Infants will be identified through a community survey in urban neighborhoods in the city of Delhi, India and screened at 6 weeks of age if parental consent is available. They will be given the first dose of EPI vaccines at this age. Of those screened, eligible infants will be given the first administration of the test vaccine/placebo at 8 weeks of age if they meet the enrollment inclusion criteria, and consent is available. The safety profile will be studied through daily home visits for 14 days post administration. Stool specimens will be collected before vaccination (day 0) and on days 3, 7 and 28 post administration of vaccine/placebo. Subsequently, two contacts will be made; a home visit on day 21 and a clinic visit on day 28. On the day 28 visit, a stool and blood specimen will be collected. Prior to each administration of vaccine/placebo the infants will be assessed for any contraindications.