余宏杰研究揭示H5N1禽流感流行病学特征

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导读：中国疾控中心余宏杰课题组通过系统收集长达18年的全球人感染H5N1禽流感个案数据，首次呈现了1997年至2015年全球人感染H5N1禽流感的流行病学特征，并且阐明了自2014年11月以来埃及上升疫情的流行病学特征及相关危险因素变化。相关成果日前在线发表于《柳叶刀—传染病》杂志。

自1997年香港特区发现了全球首例人感染高致病性禽流感H5N1病例以来，近10年间H5N1禽流感病毒在全球蔓延，不断引起人类发病，并且具有较高的病死率。研究推测，该病毒可通过基因重配或突变演变为引起人类流感大流行的病毒，因此成为全球关注的焦点。

余宏杰课题组系统整理了1997年5月至2015年4月全球907例人感染H5N1禽流感病例个案及其可能暴露因素的数据，并围绕全球人感染H5N1高致病性禽流感个案及其流行病学特点开展了系统研究。

研究发现，人禽流感H5N1疫情主要发生在东亚、东南亚和北非国家，并在2003年至2008年逐渐从东亚扩散到东南亚、西亚和非洲。全球人禽流感H5N1总病死率为53.5%，但各地区有所差异。从全球范围看，67.2%的病例发生在12月至次年3月，而且2015年报告了最多的病例。病例的年龄中位数为19岁，同时80%的病例在35岁以下，但埃及死亡病例的年龄中位数高于东亚和东南亚死亡病例。

研究还表明，人感染H5N1禽流感病毒clade 1、2.1和2.3的病死率高于clade 0和2.2。尽管2014年11月至2015年4月埃及的人禽流感H5N1疫情有所上升，但与之前相比，患者病死率、禽类暴露史、发病至住院的时间等没有显著性差异。

相关专家表示，该研究为下一步的疫苗和抗病毒药物研发、疫情驱动因素的研究和防控提供了科学证据。

题目：Global epidemiology of avian influenza A H5N1 virus infection in humans, 1997–2015: a systematic review of individual case data

Summary

Avian influenza A H5N1 viruses have caused many, typically severe, human infections since the first human case was reported in 1997. However, no comprehensive epidemiological analysis of global human cases of H5N1 from 1997 to 2015 exists. Moreover, few studies have examined in detail the changing epidemiology of human H5N1 cases in Egypt, especially given the outbreaks since November, 2014, which have the highest number of cases ever reported worldwide in a similar period. Data on individual patients were collated from different sources using a systematic approach to describe the global epidemiology of 907 human H5N1 cases between May, 1997, and April, 2015. The number of affected countries rose between 2003 and 2008, with expansion from east and southeast Asia, then to west Asia and Africa. Most cases (67·2%) occurred from December to March, and the overall case-fatality risk was 483 (53·5%) of 903 cases which varied across geographical regions. Although the incidence in Egypt has increased dramatically since November, 2014, compared with the cases beforehand, there were no significant differences in the fatality risk, history of exposure to poultry, history of patient contact, and time from onset to hospital admission in the recent cases.

来源：中国科学报

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