Study to Find and Confirm Safe Dose of Shigella sonnei 53G Infection in Healthy Kenyan Adults Aged 18 to 45

What this Trial Is About

Diarrhea caused by Shigella, known as shigellosis, is a significant public health concern with no licensed vaccines currently in routine use. Researchers are establishing a human infection study HIS using Shigella sonnei 53G in Kenyan adults to help develop a vaccine model and better understand immune responses and factors influencing disease susceptibility. This study is a Phase 1 trial involving dose-finding and dose-verification phases to achieve about a 60% infection rate safely. The study involves two phases over 12 to 14 months. Phase A will enroll up to 40 volunteers receiving varying doses of lyophilized Shigella sonnei 53G bacteria to find the dose causing infection in at least 60% of participants. Depending on infection rates, doses may increase or decrease by 500 CFU in subsequent groups. Phase B will enroll 30 volunteers to confirm the infection rate with the selected dose. All participants will receive curative treatment with Ciprofloxacin after challenge. Participants will stay as inpatients for about 12 days and have outpatient follow-up for approximately 12 months. Researchers will monitor adverse events, infection rates, bacterial shedding, and antibody responses over time. Safety and infection success are primary outcomes. Volunteers will undergo regular assessments during the study, including laboratory tests and close monitoring of symptoms and immune responses to understand Shigella infection better.

Shigella Sonnei 53G Human Infection Study in Kenyan Adults