Research Center for Zoonosis Control, Hokkaido University, Kita-ku, Sapporo-shi, Hokkaido 001-0020, Japan.
Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Yoshida-Nakaadachi-cho, Sakyo-ku, Kyoto, Japan; Hakubi Center for Advanced Research, Kyoto University Yoshidahonmachi, Sakyo-ku, Kyoto, Japan.
Int J Infect Dis. 2020 Jul;96:673-675. doi: 10.1016/j.ijid.2020.04.080. Epub 2020 May 8.
To estimate the ascertainment rate of novel coronavirus disease (COVID-19).
The epidemiological dataset of confirmed cases with COVID-19 in Japan as of February 28, 2020 was analyzed. A statistical model was constructed to describe the heterogeneity of the reporting rate by age and severity. We estimated the number of severe and non-severe cases, accounting for under-ascertainment.
The ascertainment rate of non-severe cases was estimated at 0.44 (95% confidence interval 0.37-0.50), indicating that the unbiased number of non-severe cases would be more than twice the reported count.
Severe cases are twice as likely to be diagnosed and reported when compared to other cases. Considering that reported cases are usually dominated by non-severe cases, the adjusted total number of cases is also approximately double the observed count. This finding is critical in interpreting the reported data, and it is advised that the mild case data for COVID-19 should always be interpreted as under-ascertained [Au?1].
估计新型冠状病毒病（COVID-19）的确诊率。
分析截至 2020 年 2 月 28 日日本确诊 COVID-19 病例的流行病学数据集。构建一个统计模型来描述按年龄和严重程度报告率的异质性。我们估计了严重和非严重病例的数量，这些数量考虑到了未确诊病例。
非严重病例的确诊率估计为 0.44（95%置信区间 0.37-0.50），表明非严重病例的无偏估计数将超过报告数的两倍。
与其他病例相比，严重病例被诊断和报告的可能性是其两倍。鉴于报告的病例通常以非严重病例为主，因此观察到的病例总数也大约是两倍。这一发现对解释报告数据至关重要，建议始终将 COVID-19 的轻症病例数据解读为未确诊病例[作者注 1]。
