A vaccine consisting of killed whole-cell V. cholerae O1 in combination with a recombinant B-subunit of cholera toxin (WC/rBS) has been marketed since the early 1990s. This killed vaccine is well tolerated and confers high-level (85–90%) protection for 6 months after the second immunization in all vaccinees aged more than 2 years. The level of protection is still about 50%, 3 years after immunization in vaccinees who were aged over 5 years at the time of vaccination. Primary immunization consists of two oral doses 7–14 days apart for adults and children aged 6 years and over. For children aged 2–5 years, three doses are recommended. Intake of food and drinks should be avoided 1 hour before and after vaccination. If the second dose is delayed for more than 6 weeks, vaccination should be restarted. Following primary immunization, protection against cholera may be expected after about 1 week. Booster doses are recommended after 2 years for adults and children aged 6 years and over, and every 6 months for children aged 2–5 years. The vaccine is not licensed for individuals under 2 years of age.
In studies of travellers to countries or areas reporting cholera outbreaks, WC/rBS was also found to induce approximately 50% short-term protection against diarrhoea caused by enterotoxigenic Escherichia coli (ETEC).
Two closely related bivalent oral cholera vaccines are available in India and Viet Nam. These killed whole-cell vaccines are based on V. cholerae serogroups O1 and O139 and do not contain the toxin B-subunit; they are reported to be safe and efficacious, providing 66–67% protection for at least two years against clinically significant cholera in countries or areas reporting outbreaks. The Indian vaccine is intended for both the national and the international market.
Type of vaccine:
a) Killed oral O1 whole-cell with B-subunit
b) Killed oral O1 and O139
Number of doses:
a) Two doses (minimum 1 week and maximum 6 weeks apart). Three doses for children aged 2–5 years (minimum 1 week and maximum 6 weeks apart).
b) Two doses 14 days apart for individuals aged ≥1 year. One booster dose is recommended after 2 years.
Contraindications: Hypersensitivity to previous dose
Adverse reactions: Mild gastrointestinal disturbances reported
Before departure: 2 weeks
Consider for: Travellers at high risk (e.g. emergency or relief workers)
Special precautions: None