The typhoid vaccination inoculates against typhoid fever, which is a systemic infection caused by the Gram-negative bacillus Salmonella typhi. Most salmonella types only cause local infection of the gastrointestinal tract; however, S. typhi is an invasive organism which can result in serious systemic infection.
This is a companion discussion topic for the original article at https://patient.info/doctor/drug-therapy/typhoid-vaccination