Estimates of COVID-19 case-fatality risk from individual-level data Simona Bignami-Van Assche*, PhD (Université de Montréal) Daniela Ghio, PhD (Joint Research Center European Commission) Ari Van Assche, PhD (HEC Montréal) ABSTRACT When calculated from aggregate data on confirmed cases and deaths, the case-fatality risk (CFR) is a simple ratio between the former and the latter, which is prone to numerous biases. With individual-level data, the CFR can be estimated as a true measure of risk as the proportion of incidence for the disease. We present the first estimates of the CFR for COVID-19 by age and sex based on event history modelling of the risk of dying among confirmed positive individuals in the Canadian province of Ontario, which maintains one of the few individual-level datasets on COVID-19 in the world. * Corresponding author: Simona Bignami-Van Assche, PhD, Université de Montréal, Département de démographie, 3150 rue Jean Brillant, Montréal, Québec, H3C 3J7, Canada (simona.bignami@umontreal.ca). All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 22, 2020. . https://doi.org/10.1101/2020.04.16.20067751 doi: medRxiv preprint