2018—2022年合肥市学校诺如病毒感染疫情特征分析

Epidemic characteristics of Norovirus infection in schools in Hefei City from 2018 to 2022

摘要:

目的 了解合肥市学校诺如病毒感染疫情的流行特征,为校园诺如病毒感染预防与控制提供科学依据。方法 采用描述性流行病学方法,分析2018—2022年合肥市各县(市、区)疾病预防控制中心上报的诺如病毒感染疫情调查报告和合肥市疾病预防控制中心实验室检测结果等资料,比较诺如病毒感染罹患率、报告及时性、疫情持续时间、临床症状及诺如病毒GⅠ、GⅡ分型等相关指标。结果 2018—2022年合肥市共发生学校诺如病毒感染疫情217起,发病3 002例,波及人口314 006人,年均罹患率为0.82%~1.32%。其中幼儿园疫情最多,为116起,占53.46%,罹患率2.87%。时间呈双峰分布,集中在每年3—6月和9—12月。暴发疫情的罹患率、疫情持续时长均高于聚集性疫情(均P＜0.001)。疫情接报时长与接报时发病数、疫情持续时长均呈正相关(r值分别为0.182、0.783,均P＜0.001)。随着学业阶段提升,腹泻症状呈上升趋势(χ²_趋势=743.236,P＜0.001),呕吐症状呈下降趋势(χ²_趋势=386.888,P＜0.001), 腹泻和呕吐两者症状皆有呈上升趋势(χ²_趋势=327.264,P＜0.001),发热呈下降趋势(χ²_趋势=15.717,P＜0.001)。肛拭子标本阳性检出率(60.10%)高于呕吐物和环境标本(分别为38.71%、 14.29%;χ²=135.685,P＜0.001)。实验室明确诺如病毒GⅠ、GⅡ分型疫情181起,其中GⅠ型28起,占15.47%,GⅡ型149起,占82.32%。结论 学校是诺如病毒感染高发场所,开学季应严格落实各项防控措施,提高呕吐、腹泻等症状监测敏感性,做到早发现、早报告、早处置。

Abstract:

Objective To understand the epidemic characteristics of Norovirus infection in schools in Hefei City, and provide scientific basis for the prevention and control of Norovirus infection in schools. Methods The investigation reports of Norovirus infection reported by the centers for disease control and prevention (CDC) of all counties (cities and districts) in Hefei City and the laboratory test results of Hefei CDC from 2018 to 2022 were analyzed by descriptive epidemiological methods. The related indicators of Norovirus infection, including the attack rate, timeliness of reporting, duration of epidemic, clinical symptoms, as well as GⅠand GⅡ classification of Norovirus were compared. Results From 2018 to 2022, there were 217 school Norovirus infections outbreaks in Hefei City, with 3 002 cases and 314 006 affected people. The average annual attack rate ranged from 0.82% to 1.32%. Most cases were from kindergartens, there were 116 cases, accounting for 53.46%, with an average attack rate of 2.87%. The time distribution was bimodal, concentrated in March-June and September-December each year. The attack rate and duration of outbreaks were both significantly higher than those of clustering epidemics (both P<0.001). Positive correlation existed between the timeliness of reporting and the number of outbreaks at the time of receiving the report as well as the duration of the epidemic (r=0.182, 0.783, respectively, both P<0.001). With the advancement of the academic stage, the symptom with diarrhea showed an increasing trend (χ²_trend=743.236, P<0.001), the symptom with vomiting presented a decreasing trend (χ²_trend=386.888, P<0.001), and the symptoms with both diarrhea and vomiting presented an increasing trend (χ²_trend=327.264, P<0.001), while the symptom with fever presented a decreasing trend (χ²_trend=15.717, P<0.001). The positive detection rate of anal swab specimens (60.10%) was higher than that of vomit and environmental specimens (38.71%, 14.29%, respectively, χ²=135.685, P＜0.001). The laboratory identified 181 cases with Norovirus GⅠ and GⅡ subtypes, including 28 cases of GⅠsubtype, accounting for 15.47%, and 149 cases of GⅡsubtype, accounting for 82.32%. Conclusion Schools are locations with high incidence of Norovirus infection. At the beginning of the school season, various prevention and control measures should be strictly implemented to improve the monitoring sensitivity of symptoms like vomiting, diarrhea, and so on, so as to achieve early detection, early report and early treatment.