Oral cholera vaccine study: Zanzibar
The "Pre-emptive Use of Cholera Vaccine in Vulnerable Populations" took place in Zanzibar between October 2006 and February 2012. Led by IVR, the project was a collaborative initiative with the Global Task Force on Cholera Control, the Ministry of Health and Social Welfare in Zanzibar, the International Vaccine Institute and the Swiss Tropical Public Health Institute.
The goal of the project was to assess the feasibility and effectiveness of cholera vaccination in Zanzibar to control the disease. Other objectives were to determine community perception of the disease and acceptance of cholera vaccine; vaccine cost-effectiveness; and the validity of establishing and maintaining a global cholera vaccine stockpile.
The vaccine chosen for the project was the WC-rBS vaccine Dukoral®, used primarily as a travellers’ vaccine in Europe. This oral vaccine consists of killed whole cells of different strains of Vibrio cholerae O1 and the B subunit of the cholera toxin. It requires two doses administered 1–6 weeks apart and a buffer that is mixed with the vaccine and water, and was chosen because it was the only WHO pre-qualified cholera vaccine when the project was launched.
The following project activities have been completed:
- a pilot vaccination project in high-risk areas along with operational research studies;
- tools developed and field tested to aid in rapid diagnosis, determining where and when to vaccinate in endemic settings, and in implementing vaccination;
- a vaccine effectiveness study assessed direct and indirect protective effects;
- socio-economic and behavioural research into leadership and community perceptions and acceptance was conducted in Zanzibar, Kenya and the Democratic Republic of Congo;
- an analysis on the financial and logistical feasibility of establishing and managing a global cholera vaccine stockpile; and
- review of how to translate study findings into global and national policy, and presentations to the WHO Strategic Advisory Group of Experts (SAGE).
At the closing workshop of the study held in February 2012 in Zanzibar, participants endorsed the government’s goal to eliminate indigenous cholera transmission in Zanzibar within 10 years through oral cholera vaccination. This goal needs to be complemented with the provision of clean water and adequate sanitation to sustain elimination.