Tang Q Y, Gao X Y, Song Y, Zhang Y T, Ran L, Chang Z R, Zhang Y P, Liu F F
Division of Infectious Diseases/Key Laboratory of Surveillance and Early Warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
Zhonghua Liu Xing Bing Xue Za Zhi. 2023 May 10;44(5):751-758. doi: 10.3760/cma.j.cn112338-20221109-00956.
To analyze the epidemiological characteristics of norovirus-caused acute gastroenteritis outbreaks in China, identify the factors influencing the scale of outbreaks, and provide scientific evidences for early control of norovirus infection outbreaks. The descriptive epidemiological analysis approach was applied to analyze the incidence of national norovirus infection outbreaks by using the data from the Public Health Emergency Event Surveillance System in China from January 1, 2007 to December 31, 2021. The unconditional logistic regression model was applied to analyze the risk factors that affected the outbreaks' scale. A total of 1 725 norovirus infection outbreaks were recorded in China from 2007 to 2021, with an upward trend in the number of the reported outbreaks. The southern provinces had their annual outbreak peaks from October to March; the northern provinces had two outbreak peaks from October to December and from March to June annually. The outbreaks occurred mainly in southeastern coastal provinces with a trend of gradual spread to central, northeastern and western provinces. The outbreaks mainly occurred in schools and childcare setting (1 539 cases, 89.22%), followed by enterprises and institutions (67 cases, 3.88%) and community households (55 cases, 3.19%). Human to human transmission was the main infection route (73.16%), and norovirus GⅡ genotype was the predominate pathogen causing the outbreaks (899 cases, 81.58%). The time interval between the onset of the primary case and the outbreak reporting () was 3 (2, 6) days and the case number of the outbreak () was 38 (28, 62). The timeliness of outbreak reporting was improved in recent years and the scale of the outbreaks showed a decreasing trend over the years, the differences in reporting timeliness and outbreak scale among different settings were significant (<0.001). The factors that affected outbreaks' scale included the outbreak setting, transmission route, outbreak reporting timeliness and type of living areas (<0.05). From 2007 to 2021, the number of the norovirus-caused acute gastroenteritis outbreaks increased in China and the more areas were affected. However, the outbreak scale showed a decreasing trend and the outbreak reporting timeliness was improved. It is important to further improve the surveillance sensitivity and reporting timeliness for the effective control of the outbreak scale.
为分析中国诺如病毒引起的急性胃肠炎暴发的流行病学特征，确定影响暴发规模的因素，为诺如病毒感染暴发的早期防控提供科学依据。采用描述性流行病学分析方法，利用中国突发公共卫生事件监测系统2007年1月1日至2021年12月31日的数据，分析全国诺如病毒感染暴发的发病情况。应用非条件logistic回归模型分析影响暴发规模的危险因素。2007年至2021年中国共记录1725起诺如病毒感染暴发事件，报告暴发数量呈上升趋势。南方省份的年度暴发高峰出现在10月至次年3月；北方省份每年有两个暴发高峰，分别在10月至12月和3月至6月。暴发主要发生在东南沿海省份，并有逐渐向中部、东北和西部省份蔓延的趋势。暴发主要发生在学校和托幼机构（1539起，89.22%），其次是企事业单位（67起，3.88%）和社区家庭（55起，3.19%）。人传人是主要感染途径（73.16%），诺如病毒GⅡ基因型是引起暴发的主要病原体（899起，81.58%）。首发病例发病至暴发报告的时间间隔（中位数）为3（2，6）天，暴发的病例数（中位数）为38（28，62）。近年来暴发报告的及时性有所提高，暴发规模呈逐年下降趋势，不同场所的报告及时性和暴发规模差异有统计学意义（P<0.001）。影响暴发规模的因素包括暴发场所、传播途径、暴发报告及时性和生活地区类型（P<0.05）。2007年至2021年，中国诺如病毒引起的急性胃肠炎暴发数量增多，波及范围扩大。但暴发规模呈下降趋势，暴发报告及时性有所提高。进一步提高监测敏感性和报告及时性对于有效控制暴发规模至关重要。
