2007年上海市某小学水痘爆发的流行病学调查

目的 通过调查上海市某小学的水痘爆发,分析水痘的传播途径和流行过程,评价水痘减毒活疫苗(Varicella Attenuated Live Vaccine,VarV)接种现状和保护率,探索水痘免疫对策.方法 2007年10月29日～2008年1月19日,对该校所有在校学生进行水痘发病问卷调查,同时查询VarV预防接种记录,分析爆发的危险因素,计算疫苗保护率.结果 1172名学生中,86.3%/4(1012/1172)在爆发前无水痘患病史,66.8%(676/1012)有VarV接种史.本次水痘发病73例,共形成3次发病高峰.病例主要分布在3～5年级,1、2年级无水痘发病,且VarV接种率较高[分别为85.3%(139/163)和76.8%(152/198)].无接种史的易感者水痘罹患率非常显著地高于有接种史者(x2=23.45,P<0.001),VarV保护率是68.5%(95%可信限为54.5%～75.5%).保护率随接种时间延长而明显下降(x2=4.131,P=0.0421).46.6%(34/73)的患者未能及时隔离,具有传播可能性.结论 低接种率、免疫时间较长和缺乏及时的报告隔离制度,是此次水痘爆发的主要危险因素.提高中、高年级小学生VarV接种率,深入评价免疫方案,改善水痘监测系统,对预防水痘爆发具有重要意义.

An Epidemiological Study on the Outbreak of Chickenpox in Elementary School in Shanghai in 2007

Objective An investigation to the outbreak of chickenpox in an elementary school in Zhabei District in Shanghai was carried out to analyze the route of transmission and the epidemics,to evaluate the coverage of varicella vaccination and vaccine effectiveness,to find out the strategies for varicella vaccination.Methods The duration of outbreak was from October 29,2007 to January 19,2008.Questionnaire survey conducted to all the students in the school during the outbreak.Individual vaccination records were re...