Phase 4 Study To Assess The Safety Of Vivotif At Different Release Titers Among Travelers

This is a multicenter (at travel clinics), phase 4 observational prospective cohort study in healthy adult male and female travelers for whom typhoid vaccination with Vivotif is recommended, as per standard practice.

The study will enroll 950 subjects who will be randomized at a ratio of 1:1 into two groups, A and B, of 475 subjects each. Group A will receive 6.9-10.0 x109 CFU/capsule and Group B will receive 4.0-6.8 x109 CFU/capsule, respectively.

All subjects will receive four doses of Vivotif. One dose per subject will be administered on Days 1, 3, 5 and 7.

Investigators, subjects and all personnel involved in running the study will not be aware of the actual release titer associated with the distributed lots. Blinding is maintained using the commercial packaging that does not include the actual value of the release titer.