Phase 2b Study Evaluating Safety and Effectiveness of Oral ShigETEC Vaccine to Prevent Shigella and ETEC in Healthy Adults Aged 18 to 50

What this Trial Is About

Researchers are studying the effectiveness of the oral, live, attenuated ShigETEC vaccine in preventing illness caused by Shigella flexneri 2457T in healthy adults aged 18 to 50 years. This randomized, double-blind, placebo-controlled Phase 2b trial aims to evaluate how well the vaccine works against a controlled infection and to monitor its safety and tolerability. The study has two main parts. In Stage 1, participants receive either the ShigETEC vaccine or a placebo orally four times on Days 1, 4, 7, and 10. Stage 2 begins about three weeks after the last dose and involves an oral dose of the Shigella flexneri 2457T bacteria to assess the vaccines ability to prevent disease. Stage 2 is conducted in an inpatient setting with close monitoring for signs of infection. Participants will be closely followed throughout both stages, including assessments of health, laboratory tests, and monitoring of any symptoms or side effects. Researchers will measure vaccine effectiveness up to 60 days after challenge and track safety for up to 12 months. Additional evaluations include stool sample testing for bacterial shedding and disease severity scores. The total study duration includes vaccination, challenge, and follow-up periods to ensure thorough data collection.

Safety, and Efficacy Study of ShigETEC, a Live, Attenuated, Oral Combination Vaccine to Prevent Shigella and ETEC Disease Delivered to Healthy Adults Ages 18 to 50 Years Old