PT  - JOURNAL ARTICLE
AU  - Abdollahi, Elaheh
AU  - Champredon, David
AU  - Langley, Joanne M.
AU  - Galvani, Alison P.
AU  - Moghadas, Seyed M.
TI  - Temporal estimates of case-fatality rate for COVID-19 outbreaks in Canada and the United States
AID  - 10.1503/cmaj.200711
DP  - 2020 Jan 01
TA  - Canadian Medical Association Journal
PG  - cmaj.200711
4099  - http://www.cmaj.ca/content/early/2020/05/22/cmaj.200711.short
4100  - http://www.cmaj.ca/content/early/2020/05/22/cmaj.200711.full
AB  - Background: Estimates of the casefatality rate (CFR) associated with coronavirus disease 2019 (COVID-19) vary widely in different population settings. We sought to estimate and compare the COVID-19 CFR in Canada and the United States while adjusting for 2 potential biases in crude CFR.Methods: We used the daily incidence of confirmed COVID-19 cases and deaths in Canada and the US from Jan. 31 to Apr. 22, 2020. We applied a statistical method to minimize bias in the crude CFR by accounting for the survival interval as the lag time between disease onset and death, while considering reporting rates of COVID-19 cases less than 50% (95% confidence interval 10%–50%).Results: Using data for confirmed cases in Canada, we estimated the crude CFR to be 4.9% on Apr. 22, 2020, and the adjusted CFR to be 5.5% (credible interval [CrI] 4.9%–6.4%). After we accounted for various reporting rates less than 50%, the adjusted CFR was estimated at 1.6% (CrI 0.7%–3.1%). The US crude CFR was estimated to be 5.4% on Apr. 20, 2020, with an adjusted CFR of 6.1% (CrI 5.4%–6.9%). With reporting rates of less than 50%, the adjusted CFR for the US was 1.78 (CrI 0.8%–3.6%).Interpretation: Our estimates suggest that, if the reporting rate is less than 50%, the adjusted CFR of COVID-19 in Canada is likely to be less than 2%. The CFR estimates for the US were higher than those for Canada, but the adjusted CFR still remained below 2%. Quantification of case reporting can provide a more accurate measure of the virulence and disease burden of severe acute respiratory syndrome coronavirus 2.