As the immune response to vaccines in naïve populations may differ from that in endemic populations, a Phase 1b clinical trial will be performed in Bangladesh. 

In endemic regions, the highest burden of Shigella and ETEC are in the 1-5 years age group. Therefore, protection should be ideally provided by immunization of infants at 6-11 months of age. With this objective in mind, the Phase 1b clinical trial will evaluate three escalating doses of the vaccine beginning in adults and progressing to 2-5 year-old children, then 12-23 month-old children and finally 6-11 month-old infants.  The ethical approval of the clinical trial will be obtained from the Ethical Review Committee (ERC) of icddr,b and the regulatory approval will be obtained from the Directorate General of Drug Administration (DGDA) of the government of Bangladesh.