Approximately 40% more HIV infections could be prevented in Sub-Saharan Africa in the first year of a pre-exposure intervention rollout, by prioritising areas of high incidence, as opposed to focussing on equity of access to resources, reports a study in Nature Communications.

Approximately 34 million people worldwide are infected with HIV, with 3 million new infections per year in Sub-Saharan Africa alone. Pre-exposure HIV interventions, using anti-retroviral therapies, may soon be rolled out in Sub-Saharan African countries in an attempt to slow the rate of infection; however, resources are limited. The WHO recommends a number of different ethical principles to consider when deciding how to allocate scarce resources, including egalitarian and utilitarian principles.

Sally Blower and colleagues use geospatial modelling to determine which of these two principles makes for the most effective rollout plan. A plan according to utilitarian principles focuses on maximising societal benefits, while a plan following egalitarian principles prioritises equity of access to resources. Both plans use the same amount of resources.

The authors find that the efficacy of interventions increases disproportionately with increasing incidence of HIV in a given area and that focussing on these areas, as per the utilitarian plan, may lead to a 40% increase in prevented cases in the first year. The study is limited to geographic modelling and does not address the more complex problem of how to allocate resources between different HIV prevention methods.