Vi polysaccharide typhoid vaccine (International Vaccine Institute)

The Vi polysaccharide typhoid vaccine is a subunit vaccine composed of the purified Vi capsular polysaccharide (Vi antigen) of *Salmonella enterica* serovar Typhi. Developed and promoted by the International Vaccine Institute (IVI) for use in typhoid-endemic regions, the vaccine induces active immunity by stimulating the production of Vi-specific IgG antibodies. These antibodies prevent the bacteria from adhering to and invading host tissues. The vaccine is typically administered as a single intramuscular injection and is primarily used in public health programs targeting school-aged children in low- and middle-income countries. In clinical trials conducted by IVI, such as the Phase 4 cluster-randomized trial in Hue City, Vietnam, a Hepatitis A vaccine is frequently employed as an active control to evaluate the feasibility, effectiveness, and cost-effectiveness of the typhoid immunization program.

Other names

Typhoid Vi vaccineVi vaccineVi capsular polysaccharide vaccine