Cost-effectiveness analysis of vaccination against hepatitis A in travellers.

Hepatitis A virus (HAV) infection is a substantial risk for travellers from low endemic countries to high endemic destinations. Costs and effects of alternative options for prevention were compared using formal decision analysis. General indications for the optimal prevention of hepatitis A were derived from a cost-effectiveness analysis. Various possible strategies for prevention of hepatitis A in travellers were compared to doing nothing: active immunisation using either the existing vaccine (HAVRIX 720) or the new vaccine (HAVRIX 1440); first screening for the presence of HAV antibodies and then vaccinating only susceptibles; and passive immunisation with immunoglobulin. Using a number of assumptions as baseline and for an average duration and frequency of travel from low to high endemic countries, threshold values were obtained for the choice between passive and active immunisation. Passive immunisation remains the most cost-effective prevention strategy for those expected to travel not more frequently than twice over the next 10 years and for short stays (7,000-9,000 pounds per infection prevented). For travellers expected to travel three or more times in 10 years or for trips exceeding a period of 6 months, active immunisation before the first trip is the most cost-effective option (7,500 pounds or less per infection prevented). When travel frequency increases to once a year in the next 10 years, costs per infection prevented decrease to about 3,500 pounds. Screening for the presence of antibodies before vaccination is only justified for older travellers or those leaving from countries with moderate endemicity, i.e., with an average HAV prevalence of at least 30%.