Expanded Program on Immunization Department, Tianjin Center for Disease Control and Prevention, Tianjin, People's Republic of China.
Institute of Medical Support Technology, Academy of Military Sciences, Tianjin, People's Republic of China.
Vaccine. 2018 Dec 18;36(52):7950-7955. doi: 10.1016/j.vaccine.2018.11.009. Epub 2018 Nov 9.
A big pertussis outbreak occurred in a primary school with high vaccination coverage in northern China. An investigation was carried out in order to calculate the attack rate and identify the risk factors.
Between May 12 and July 29, an investigation was carried out in the primary school, which included 383 students and 27 teachers. Three definitions were used to distinguish the cases: confirmed, epidemiologically linked and suspected cases. A total of 232 blood samples were collected and examined by ELISA among healthy children in another primary school.
A total of 138 suspected pertussis cases were counted, of which 116 students were confirmed. The attack rate among students was as high as 30.29%. The pertussis outbreak lasted 88 days, and had quaternary cases of transmission. Migrant children were almost four times as likely to catch the disease as local children (p = 0.005). In addition, students who had received the last dose of pertussis vaccine more than 4 years prior were three times more likely of becoming ill than those less than 4 years (p = 0.006). The average level of antibodies to pertussis was 30.99 IU/mL among healthy children. No statistically significant difference was observed between DTaP and DTwP (p = 0.843).
This pertussis outbreak in a primary school with high vaccination coverage was an evidence of the pertussis resurgence in China. The major risk factor we identified was the waning of immunity in the years after pertussis vaccination. Booster vaccination for students should be given.
中国北方一所高疫苗接种覆盖率的小学发生了一起严重百日咳疫情。为了计算发病率并确定危险因素，进行了一项调查。
在 5 月 12 日至 7 月 29 日期间，对该小学进行了调查，共调查了 383 名学生和 27 名教师。使用三种定义来区分病例：确诊病例、流行病学关联病例和疑似病例。在另一所小学中，共采集了 232 份健康儿童的血液样本，并通过 ELISA 进行了检测。
共统计到 138 例疑似百日咳病例，其中 116 例学生确诊。学生的发病率高达 30.29%。百日咳疫情持续了 88 天，出现了四级传播。流动儿童感染的风险几乎是本地儿童的四倍（p=0.005）。此外，在上次接种百日咳疫苗超过 4 年后接种的学生患病的可能性是不到 4 年的三倍（p=0.006）。健康儿童的百日咳抗体平均水平为 30.99 IU/mL。未观察到 DTaP 和 DTwP 之间存在统计学差异（p=0.843）。
这起高疫苗接种覆盖率小学的百日咳疫情表明中国百日咳疫情出现反弹。我们确定的主要危险因素是百日咳疫苗接种后数年免疫力下降。应给予学生加强免疫接种。
