Jeju Center for Infection Control, Jeju, Korea.
Department of Preventive Medicine, Jeju National University School of Medicine, Jeju, Korea.
Epidemiol Health. 2018;40:e2018054. doi: 10.4178/epih.e2018054. Epub 2018 Nov 8.
Although the nationwide inoculation rate of varicella vaccine was approximately 95% in Korean children recently, the number of notified varicella cases is unexpectedly continuously increasing till now. To suggest some hypotheses regarding this discrepancy, an age-period-cohort (APC) analysis as a descriptive epidemiology study was conducted for children residing in Jeju-do, Korea.
The raw data were obtained from the nationwide database for insurance claim of healthcare fee provided by the National Health Insurance Service, Korea. The selection criteria were children aged 2-13 years who visited any healthcare center due to varicella from 2005 to 2016 while residing in Jeju-do. After calculating the birth cohort-specific crude incidence rates by age and year, the intrinsic estimator method was used to perform the APC analysis.
As the annual crude incidence rates decreased with increasing age between 2005 and 2016, the age and period effects also decreased. The intrinsic estimator coefficients suggesting the cohort effect shifted from positive to negative in 2011, the starting year of free varicella vaccine program in Jeju-do.
The results suggested that inoculated varicella vaccines have preventive effects. However, further studies to evaluate waning immunity would be needed.
尽管最近韩国儿童的水痘疫苗全国接种率约为 95%，但到目前为止，通报的水痘病例数量却出人意料地持续增加。为了对这种差异提出一些假设，我们对居住在韩国济州岛的儿童进行了年龄-时期-队列（APC）分析，这是一种描述性流行病学研究。
原始数据来自韩国国家健康保险服务提供的全民医疗保险费用理赔的全国性数据库。选择标准是 2005 年至 2016 年间因水痘而居住在济州岛的任何医疗保健中心就诊的 2-13 岁儿童。在按年龄和年份计算出生队列特异性的粗发病率后，使用内在估计器方法进行 APC 分析。
随着 2005 年至 2016 年年龄的增长，水痘的年粗发病率呈下降趋势，年龄和时期的影响也随之降低。2011 年，济州岛开始实施免费水痘疫苗接种计划，内在估计器系数提示队列效应从正转负。
结果表明接种的水痘疫苗具有预防作用。但是，需要进一步研究来评估免疫效力的下降。
