中山市2013-2018年水痘突发公共卫生事件特征和水痘疫苗保护效果

Characteristics of varicella public health emergency events and effectiveness of varicella vaccine in Zhongshan city, 2013-2018

目的分析中山市水痘突发公共卫生事件(Public health emergency event,PHEE)的流行病学特征,评价1剂次水痘疫苗(Varicella vaccine,VarV)的保护效果(Vaccine effectiveness,VE)。方法通过中国PHEE管理信息系统收集中山市2013-2018年水痘PHEE,进行描述流行病学分析。采用1:2配对病例对照研究,收集病例组和对照组VarV免疫史,分析PHEE中VarV的VE。结果中山市2013-2018年共报告水痘PHEE 35起,发生水痘1094例,总罹患率为2.0%。小学、幼儿园、初中分别发生水痘PHEE 23起(65.7%)、11起(31.4%)、1起(2.9%)。发病高峰在冬季和春季。水痘PHEE报告时间与病例数、疫情持续时间均呈正相关(r=0.38,P=0.026;r=0.57,P<0.001)。3-12岁儿童接种1剂VarV的总VE(95%CI)为60%(50%-68%),接种后≤2年、3-4年、5-6年、7-8年、≥9年分别为78%(62%-87%)、73%(62%-81%)、58%(43%-69%)、36%(6%-56%)、34%(-18%-63%)。结论中山市水痘PHEE主要发生在小学和幼儿园;儿童接种1剂VarV的保护效果差且随时间推移而衰减。建议提高儿童2剂次VarV接种率。

Objective To analyze epidemiological characteristics of varicella public health emergency events(PHEEs)in Zhongshan city and estimate the vaccine effectiveness(VE)of one dose of varicella vaccine(VarV).Methods We used the National PHEE Reporting Information System to collect varicella PHEEs during 2013-2018 in Zhongshan for a descriptive analysis.We conducted a 1:2 matched case-control study and obtained VarV vaccination data for case and control groups to estimate VarV VE in varicella PHEEs.Results A total of 35 varicella PHEEs were reported in Zhongshan during 2013-2018;1094 varicella cases occurred,f or an overall attack rate of 2.0%.The numbers of varicella PHEEs in primary schools,kindergartens,and junior middle school were 23(65.7%),11(31.4%),and 1(2.9%),respectively.The incidence of PHEEs peaked in winter and spring.The reporting time of varicella PHEEs was positively correlated with the number of cases in PHEEs and the duration of PHEEs(r=0.38,P=0.026;r=0.57,P<0.001).The overall VE(95%CI)of one dose of VarV for children aged 3-12 years was 60%(50%-68%),with 78%(62%-87%),73%(62%-81%),58%(43%-69%),36%(6%-56%),and 34%(-18%-63%)for≤2,3-4,5-6,7-8,and≥9 years following vaccination,respectively.Conclusions Varicella PHEEs were common in primary schools and kindergartens of Zhongshan.The VE of one dose of VarV in children was poor and decreased over time.We suggest to improve coverage with two doses of VarV for children.