The cost-effectiveness of HIV prevention targeting: how much more bang for the buck?

BACKGROUND: Although the targeting of human immunodeficiency virus (HIV) prevention to high-risk populations has been widely discussed, its benefits have not been quantified. METHODS: This analysis of cost-effectiveness combines an HIV epidemic model, target population scenarios, and data on the cost and impact of prevention. RESULTS: The number of HIV infections averted in 5 years with $1 million in annual prevention spending ranges from 164 in high-risk populations to 0.4 in very-low-risk populations. Fortyfold to two-hundredfold differences in prevention costs could equalize HIV infections averted. CONCLUSIONS: Targeting appears to provide substantial benefit and should be considered in allocation decisions about prevention.