Cost-effectiveness analysis of hepatitis A prevention in travellers

The advent of new vaccines and the changing epidemiology of hepatitis A call for an update of the economic evaluation of costs and benefits associated with the various alternative preventative strategies. A decision-tree-based model has been developed which enables the calculation of expected costs and expected numbers of hepatitis A virus HAV infections based on different intervention strategies. The model is sufficiently generic to allow for the evaluation of both population-wide strategies and strategies targeted at particular risk groups. An economic analysis focusing on travellers from Europe to high-endemic countries compared a non-intervention strategy to the following three strategies: active immunization with HAV vaccine; screening for HAV antibodies and vaccinating only susceptibles; passive immunization by means of immunoglobulin. The net cost per HAV infection prevented proved very sensitive to a number of important input parameters of the model. These included epidemiological characteristics such as HAV attack rate and prevalence of immunity, behavioural characteristics such as compliance with the vaccination scheme and vaccine characteristics such as rate and duration of protection. Our estimated expected cost per HAV infection prevented among Belgian travellers to high-endemic countries for three weeks per year over ten years amounts to approximately US$4880 for active immunization, US$5621 for screening followed by vaccination of susceptibles and US$29932 for passive immunization. Although these estimates are clearly sensitive to a number of crucial assumptions pertaining to the input parameters of the model, it seems safe to conclude that vaccination is more cost-effective than the currently recommended passive immunization with immunoglobulin. Screening for antibodies before vaccinating may be more cost-effective for risk groups having a sufficiently high prevalence of immunity.