[Analysis on influencing factors for acute gastroenteritis outbreaks caused by norovirus in Beijing, 2014-2018].

Objective: To analyze the influencing factors of acute gastroenteritis outbreaks caused by norovirus in Beijing from 2014 to 2018. Methods: Data of acute gastroenteritis events caused by norovirus in Beijing from April 2014 to March 2018 were collected. Unconditional logistic regression model was conducted to identify the risk factors of the outbreaks. Results: A total of 765 acute gastroenteritis epidemics caused by norovirus were reported in Beijing, in which 85.88% (657/765) were cluster events and 14.12% (108/765) were outbreaks. Among the outbreaks, 70.37% (76/108) were reported in 2017; 84.26% (91/108) were reported in winter and spring; 88.89% (96/108) were reported in kindergartens, primary or secondary schools; 81.48% (88/108) were through person-to-person transmission; 93.52% (101/108) were caused by norovirus GⅡ infection. The risk of outbreaks in suburban and out suburb area were 1.84 times (95%CI: 1.13-3.02) and 3.78 times (95%CI: 1.62-8.82) as high as that in urban area, respectively. The risks of outbreaks in primary, secondary schools and other institutions were 6.26 times (95%CI: 3.53-11.10), 14.98 times (95%CI: 6.23-36.01) and 8.71 times (95%CI: 3.07-24.71) as high as that in kindergartens, respectively. The risk of outbreak in which patients having lower hospital visiting rate than the median rate of all events was 2.29 times than that in the context of having higher hospital visiting rate (95%CI:1.42-3.68). The risk of foodborne outbreak was 14.55 times as high as that transmitted through person-to-person (95%CI: 3.15-67.07). Conclusion: Measures such as strengthening the prevention and control of norovirus outbreaks in suburbs, primary schools, secondary schools and other institutions, promoting patients to visit the hospital actively, improving the management of foodborne events and kitchen workers should be taken to reduce the incidence of acute gastroenteritis outbreaks caused by norovirus.目的： 分析2014－2018年北京市诺如病毒急性胃肠炎暴发的影响因素。 方法： 收集2014年4月至2018年3月北京市诺如病毒急性胃肠炎聚集性事件及暴发资料，应用非条件logistic回归模型分析诺如病毒急性胃肠炎暴发的影响因素。 结果： 北京市共报告由诺如病毒感染引起的急性胃肠炎事件765起，85.88%（657/765）为聚集性事件，14.12%（108/765）为暴发。在暴发中，70.37%（76/108）发生在2017年；84.26%（91/108）发生在冬、春季节；88.89%（96/108）发生在托幼机构及中小学；主要传播途径为人传人（81.48%，88/108）；93.52%（101/108）为GⅡ组诺如病毒感染引起。多因素logistic回归分析结果显示，在近郊区及远郊区发生的事件，出现暴发的风险分别是城区的1.84倍（95%CI：1.13~3.02）及3.78倍（95%CI：1.62~8.82）；在小学、中学及其他机构发生的事件，出现暴发的风险分别是幼儿园的6.26倍（95%CI：3.53~11.10）、14.98倍（95%CI：6.23~36.01）及8.71倍（95%CI：3.07~24.71）；就诊率低于全部事件就诊率中位数的，发生暴发的风险是就诊率高的2.29倍（95%CI：1.42~3.68）；传播途径为食源性的事件，发生暴发的风险为人传人传播的14.55倍（95%CI：3.15~67.07）。 结论： 加强郊区、中小学及其他机构诺如病毒暴发疫情的防控力度，急性胃肠炎患者积极就医，做好食源性疫情的防控及厨工的健康管理，有助于减少诺如病毒急性胃肠炎的暴发。.