The overall aim of this project is to develop effective vaccines against two of the most common gastrointestinal pathogens, i.e. enterotoxin-producing Escherichia coli (ETEC) and Helicobacter pylori, especially for use in developing countries. This includes studies to elucidate immune mechanisms and antigens of importance for protection against diseases caused by these bacteria and to construct and evaluate promising candidate vaccines for safety and immunogenicity, initially in animals and subsequently in humans. It also includes a search for new ETEC colonization factors and analyses of emerging ETEC clones by means of whole genome sequencing. A new oral ETEC candidate vaccine developed by us, consisting of recombinant E. coli bacteria over-expressing the most important ETEC colonization factors and a toxoid will be evaluated alone and together with a promising mucosal adjuvant for safety and immunogenicity in Phase I/II studies, initially in Sweden and subsequently in descending age groups in Bangladesh. The aim is also to identify simple interventions such as calorie and micronutrient supplementation, changed breast feeding patterns, anti-parasite treatment that may improve immune responses against enteric vaccines in children in developing countries. Vaccine strains that overexpress putative protective H. pylori antigens will also be constructed and tested for protective efficacy in experimental animals.. This project was identified by RTI International for their own research purposes and some fields do not align with The GO Map categories. End dates were estimated as one year after the start date. The Project Type "Research, Clinical" may not accurately describe this project's focus but was used for all RTI International's Global Noncommunicable Diseases Initiative projects added in June 2018. Specialties were not analyzed. All project funding was valued in 2015 USD.