Pre-exposure rabies prophylaxis for the international traveller: a decision analysis.

To determine for which travellers pre-exposure rabies prophylaxis is indicated, a decision tree-based model has been developed which enables the comparison of one million travellers going to rabies-endemic areas who receive a pre-exposure rabies prophylaxis to one million travellers also going to rabies-endemic areas who are not vaccinated. Using data obtained from a review of the literature, probabilities were assigned to each significant outcome. When numbers were not available, estimates were used and tested with a sensitivity analysis. Routine pre-exposure prophylaxis would prevent 0.054 cases per million adult travellers per month at a cost of 5 billion (thousand million) Canadian dollars. In the worst-case scenario, which concerns children, the cost per case prevented per year of stay would be $275 000 dollars. Our decision analysis leads us to believe that routine pre-exposure prophylaxis given to travellers heading for rabies-endemic regions of the world is not indicated. We conclude that pre-exposure rabies prophylaxis is a medical decision that must be individualized for every traveller and should be particularly considered for children at high risk of being exposed to rabies, who are leaving for a long stay (more than one year) and who will not have rapid access to medical services and rabies immunobiologics.