CISA strives to understand adverse events following immunization (AEFIs) in order to advise providers and patients regarding management and revaccination. Clinical consult reviews are part of this process. Many of the AEFIs discussed in the consultations are rare, and there is often scarce literature to assist in determining a causal relationship with the vaccine in question. VAERS reviews can be informative, but are fraught with limitations, and in general should not be used as indicators of causality. It is the purpose of this project to establish and maintain a large database which summarizes vaccine and demographic information for all members of the Kaiser Permanente Northern California Health Plan (KPNC). The purpose of this database is to serve as the repository for vaccine-specific data which can be used to determine the expected proportion of recent vaccination for cases in vaccine safety studies. This will allow for rapid analyses of rare or unusual (AEFI), which can be used to inform discussions of individual events. This type of analysis has been made possible by the development of newer methods for studying vaccine safety, specifically the case-centered method. Once we establish the tables containing summarized data, we will repeatedly test the system, and evaluate CISA experts’ opinions on its value for the clinical consult service. Feedback will be used to further refine the system.