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.
Who can participate
Age range18 Years – 49 Years
SexALL
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Inclusion criteria
✓. Provide informed consent prior to initiation of any study procedures.
✓. Are able to understand and comply with planned study procedures and be available for all study visits.
✓. Is 18-49 years of age inclusive and in sufficiently good health\* to be safely enrolled in this study as determined by medical history, medication use, and abbreviated physical exam.
Exclusion criteria
✕. Oral temperature is less than 100.4 degrees Fahrenheit.
✕. Pulse is 50 to 100 beats per minute (bpm), inclusive.
✕. Systolic blood pressure is 90 to 140 mmHg, inclusive.
✕. Diastolic blood pressure is 55 to 90 mmHg, inclusive.
✕. Females of childbearing potential\*\* may enroll if subject has practiced adequate contraception\*\*\* = / \> 30 days prior to enrollment and agrees to continue adequate contraception for the entire study.
✕. Females of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to enrollment.
What they're measuring
1
The Proportion of Participants With Shigellosis Following Challenge With Shigella Sonnei 53G Through Day 63 in the Pooled Group of Participants Receiving Two Doses of 10^6 Cfu or 5x10^5 Cfu of WRSs2 Compared to Participants Receiving Two Doses of Placebo.
Timeframe: Day 57 through Day 63
Trial details
NCT IDNCT04242264
SponsorNational Institute of Allergy and Infectious Diseases (NIAID)