自身对照的病例系列研究方法在疫苗安全性评价中的应用

Self-controlled case-series （SCCS） method as a tool for the evaluation on the safety of vaccine

疫苗安全性备受关注。评估罕见发生的不良事件与疫苗接种的关联时，采用经典流行病学研究设计通常面临可行性不足的问题。自身对照的病例系列研究（sccs）方法是队列研究设计的一种衍生形式，其优点是只需收集病例的暴露史等信息，估计暴露和特定事件在风险期与对照期的相对危险度；由于以自身作为对照，所有固定的混杂变量自然得到控制，因而具有较高的检验效能，且具有高效、经济的特性，适用于发生率极低的严重预防接种不良事件因果关联评估。该方法最重要的限制条件是要求结局事件不对后继暴露产生影响。

Safety on vaccine issues has been under greater concern. Epidemiologically, classical study designs on investigating the association between a rare adverse event and vaccine inoculation usually confronted with lower feasibility in practice. Self-controlled case series （SCCS） method was derived from cohort studies. The key advantage of this method is that it only uses data related to cases and trying to find relative incidence of events in the ＇ at risk＇ periods relative to the ＇controlled＇ periods. A further benefit of this method is that all the fixed confounders are controlled implicitly, by self-control, thus provides high statistic powers. With these advantages, SCCS is suitable for the causality assessment on rare but severe adverse events caused by immunization, which has been widely used, abroad. However, the methodology of SCCS is still being developed, and the areas in use have been expanded to the studies related to the safety and effectiveness of drugs, efficacy of vaccines as well as risk factors of disease.