Verguet Stéphane, Jones Edward O, Johri Mira, Morris Shaun K, Suraweera Wilson, Gauvreau Cindy L, Jha Prabhat, Jit Mark
Department of Global Health and Population, Harvard T.H. Chan School of Public Health, 665 Huntington Avenue, Boston, MA, USA.
Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.
BMC Med. 2017 Aug 10;15(1):151. doi: 10.1186/s12916-017-0908-3.
Decreasing trends in measles mortality have been reported in recent years. However, such estimates of measles mortality have depended heavily on assumed regional measles case fatality risks (CFRs) and made little use of mortality data from low- and middle-income countries in general and India, the country with the highest measles burden globally, in particular.
We constructed a dynamic model of measles transmission in India with parameters that were empirically inferred using spectral analysis from a time series of measles mortality extracted from the Million Death Study, an ongoing longitudinal study recording deaths across 2.4 million Indian households and attributing causes of death using verbal autopsy. The model was then used to estimate the measles CFR, the number of measles deaths, and the impact of vaccination in 2000-2015 among under-five children in India and in the states of Bihar and Uttar Pradesh (UP), two states with large populations and the highest numbers of measles deaths in India.
We obtained the following estimated CFRs among under-five children for the year 2005: 0.63% (95% confidence interval (CI): 0.40-1.00%) for India as a whole, 0.62% (0.38-1.00%) for Bihar, and 1.19% (0.80-1.75%) for UP. During 2000-2015, we estimated that 607,000 (95% CI: 383,000-958,000) under-five deaths attributed to measles occurred in India as a whole. If no routine vaccination or supplemental immunization activities had occurred from 2000 to 2015, an additional 1.6 (1.0-2.6) million deaths for under-five children would have occurred across India.
We developed a data- and model-driven estimation of the historical measles dynamics, CFR, and vaccination impact in India, extracting the periodicity of epidemics using spectral and coherence analysis, which allowed us to infer key parameters driving measles transmission dynamics and mortality.
近年来有报道称麻疹死亡率呈下降趋势。然而，此类麻疹死亡率估计在很大程度上依赖于假定的区域麻疹病例致死风险（CFR），总体上很少利用低收入和中等收入国家的死亡率数据，尤其是未充分利用全球麻疹负担最重的印度的死亡率数据。
我们构建了印度麻疹传播动态模型，其参数通过频谱分析从《百万死亡研究》提取的麻疹死亡率时间序列中进行实证推断，该研究是一项正在进行的纵向研究，记录了240万印度家庭的死亡情况，并通过口头尸检确定死因。然后，该模型用于估计2000 - 2015年印度以及比哈尔邦和北方邦（UP）五岁以下儿童的麻疹CFR、麻疹死亡人数以及疫苗接种的影响，这两个邦人口众多且印度麻疹死亡人数最多。
我们得出2005年五岁以下儿童的估计CFR如下：印度整体为0.63%（95%置信区间（CI）：0.40 - 1.00%），比哈尔邦为0.62%（0.38 - 1.00%），北方邦为1.19%（0.80 - 1.75%）。在2000 - 2015年期间，我们估计印度整体有60.7万（95% CI：38.3万 - 95.8万）五岁以下儿童死于麻疹。如果2000年至2015年未开展常规疫苗接种或补充免疫活动，印度五岁以下儿童将额外增加160万（100万 - 260万）死亡。
我们通过数据和模型驱动对印度历史上的麻疹动态、CFR和疫苗接种影响进行了估计，利用频谱和相干分析提取了疫情的周期性，这使我们能够推断驱动麻疹传播动态和死亡率的关键参数。
