Abstract: The method of causality assessment of Adverse Events Following Immunization(AEFI) is an important part for the vaccine adverse reaction monitoring and evaluation. At present there is not a normative method for causality assessment of AEFI internationally. This article introduced and analyzed three methods from the Global Advisory Committee on Vaccine Safety of WHO, Clinical Epidemiology Research Center of Canada, Clinical Immunization Safety Assessment of US. The suggestions were put forward for the work of causality assessment of AFEI.

Key words: adverse events following immunization, method of causality assessment