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The combined impact of male circumcision, condom use and HAART coverage on the HIV-1 epidemic in South Africa: a mathematical model
Presented by Viviane Dias Lima (Canada).
V. Lima1, A. Anema1, R. Wood2, D. Moore1, R. Harrigan1, E. Mills1, R. Hogg1, J. Montaner1
1British Columbia Centre for Excellence in HIV/AIDS, Vancouver, Canada, 2Desmond Tutu HIV Foundation, Cape Town, South Africa
Background: Mathematical modeling is essential to determining population-level risks and outcomes of HIV/AIDS. In South Africa, HIV is simultaneously driven by transmission from mother-to-child, heterosexual contacts, men-who-have-sex with men (MSM), injection drug users (IDU), and nosocomial sources. Given the multiplicity of transmission sources, there is a need to understand which prevention strategies will most effectively mitigate the spread of the epidemic at the population level. This abstract presents preliminary results from a large simulation study to estimate the concurrent impact of different prevention strategies on the HIV epidemic in South Africa.
Methods: We built dynamic mathematical model to simultaneously access the impact of varying scenarios of circumcision (51% [base], 75%, 90%), condom use (14% [base], 50%, 80%) and HAART coverage (21% [base], 50%, 80%) on the heterosexual male population (15 - 49 years). The model considers a CD4 cell count ≤200 cells/mm3 to be the key eligibility criterion for starting therapy. The model was calibrated using published prevalence and mortality (all-cause) data from 2003 to 2008 and run until 2025. This model was implemented in Berkeley Madonna Inc. version 8.3.11.
Results: Our model predicted that increased condom use and HAART coverage (alone or in combination) were the most effective interventions to reduce new infections (range 64%-95% reduction) and deaths (range 10%-34% reduction) (Figure). Circumcision had a limited impact in reducing both new infections (range 3%-13% reduction) and deaths (range 2%-4% reduction), and its impact was overshadowed when combined with the other interventions.
Conclusions: Our results show that giving priority to increased HAART coverage (within current guidelines - CD4 cell count at HAART initiation ≤200 cells/mm3) and condom use, both previously shown to be cost-effective even in resource-limited settings, can have an immediate large effect in curbing the HIV epidemic in South Africa.
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