Cholera vaccination: a decision analysis.

OBJECTIVE: To examine the clinical impact and financial cost of a vaccination program for the prevention of cholera in North Americans travelling to endemic and epidemic regions by means of the principles of decision analysis and a decision tree as well as to illustrate the effect of case attack rates on the cost per case prevented by vaccination. DESIGN: Review of the scientific literature to establish the probabilities of each significant outcome as well as a decision analysis and partial economic evaluation. OUTCOME MEASURES: Clinical impact (attack rates for cholera among vaccinated and nonvaccinated travellers), rates of death associated with cholera and vaccine-associated adverse events (VAAEs), and the number of VAAEs and the vaccine cost per case prevented. MAIN RESULTS: On the basis of our assumptions (including a rate of one case of cholera per 500,000 journeys to endemic regions), to prevent one case of cholera a vaccination program would cost $28.67 million and be associated with 105 VAAEs. CONCLUSION: Routine vaccination of travellers to endemic areas cannot be recommended; however, for people travelling to regions with a high transmission rate vaccination should be considered.