Objectives Combination packages for HIV prevention can leverage the effectiveness of biomedical and behavioural elements to lower disease incidence with realistic targets for individual and population risk reduction. We investigated how sexual network structures can maximise the effectiveness of a package targeting sexually active adults in sub-Saharan Africa (SSA) with intervention components for medical male circumcision (MMC) and sexual partnership concurrency (having >1 ongoing partner).
Methods Network-based mathematical models of HIV type 1 (HIV-1) transmission dynamics among heterosexual couples were used to explore how changes to MMC alone and in combination with changes to concurrency impacted endemic HIV-1 prevalence and incidence. Starting from a base model parameterised from empirical data from West Africa, we simulated the prevalence of circumcision from 10% to 90% and concurrency was modelled at four discrete levels corresponding to values observed across SSA.
Results MMC and concurrency could contribute to the empirical variation in HIV-1 disease prevalence across SSA. Small reductions in concurrency resulted in large declines in HIV-1 prevalence. Scaling up circumcision in low-concurrency settings yields a greater relative benefit, but the absolute number of infections averted depends on both the circumcision coverage and baseline incidence. Epidemic extinction with this package will require substantial scale-up of MMC in low-concurrency settings.
Conclusions Dynamic sexual network structure should be considered in the design and targeting of MMC within combination HIV-1 prevention packages. Realistic levels of coverage for these packages within southern Africa could lead to a reduction of incidence to the low levels observed in western Africa, and possibly, epidemic extinction.
- MATHEMATICAL MODEL
- SEXUAL BEHAVIOUR
- SEXUAL NETWORKS
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Handling editor Jackie A Cassell
Twitter Follow Samuel Jenness at @SamuelJenness
Contributors SMJ conceived the idea for the study, and led the analysis and writing of the manuscript. SMG, MM and SC contributed to the concept development and writing of the manuscript. All authors have seen and approved the final version of the manuscript for publication.
Funding This work was supported in part by NIH Research Grants NICHD R00 HD057533, NICHD R01 HD68395; an NIH Training Grant NICHD T32 HD007543; and a UW Center for AIDS Research grant (P30 AI027757). Computing support was provided by a NICHD research infrastructure grant (R24 HD042828) to the UW Center for Studies in Demography & Ecology.
Competing interests None declared.
Ethics approval The institutional review boards of the University of Washington and University of Ghana approved all procedures (#41401).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Upon publication, the full software code base to run these models will be provided online at github.com.
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