At a glance
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A Double-Blind Placebo Controlled Randomized Phase 2 Trial to Evaluate the Safety, Reactogenicity and Immunogenicity of a Live-Attenuated Shigella Sonnei Vaccine, WRSs2 and Determine Its Efficacy in a Challenge Model of S. Sonnei 53G in Healthy Adults
In Brief
A Phase 2 clinical trial evaluating Placebo, Shigella sonnei strain 53G, and 1 other intervention for Immunisation and Shigella Infection. Completed, enrolled 69 participants across 2 sites.
Detailed Summary
This is a trial to evaluate the safety, reactogenicity, immunogenicity and efficacy of a 10\^6 cfu dose of an oral live-attenuated S. sonnei vaccine candidate, WRSs2, in up to 120 healthy males and non-pregnant females aged 18-49, inclusive. This is a two-phase study, an outpatient WRSs2 vaccination phase and an inpatient S. sonnei 53G challenge phase. After the initiation of the study, two participants had Grade 3 diarrhea and/or vomiting in the days following vaccination. The vaccination dose was reduced to 5X10\^5, enrollment was changed to 2 arms and randomized 2:1 (vaccine: placebo). Participants with morbid obesity were excluded and weight loss medications prohibited. The Primary Objective of this study is to estimate combined vaccine efficacy of 2 doses of WRSs2 (10\^6 cfu or 5X10\^5 cfu) in preventing shigellosis, following challenge with S. sonnei strain 53G.
Study Details
Timeline
Interventions
0.9% Sterile Normal Saline, USP
1.5 x 10\^3 Colony Forming Units (cfu) Shigella sonnei 53G, a virulent strain of wildtype Shigella sonnei
10\^6 Colony Forming Units (cfu) dose of an oral live-attenuated Shigella sonnei vaccine candidate derived from a virulent S. sonnei strain Moseley (WRSs2)-a live, attenuated vaccine that has been manufactured under cGMP conditions at the WRAIR PBF