HIV prevention where it is needed most: comparison of strategies for the geographical allocation of interventions

Abstract

IntroductionA strategic approach to the application of HIV prevention interventions is a core component of the UNAIDS Fast Track strategy to end the HIV epidemic by 2030. Central to these plans is a focus on high‐prevalence geographies, in a bid to target resources to those in greatest need and maximize the reduction in new infections. Whilst this idea of geographical prioritization has the potential to improve efficiency, it is unclear how it should be implemented in practice. There are a range of prevention interventions which can be applied differentially across risk groups and locations, making allocation decisions complex. Here, we use mathematical modelling to compare the impact (infections averted) of a number of different approaches to the implementation of geographical prioritization of prevention interventions, similar to those emerging in policy and practice, across a range of prevention budgets.MethodsWe use geographically specific mathematical models of the epidemic and response in 48 counties and major cities of Kenya to project the impact of the different geographical prioritization approaches. We compare the geographical allocation strategies with a nationally uniform approach under which the same interventions must be applied across all modelled locations.ResultsWe find that the most extreme geographical prioritization strategy, which focuses resources exclusively to high‐prevalence locations, may substantially restrict impact (41% fewer infections averted) compared to a nationally uniform approach, as opportunities for highly effective interventions for high‐risk populations in lower‐prevalence areas are missed. Other geographical allocation approaches, which intensify efforts in higher‐prevalence areas whilst maintaining a minimum package of cost‐effective interventions everywhere, consistently improve impact at all budget levels. Such strategies balance the need for greater investment in locations with the largest epidemics whilst ensuring higher‐risk groups in lower‐priority locations are provided with cost‐effective interventions.ConclusionsOur findings serve as a warning to not be too selective in the application of prevention strategies. Further research is needed to understand how decision‐makers can find the right balance between the choice of interventions, focus on high‐risk populations, and geographical targeting to ensure the greatest impact of HIV prevention.

PrEP uptake and adherence in relation to HIV-1 incidence among Kenyan men who have sex with men

“…Mathematical models using local epidemiological and behavioral data provide insights on which approach would yield the greatest reduction of HIV-1 transmission [8] , [9] , [10] . Results from a modelling study using data from Nairobi suggested that, in a setting with limited resources, decreasing overall HIV-1 infections could best be achieved when male sex workers were prioritized for PrEP and ART initiation, followed by prioritizing MSM not reporting sex work and FSW [10] .…”

Targeting the right interventions to the right people and places

“…Third, recommendations that come out of geospatial analyses should be translated into policy with caution. Oversimplification of geospatial conclusions may result in lower impact than the theoretical maximum [ 35 , 36 ] due to funds being trapped in allocations which are locally inefficient. Models may also be naive to the additional costs of changing intervention programs or implementing them only in certain regions or populations in a country.…”

Willingness to use HIV prevention methods among vaccine efficacy trial participants in Soweto, South Africa: discretion is important

“…The observation of herd immunity in vaccinology suggests the importance of a uniform approach to prevention, even for HIV. In one mathematical model, if prevention resources were restricted to high-prevalence locations, 41% fewer infections would be averted than if resources were available at all locations regardless of HIV prevalence [ 26 ]. The desire for participants in our study to have their HIV prevention method blend into their lifestyle is an important concept for discussion, because it prompts a conversation about how HIV prevention methods could be developed to be widely palatable for a uniform, rather than a restricted, approach.…”