Cholera remains a serious public health problem worldwide. Provision of safe water and food, establishment of adequate sanitation, and implementation of personal and community hygiene constitute the main public health interventions against cholera. These measures cannot be implemented fully in the near future in most cholera-endemic areas. A safe, effective, and affordable vaccine would be a useful tool for cholera prevention and control.The World Health Organization recently recommended that the newer generation cholera vaccines be considered in certain endemic and epidemic situations, but indicated that demonstration projects are needed to provide more information about the costs, feasibility, and impact of using these vaccines. Starting in the mid-1980s, following technology transfer from Prof Jan Holmgren in Sweden, Vietnamese scientists at the National Institute of Hygiene and Epidemiology (NIHE) in Hanoi developed and produced an oral, killed cholera vaccine for the country's public health programs (10). Since licensure of the oral cholera vaccine in Vietnam, more than 5 million doses have been administered without any report of serious adverse events.