How can HIV resources be best used to avert as many infections as possible?

Using geospatial modelling to optimize the rollout of antiretroviral-based pre-exposure HIV interventions in sub-Saharan Africa.

Gerberry DJ, Wagner BG, Garcia-Lerma JG, Heneine W, Blower S. Nat Commun. 2014 Dec 2;5:5454. doi: 10.1038/ncomms6454.

Antiretroviral (ARV)-based pre-exposure HIV interventions may soon be rolled out in resource-constrained sub-Saharan African countries, but rollout plans have yet to be designed. Here we use geospatial modelling and optimization techniques to compare two rollout plans for ARV-based microbicides in South Africa: a utilitarian plan that minimizes incidence by using geographic targeting, and an egalitarian plan that maximizes geographic equity in access to interventions. We find significant geographic variation in the efficiency of interventions in reducing HIV transmission, and that efficiency increases disproportionately with increasing incidence. The utilitarian plan would result in considerable geographic inequity in access to interventions, but (by exploiting geographic variation in incidence) could prevent ~40% more infections than the egalitarian plan. Our results show that the geographic resource allocation decisions made at the beginning of a rollout, and the location where the rollout is initiated, will be crucial in determining the success of interventions in reducing HIV epidemics.

Abstract access

Editor’s notes: With the flatlining of HIV resources, it is becoming increasingly important to identify how best to maximise the impact of HIV programmes. This study used geospatial HIV modelling and optimisation to compare two potential rollout plans for antiretroviral based microbicides. One was based on egalitarian principles, where every community has an equal chance of accessing microbicides. The other was based on the utilitarian principles, where settings at greatest risk are prioritised. Assuming a fixed amount of resources, the impact of these two different rollout plans was compared. Using data from South Africa, the authors found that the geographic focusing at provincial level could prevent more infections in the first year of the rollout. The findings illustrate how decisions made about where new prevention technologies are first introduced at the start of a programme rollout can strongly influence the scale of their impact. In particular, it highlights that roll out strategies that first focus on the most vulnerable communities could have greatest impact. The modelling approach used in this study is applicable to other settings with geographic heterogeneity in the HIV epidemic, and could be used to inform the implementation and evaluation of other HIV prevention programmes.

HIV modelling
Africa
South Africa
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