The ambitious 95-95-95 strategy was announced by UNAIDS in 2014, aiming to end the AIDS epidemic by 2030 by achieving 95% diagnosed among all people living with HIV (PLHIV), 95% on antiretroviral therapy (ART) among diagnosed, and 95% virally suppressed (VS) among treated. An intermediate goal of 90-90-90 was set for 2020. These targets have been adopted by many countries implying that treatment should be prioritized in resource allocation. We estimate the expected reduction in HIV incidence if the UNAIDS targets are met in South Africa by 2030 reaching different PLHIV groups by sexual risk behavior.
A risk equation model was used to simulate annual HIV incidence by tracking the transmission from PLHIV assuming 30% of them engaged in high-risk behavior (more frequent sex with multiple partners). Two baseline scenarios with different risk group coverage were parameterized with the HIV prevalence and 85-58-76 treatment cascade (i.e. 37% viral suppression of PLHIV), estimated in 2015 in South Africa, and calibrated to the 2015 HIV incidence among adult population (15-49 years). They were compared to scenarios in which UNAIDS targets are achieved and newly diagnosed, treated and virally suppressed PLHIV were: i) proportionally distributed between risk groups (proportional); ii) predominately recruited from the high-risk group (optimistic) and iii) predominately recruited from the low-risk group (pessimistic) with stable HIV prevalence up to 2030.
Annual HIV incidence was estimated 1.05% – 1.31% in 2015 depending on how treatment coverage was distributed between risk groups (see figure). Reaching the 90-90-90 target by 2030, resulting in 73% overall VS, may reduce annual HIV incidence to 0.29% if the cascade is predominately improved through recruitment from the high-risk group or to 0.74% if the cascade is improved with low-risk PLHIV. Reaching the 95-95-95 target, resulting in 86% overall VS, may result in 0.15% and 0.39% annual HIV incidence if the cascade is improved with high-risk and low-risk PLHIV, respectively. The HIV incidence projections in all scenarios remain above the elimination threshold of 0.1% (1 infection/1000 person-years).
Reaching UNAIDS treatment cascade targets does not equate the end of the HIV epidemic in South Africa. Expected HIV incidence strongly depend on the risk heterogeneity and the ART and VS coverage achieved among high-risk PLHIV. Scale-up of other HIV prevention tools is needed to bridge the gap to AIDS elimination.