上海市某职业学校水痘暴发调查

目的调查上海市某职业学校内发生的一起水痘暴发疫情，分析其流行特征和暴发原因，为采取针对性预防控制措施提供依据。方法根据病例定义开展病例搜索，应用描述性流行病学方法对暴发疫情流行特征进行分析。结果本次暴发水痘12例，罹患率0．78％，疫情波及4个班级，疫情持续37d。临床症状以单纯出疹伴发热为主，突破性病例占25．00％。病例所在班级中有接种史的罹患率为4．69％，无接种史的罹患率16．67％，无接种史的罹患率显著高于有接种史者，疫苗保护率74．13％。结论学生间接触及突破病例的出现可能是暴发疫情扩散的主要原因，建议提高水痘疫苗接种率，同时增加水痘疫苗接种剂次数以减少突破病例发生。

Objective To investigate a variceUa outbreak in a vocational school and to analyze the epidemiological characters and reasons of the outbreak, so as to explore the intervention strategies. Methods Cases were identified according to the case definition. The epidemiological characteristics of the outbreak were depicted. Results There were 12 cases ofvaricella and the attack rate reached 0.78%. The outbreak lasted 37 days, which spreaded to four classes. Rash associated with fever were main clinical symptoms. The attack rate in non-vaccinated students （ 16.67% ） was higher than those vaccinated （ 4.69% ） . Vaccine efficacy （ VE ） was 74.13%. Conclusions Contacting between students and breakthrough cases are the main reasons for this outbreak.It is suggested that we should improve varicella vaccine coverage, at the same time practice secondary varicella vaccine immunization program to reduce breakthrough case occurred.