Cost-effective analysis of hepatitis A prevention in Ireland.

Abstract OBJECTIVE: The purpose of this study was to determine the most cost-effective prevention strategy against hepatitis A virus (HAV) infection for healthcare workers and the general population at risk in Ireland. METHODS: Four prevention strategies were compared: active immunization with Havrix Monodose (1440E.U); screening for anti-HAV antibody and then vaccinating; passive immunization; screening for anti-HAV antibody and then passive immunization. The cost-effective ratio was calculated for each prevention strategy. Threshold analysis, sensitivity analysis, and model extension to include indirect cost from work days lost and secondary attack rates through horizontal transmission were also derived. RESULTS: The medical costs were lowest and the infection rate highest when no preventive action was taken. Vaccination was most cost effective when the prevalence of immunity was 45% or less, reducing the infection rate by 98% when compared to nonprevention. Screening before vaccination was most cost effective when the prevalence of immunity was greater than 45%. Passive immunization and screening before passive immunization were not comparable to the other strategies in cost effectiveness. Sensitivity analysis showed that the cost-effective ratio for vaccination was dependent on vaccine price, incidence of HAV, and prevalence of immunity in the target group. Extending the model to include indirect costs further increased the cost effectiveness of vaccination. CONCLUSION: The best cost-effective strategy relates to target group immunity. Where HAV immunity is 45% or less, vaccination is the strategy of choice and when immunity is greater than 45%, then screening followed by vaccination should be used. This study can be used to provide a framework within which choices can be made to achieve better health for less cost.