Kobayashi Tetsuro, Jung Sung-Mok, Linton Natalie M, Kinoshita Ryo, Hayashi Katsuma, Miyama Takeshi, Anzai Asami, Yang Yichi, Yuan Baoyin, Akhmetzhanov Andrei R, Suzuki Ayako, Nishiura Hiroshi
Graduate School of Medicine, Hokkaido University, Kita 15 Jo Nishi 7 Chome, Kita-ku, Sapporo-shi, Hokkaido 060-8638, Japan.
Osaka Institute of Public Health, Nakamichi 1-3-69, Higashinari, Osaka 537-0025, Japan.
J Clin Med. 2020 Feb 21;9(2):580. doi: 10.3390/jcm9020580.
To understand the severity of infection for a given disease, it is common epidemiological practice to estimate the case fatality risk, defined as the risk of death among cases. However, there are three technical obstacles that should be addressed to appropriately measure this risk. First, division of the cumulative number of deaths by that of cases tends to underestimate the actual risk because deaths that will occur have not yet observed, and so the delay in time from illness onset to death must be addressed. Second, the observed dataset of reported cases represents only a proportion of all infected individuals and there can be a substantial number of asymptomatic and mildly infected individuals who are never diagnosed. Third, ascertainment bias and risk of death among all those infected would be smaller when estimated using shorter virus detection windows and less sensitive diagnostic laboratory tests. In the ongoing COVID-19 epidemic, health authorities must cope with the uncertainty in the risk of death from COVID-19, and high-risk individuals should be identified using approaches that can address the abovementioned three problems. Although COVID-19 involves mostly mild infections among the majority of the general population, the risk of death among young adults is higher than that of seasonal influenza, and elderly with underlying comorbidities require additional care.
为了解特定疾病的感染严重程度，估计病例死亡率是常见的流行病学做法，病例死亡率定义为病例中的死亡风险。然而，要适当衡量这一风险，有三个技术障碍需要解决。首先，用死亡累计数除以病例累计数往往会低估实际风险，因为尚未观察到将会发生的死亡情况，因此必须考虑从发病到死亡的时间延迟。其次，报告病例的观察数据集仅代表所有受感染个体的一部分，可能有大量无症状和轻度感染个体从未被诊断出来。第三，使用较短的病毒检测窗口和不太敏感的诊断实验室检测方法进行估计时，所有感染者中的确诊偏倚和死亡风险会较小。在当前的新冠疫情中，卫生当局必须应对新冠死亡风险的不确定性，应采用能够解决上述三个问题的方法来识别高危个体。尽管新冠在大多数普通人群中主要表现为轻度感染，但年轻人的死亡风险高于季节性流感，有基础合并症的老年人需要额外护理。
