This project attempts to evaluate a new vaccination strategy for residents of endemic areas. A cluster-randomized trial involving the Vi polysaccharide vaccine and an active control (meningococcal A vaccine) was designed to determine the effectiveness and the feasibility of providing Vi vaccine under actual programmatic conditions in 2 populous townships of Hechi City. The vaccines used in this study are locally produced and licensed in China. A 1 year pilot phase will precede the actual Vi-demonstration project. Surveillance for typhoid fever cases will continue after the mass immunization campaign. A passive surveillance system to evaluate adverse events following immunization will be implemented. Socio-economic studies will be conducted in parallel to the effectiveness evaluation. The knowledge, attitudes, beliefs and practices among parents and health care providers regarding typhoid illness, treatment and prevention will be assessed. Logistic, feasibility and vaccine costs will also be determined.