2020年重庆市巴南区某小学水痘暴发疫情的调查分析

Investigation and analysis of an outbreak of chickenpox in a primary school in Ba′nan District of Chongqing in 2020

目的 调查2020年重庆市巴南区某小学1起水痘暴发疫情,了解水痘疫情流行病学特点,为水痘疫情防控制定相应依据。方法 通过现场流行病学调查收集2020年重庆市巴南区某小学发生1起水痘暴发疫情病例信息,使用描述性分析水痘罹患率和流行病学特征,采用病例对照研究方法分析水痘疫苗保护效果。采用SPSS 25.0软件进行χ^(2)检验,检验水准为α=0.05。结果 本起暴发疫情持续96 d,涉及5个年级17个班,水痘共发病111例,罹患率13.69%(111/811);病例组水痘疫苗接种率45.95%,对照组接种率61.86%,接种疫苗的学生水痘罹患率是未接种的0.52倍(95%CI:0.340~0.817),差异有统计学意义(χ^(2)=8.650;P=0.003);接种1剂次水痘疫苗的学生患水痘的危险性是2剂次的7.97倍(95%CI:3.190~19.070),差异有统计学意义(χ^(2)=25.610;P<0.001)。结论 建立学校水痘免疫屏障,需加强水痘疫苗接种宣传工作,尤其是2剂次水痘疫苗接种工作,是控制学校水痘暴发疫情的有效措施。

Objective To investigate a varicella outbreak in a primary school in Ba′nan District of Chongqing in 2020,to understand the epidemiological characteristics of this varicella epidemic,and to formulate corresponding evidence for the prevention and control of the epidemic.Methods A field epidemiological investigation was carried out to collect case information of the varicella outbreak in the primary school in Ba′nan District of Chongqing in 2020.The incidence rate and epidemiological characteristics of varicella were analyzed by descriptive methods,and a case-control study was carried out to analyze the protective effect of varicella vaccine.Chi-square test was performed by SPSS 25.0 software,and the test level was α=0.05.Results The outbreak lasted for96 days,involving 17 classes in 5 grades,with 111 varicella cases,and the incidence rate was13.69%(111/811).The inoculation rate of varicella vaccine was 45.95%in the case group and61.86%in the control group.The incidence rate of varicella among vaccinated students was 0.52times that of unvaccinated students (95%confidence interval CI:0.340-0.817),and the difference was statistically significant(χ^(2)=8.650,P=0.003).The risk of varicella of students who had received one dose of varicella vaccine was 7.97 times that of students who had received two doses of varicella vaccine (95%CI:3.190-19.070),and the difference was statistically significant(χ^(2)=25.610,P<0.001).Conclusions To establish a chickenpox immunization barrier in schools,it is necessary to strengthen the publicity of chickenpox vaccination,especially the two-dose chickenpox vaccination,which is an effective measure to control the outbreak of chickenpox in schools.