Phase 1 meCS6 + LT(R192G) Vaccine Study

The study will enroll approximately 60 volunteers. The vaccine is given as a drink in flavored soda water. Volunteers will either receive a 3-dose vaccination with doses spaced two weeks apart or a 4-dose vaccination with doses spaced 2 days apart depending upon their availability for follow-up. Once assigned to a vaccination schedule, volunteers will be randomly assigned to receive the meCS6 vaccine with or without the mLT adjuvant for all vaccine doses. Neither the study investigators nor the volunteers will know which group they are assigned. Volunteers will be asked to be available for clinic visits and telephone follow-ups during the study period and provide blood and stool specimens for testing.