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

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.