Figure 1. Recommended strategy regions: $50 000 per quality-adjusted life-year threshold.

The figure recommends an HIV screening policy as a function of both the HIV prevalence in the target population (vertical axis) and the impact of HIV patient care on secondary transmission, R₀ (horizontal axis). R₀ can be interpreted as the lifetime number of secondary HIV infections averted when an HIV-infected person in a susceptible population is identified, counseled, and linked to treatment via HIV screening. Each prevalence value is associated with a specific incidence assumption (see Methods section for details). The figure recommends HIV screening policies, assuming that society is prepared to pay up to $50 000 per additional quality-adjusted life-year of health for its citizens. The dotted lines represent the 3 transmission impact scenarios described in Table 2: "favorable impact," "no effect of screening and treatment on transmission impact," and "adverse impact." The curves denote the circumstances under which a given HIV screening strategy is preferred. For example, assuming no impact on secondary transmission, a one-time screening is recommended for prevalences greater than 0.28% (solid circle). Assuming a favorable transmission impact, the one-time screening threshold falls to 0.20% (solid square); with an adverse transmission impact, it increases to 0.40% (solid triangle). The threshold population for screening every 5 years (assuming favorable transmission impact) is HIV prevalence of 0.45% and annual incidence of 0.0075% (solid diamond).