Cost-effective allocation of government funds to prevent HIV infection.

Relative to the magnitude of the epidemic, government funds available for HIV prevention are scarce. To optimize use of funds, we applied a mathematical model of the cost of HIV prevention interventions using national data on HIV risk-group size and HIV prevalence. This procedure suggested an allocation of funds across nine interventions to potentially prevent an estimated 20,000 infections annually, compared with the estimated 7,300 infections potentially prevented through four interventions now recommended by the Centers for Disease Control and Prevention (CDC). The optimal allocation will involve a combination of intensive interventions for high-prevalence populations and inexpensive large-scale interventions for lower-prevalence populations.