MODEL-BASED EVALUATION OF HIV PREVENTION INTERVENTIONS

The ultimate goal of HIV prevention interventions is to reduce the spr ead of HIV; however, the effectiveness of these programs is seldom ass essed directly. Although direct measurement of an intervention's impac t via HIV seroincidence monitoring is usually unfeasible, mathematical models can be used to estimate the number of infections averted by th e intervention. This article describes three model-based summary measu res of sexually transmitted HIV risk and discusses their relevance to HIV program evaluation in general and economic efficiency analyses in particular The calculation of these measures is demonstrated with an i llustrative application to previously published data from an HIV preve ntion intervention for gay men.