The Time Required to Estimate the Case Fatality Ratio of Influenza Using Only the Tip of an Iceberg: Joint Estimation of the Virulence and the Transmission Potential
The Time Required to Estimate the Case Fatality Ratio of Influenza Using Only the Tip of an Iceberg: Joint Estimation of the Virulence and the Transmission Potential
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DOI：
10.1155/2012/978901
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发表时间：
2012-01-01
影响因子：
--
通讯作者：
Nishiura, Hiroshi
中科院分区：
文献类型：
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作者：
Ejima, Keisuke;Omori, Ryosuke;Nishiura, Hiroshi
估计大流行早期阶段新型流感病毒株的病死率（CFR）是快速研究响应中需要进行的关键流行病学任务之一。过去严重急性呼吸系统综合症 (SARS) 和甲型流感 (H1N1-2009) 流行期间的经验对实时估算 CFR 提出了一些技术挑战。本研究旨在开发一种简单的方法来根据现成的数据集（即确诊病例和死亡人数）来估计病死率，同时解决一些已知的技术问题。为了评估所提出方法的可靠性和有效性，我们通过蒙特卡罗模拟检查了指定的 CFR 包含在 95% 置信区间内以及估计的 CFR 低于预先指定的截止值所需的最短时间长度。总体而言，传播潜力越小，将估计 CFR 与截止值进行比较所需的时间就越长。如果政策制定和公共卫生应对措施必须基于从提议的方法和现成数据得出的病死率估计值，那么应该注意的是，成功的估计可能需要几个月以上的时间。
Estimating the case fatality ratio (CFR) of a novel strain of influenza virus during the early stage of the pandemic is one of key epidemiological tasks to be conducted as rapid research response. Past experience during the epidemics of severe acute respiratory syndrome (SARS) and influenza A (H1N1-2009) posed several technical challenges in estimating the CFR in real time. The present study aimed to develop a simple method to estimate the CFR based on readily available datasets, that is, confirmed cases and deaths, while addressing some of the known technical issues. To assess the reliability and validity of the proposed method, we examined the minimum length of time required for the assigned CFR to be included within the 95% confidence intervals and for the estimated CFR to be below a prespecified cut-off value by means of Monte Carlo simulations. Overall, the smaller the transmission potential was, the longer it took to compare the estimated CFR against the cut-off value. If policymaking and public health response have to be made based on the CFR estimate derived from the proposed method and readily available data, it should be noted that the successful estimation may take longer than a few months.