The vaccine may be used in endemic areas in order to prevent typhoid.

It is also commonly used to protect people who are traveling to parts of the world where typhoid is endemic.

It is produced by the action of a single gene cluster in the cytoplasm and transported to the surface.

This antigen contributes to much of typhoid's virulence, and is important for the infection of intestinal epithelial cells.

Paratyphi C, the causative agent of paratyphoid fever C.[2] A newer conjugate form of the vaccine (Vi bound to a non-toxic recombinant Pseudomonas aeruginosa exotoxin A, or Vi-rEPA) has enhanced efficacy,[3] including protection of children under 5 years of age.