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

This study tests a new oral vaccine called ShigETEC designed to protect against two common causes of severe diarrhea: Shigella bacteria and a strain of E. coli called ETEC. This type of diarrhea can be dangerous, especially in travelers and people in areas with limited clean water. **You may be eligible if:** - You are a healthy adult between 18 and 50 years old - You are not pregnant or nursing - You have a BMI between 19 and 40 - You are willing to stay at an inpatient unit for observation during part of the study - You agree to use effective birth control during the study **You may NOT be eligible if:** - You have a history of serious gastrointestinal disease (e.g., inflammatory bowel disease, liver disease) - You have taken antibiotics, probiotics, or antacids within 7 days before the vaccine dose - You have a weakened immune system - You work as a food handler or in direct patient/childcare - You have an immunocompromised person or a child under 2 in your household - You have had a confirmed Shigella or ETEC infection in the past 5 years - You have known allergies to study drug components (including soy or PEG) Talk to your doctor to see if this trial is right for you.