A controlled field trial of an aluminum phosphate-adsorbed cholera vaccine in Calcutta.

A controlled field trial to determine the efficacy of a single dose of an aluminium phosphate-adsorbed cholera vaccine was conducted in Calcutta during 1975-77. An aluminium phosphate-adsorbed tetanus toxoid was used as the placebo. Follow-up of the immunized volunteers for a period of two years showed that the adsorbed cholera vaccine provided 100% protection to children under five years of age for 6 months, 88.9% for 12 months, and 91.7% for 18 months (P<0.05). The overall protection for all age groups was 58.5% for 18 months. There were no serious side effects following the anti-cholera inoculations.