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 eleventh week of collection, which took place from March 24 to 29, 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.

→ Eleventh week of collection (March 24 to 29, 2022)

Highlights: 

• All four estimators are consistent and show an increase in case incidence relative to the previous week (statistically significant (p<0.1) except for the direct estimator of the incidence of cases without self-diagnosis).
• This increase in case incidence observed since the week ending March 17-22 increased in the week ending March 24-29.
• The estimates indicate disparities in the upward trend in incidence by region, with the increase appearing to be more pronounced in the Central and Northern regions of Quebec.
• The data show a slight increase in the number of people in isolation (not statistically significant) during the week ending March 24-29.
• Notwithstanding the direction of the trend from the previous week, the number of cases varies from 18,000 to 32,300 cases per day, depending on the estimation method used.

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),  Ingrid Peignier (CIRANO) and Alexandre Pud'Homme (Université de Montréal).