Since this oral bivalent whole-cell cholera vaccine has not been tested in Bangladesh before, the study will be carried out in 3 age groups, i.e. adults, followed by toddlers and younger children. These study participants will be recruited from the field site in Mirpur. For this purpose, 55 adults (18-45 year old) will be given 2 doses of the bivalent whole-cell cholera vaccine and 55 adults will be given placebo. Safety will be clinically monitored for side effects for 3 days after each dose of study agent by home visits. Participants will be randomized to receive either 2 doses of the vaccine or placebo, given 14 days apart.