Department of Mathematical Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Int J Biol Sci. 2012;8(5):620-9. doi: 10.7150/ijbs.4329. Epub 2012 Apr 23.
As part of measles elimination effort, evaluation of the vaccination program and real-time assessment of the epidemic dynamics constitute two important tasks to improve and strengthen the control. The present study aimed to develop an epidemiological modeling method which can be applied to estimating the vaccine efficacy at an individual level while conducting the timely investigation of the epidemic. The multivariate renewal process model was employed to describe the temporal evolution of infection by vaccination history, jointly estimating the time-dependent reproduction number and the vaccine efficacy. Analyzing the enhanced surveillance data of measles in Aichi prefecture, Japan from 2007-08, the vaccine efficacy was estimated at 96.7% (95% confidence interval: 95.8, 97.4). Using an age structured model, the vaccine efficacy among those aged from 5-19 years was shown to be smaller than that among those from 0-4 years. The age-dependent vaccine efficacy estimate informs the age-groups to be targeted for revaccination. Because the estimation method can rest on readily available epidemiological data, the proposed model has a potential to be integrated with routine surveillance.
作为消除麻疹工作的一部分，评估疫苗接种计划和实时评估疫情动态是改善和加强控制的两项重要任务。本研究旨在开发一种流行病学建模方法，该方法可用于在及时进行疫情调查的同时，估算个体水平的疫苗效力。采用多元更新过程模型来描述接种史引起的感染随时间的演变，联合估计时变繁殖数和疫苗效力。分析了来自日本爱知县的 2007-08 年麻疹强化监测数据，估计疫苗效力为 96.7%（95%置信区间：95.8，97.4）。使用年龄结构模型，发现 5-19 岁年龄组的疫苗效力小于 0-4 岁年龄组。年龄相关的疫苗效力估计为确定需要加强免疫的年龄组提供了信息。由于估计方法可以基于现成的流行病学数据，因此所提出的模型有可能与常规监测相结合。
