This is a single-center, double-blind, placebo-controlled, Phase II vaccination and challenge study designed to confirm a human challenge model with E. coli strain LSN03-016011/A (LT+ (Labile toxin), ST- (Stable toxin), CS17), as well as collect expanded safety and immunogenicity data.~The study will be carried out in two phases:~Vaccination phase: up to 34 subjects will be randomized 1:1 to receive 2 doses of either VLA1701 or placebo orally. The doses will be given 7 days apart and subjects will be followed as an outpatient for safety.~Challenge Phase: 30 Subjects, out of the 34 subjects, will be challenged.~After challenge, subjects will be monitored for diarrhea and other signs/symptoms of enteric illness by daily medical checks, vital sign determinations, grading and weighing of all stools.
This is a single-center, double-blind, placebo-controlled, Phase II vaccination and challenge study designed to confirm a human challenge model with E. coli strain LSN03-016011/A.