248   The Global HIV Epidemics among Sex Workers
Discussion These analyses help to frame the potential utility of the community empowerment-based comprehensive HIV prevention intervention for female sex workers under scenarios of both static national provision of ART and enhanced ART provision. Examining the utility of the intervention in terms of the cost per HIV infection averted and cost per Disability Adjusted Life Year Saved (DALY) allows policy makers and program managers concerned with comparative effectiveness and maximizing impact to directly compare program options. These costing exercises also allow us to generate national program costs for scale up, and when coupled with estimations of averted medical care cost, allow for improved long term planning in establishing national priorities by considering the net value of the intervention in terms of both the expense of the intervention, but also the potential cost savings over time. In general, the analyses presented herein indicate that the cost-effectiveness of the program is highly sensitive to epidemiologic factors associated with the geographic setting, and to a lesser degree the cost of labor across sites. Care was taken to collect the best available data and use the most realistic assumptions available for these analyses, yet there are some important limitations that should be highlighted. One important limitation is that across those countries selected for the modeling study, only Brazil had a community empowerment-based HIV prevention project with the necessary intervention evaluation data available for micro-costing. Thus, we took great care to generate highly detailed cost estimates from this site and worked closely with project staff from Brazil to generate estimates. This was important, as it formed the base-case analysis for cost estimations in Kenya, Thailand, and Ukraine. As a result, there is a greater degree of cost detail from Brazil that was used in the sensitivity analyses, and there is also the risk that some values estimated for other countries may be different in an actual implementation. The specific activity costs included were also those related to the intervention designed in the Brazilian context, which in keeping with the core principles of a community empowerment-based intervention model, would necessarily have to be adapted for the local context where the intervention would be implemented and take into account the extent to which existing public health services provide the necessary supplies for a comprehensive HIV prevention intervention, such as condoms and HIV/STI-relatedclinical services. To mitigate this risk we cross-checked our estimated values with a variety of other costing exercises that have been conducted in target settings, and examined the literature for labor cost estimates by country. We thus used a larger range of input values for cost items from Kenya, Thailand, and Ukraine for the sensitivity analyses to convey the increased uncertainty from these sites, and in the