Zheng Qing-ming, Zeng Hua-tang, Wang Tie-qiang, Liu Yi, Wang Guang-li, Mei Shu-jiang, Zhang Shun-xiang
Guangming New District Center for Disease Control and Prevention, Shenzhen 518106.
Shenzhen Center for Disease Control and Prevention.
Zhonghua Liu Xing Bing Xue Za Zhi. 2013 Sep;34(9):906-10.
Both epidemiologic characteristics and transmission mode of a varicella outbreak among schoolchildren in Shenzhen city were studied and related control measures were discussed.
Case definition was established. Case-finding and face-to-face investigation were conducted, followed by analysis on distributions of time, place and persons of the outbreak. Association between possible modes of transmission and the outbreak was explored. Retrospective cohort study was carried out.
The overall attack rate of this outbreak was 4.4% (122 of 2742). The attack rate among primary schoolchildren(8.3%, 118/1419)was higher than that in the middle-school children(0.3%, 4/1323). There were no statistically significant differences on the attack rates between male and female students. A total of 22 classes from the 9 grades were affected by this outbreak and the aggregation of varicella cases was found in classes. The highest attack rates was found in the students of fifth grade(23.7%), followed by from the third grade (13.4%). The main transmission mode appeared to be close personal contact. The outbreak, with four peaks of incidence, lasted 72 days. Data from the investigation suggested that the primary case was introduced into the school during military training involved by the students. Activities related to physical examination for all the schoolchildren seemed to have contributed to the spread of this disease among classes. Delayed isolation of cases appeared to be the major factor causing the spread of disease among classes. Intensive off-school activities or free community bus for children did not seem to be associated with the spreading of the disease. 52.5% (64/122) of the cases had received one-dose of varicella vaccine, with the median of onset after the vaccination as 7 years. The results demonstrated that one single-dose vaccine or long vaccination period were factors related to the insufficient immunity that causing the outbreak of disease.
Varicella outbreak has been one of the most grievous public health problems in schools, posting challenges on the implementation of isolation measures, in particular. Once the chain of transmission is in place, it is difficult to make the universal measures effective within a short period.
研究深圳市在校儿童水痘暴发的流行病学特征及传播方式，并探讨相关防控措施。
制定病例定义，开展病例搜索与面对面调查，随后对暴发的时间、地点和人群分布进行分析，探究可能的传播方式与暴发之间的关联，进行回顾性队列研究。
本次暴发的总罹患率为4.4%（2742人中122例）。小学生的罹患率（8.3%，118/1419）高于中学生（0.3%，4/1323）。男女生的罹患率差异无统计学意义。9个年级的22个班级受此次暴发影响，班级内发现水痘病例聚集现象。罹患率最高的是五年级学生（23.7%），其次是三年级（13.4%）。主要传播方式似乎是密切的人际接触。此次暴发持续72天，有4个发病高峰。调查数据表明，首例病例是在学生参与军训期间传入学校的。全体在校儿童的体检相关活动似乎促成了该病在班级间传播。病例隔离延迟似乎是导致该病在班级间传播的主要因素。校外密集活动或儿童免费社区巴士似乎与疾病传播无关。52.5%（64/122）的病例接种过一剂水痘疫苗，接种疫苗后发病的中位数时间为7年。结果表明，单剂疫苗或接种时间过长是导致免疫力不足从而引发疾病暴发的因素。
水痘暴发一直是学校最严重的公共卫生问题之一，尤其对隔离措施的实施构成挑战。一旦传播链形成，很难在短时间内使普遍措施生效。
