[Adverse events following immunization and causality assessment of an adverse event following immunization].

Several fatal events occurred in Hunan, Guangdong and Sichuan Province in December, 2013. The events were reported by the news media, which followed growing public concern. Currently, more and more vaccines were developed and the immunization was adopted for more objectives. The clinicians, especially pediatricians will face a growing number of clinical problems related to the vaccine. The clinicians should pay attention to learn more knowledge about vaccines. This article describes the definition and classification of "adverse events following immunization" and "serious vaccine product-related reactions", and the signifcance and conclusion of causality assessment following immunization.