Evaluation of reactogenicity consisted of daily recording of symptoms reported by the mother/caregiver and twice-daily axillary temperature measurements for 14 days post administration of vaccine/placebo. Stool specimens were collected before administration of vaccine/placebo, twice during the week following administration (days 3 and 7), and at day 28 after administration to evaluate for vaccine virus shedding. Weekly recording of adverse events was also done for the next 2 weeks i.e. on days 21 and 28 post administration of vaccine/placebo. If gastrointestinal signs or symptoms occurred any time during the 4 weeks observation period, attempts were made to collect stool samples daily (maximum 2 per day) while the illness persisted, to be examined for the presence of the vaccine strains.