incidence (on the order of 2%) when self-tests are included or a 13% decrease for the estimate excluding self-tests. All of these differences, however, are not statistically significant.
In comparison, case count data based on PCR tests collected by INSPQ show a decrease of approximately 14% between week 7 and week 8 of collection.

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)