Shigella

The purpose of this study is to evaluate whether antibiotic treatment of non-dysentery Shigella associated watery diarrhea (NDSD) cases improves clinical outcomes and growth in children. Children with NDSD seeking care for diarrhea at the study hospitals in Bangladesh and Zambia will be enrolled and randomized to receive Azithromycin or placebo (a look-alike substance that contains no drug). Enrolled children will be followed for three months with household visits. The investigators will determine whether antibiotic treatment of NDSD reduces the duration of diarrhea and time to microbiological cure (shedding of Shigella in stool), and whether it improves growth in children compared with the placebo group.

Phase 1 trial to evaluate the Safety and Immunogenicity of Inventprise's (IVT) Shigella-04 in Healthy Young Adults

The purpose of this study is to evaluate the efficacy of the oral, live, attenuated ShigETEC vaccine against challenge with S. flexneri 2457T. In Stage 1 of this study, ShigETEC vaccine or placebo will be administered orally to healthy participants at a dose of 5x10\^10 CFU. This dose was tested in a Phase 1 trial and found to be safe when given 4 times with an interval of 3 days between each dose. The efficacy of ShigETEC vaccination will be evaluated in Stage 2 of this study, when participants will be challenged with S. flexneri 2457T. The study population will be healthy adult participants in the age of 18-50 years (inclusive), which are clearly defined in the study protocol.