Agent-Based Modelling Laboratory (Abdollahi, Moghadas), York University, Toronto, Ont.; Department of Pathology and Laboratory Medicine (Champredon), Western University, London, Ont.; Canadian Center for Vaccinology (Langley), Dalhousie University, IWK Health Centre and Nova Scotia Health Authority (Langley), Halifax, NS; Center for Infectious Disease Modeling and Analysis ( Galvani), Yale School of Public Health, New Haven, Conn.
CMAJ. 2020 Jun 22;192(25):E666-E670. doi: 10.1503/cmaj.200711. Epub 2020 May 22.
Estimates of the case-fatality 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.
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%).
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%).
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.
在不同的人群环境中，与 2019 年冠状病毒病（COVID-19）相关的病死率（CFR）的估计值差异很大。我们试图在调整 2 种粗 CFR 潜在偏倚的情况下，估计并比较加拿大和美国的 COVID-19 CFR。
我们使用了 2020 年 1 月 31 日至 4 月 22 日加拿大和美国 COVID-19 确诊病例和死亡的每日发病率。我们应用了一种统计方法，通过将生存间隔（从发病到死亡的滞后时间）纳入疾病暴发的粗 CFR 中，同时考虑到 COVID-19 病例报告率低于 50%（95%置信区间 10%-50%），来最小化粗 CFR 的偏倚。
使用加拿大确诊病例数据，我们估计 2020 年 4 月 22 日的粗 CFR 为 4.9%，调整后的 CFR 为 5.5%（置信区间[CrI] 4.9%-6.4%）。在考虑到各种报告率低于 50%的情况后，调整后的 CFR 估计为 1.6%（CrI 0.7%-3.1%）。美国 2020 年 4 月 20 日的粗 CFR 估计为 5.4%，调整后的 CFR 为 6.1%（CrI 5.4%-6.9%）。在报告率低于 50%的情况下，美国调整后的 CFR 为 1.78（CrI 0.8%-3.6%）。
我们的估计表明，如果报告率低于 50%，加拿大 COVID-19 的调整后 CFR 可能低于 2%。美国的 CFR 估计值高于加拿大，但调整后的 CFR 仍低于 2%。对病例报告的量化可以提供对严重急性呼吸综合征冠状病毒 2 的毒力和疾病负担的更准确衡量。
