Home HIV testing and counseling for reducing HIV incidence in a generalized epidemic setting: a mathematical modeling analysis

BACKGROUND: Home HIV testing and counseling (HTC) achieves high levels of HIV testing and linkage to care. Periodic home HTC, particularly targeted to those with high HIV viral load, may facilitate expanding antiretroviral therapy (ART) coverage. We used a mathematical model to assess the impact of periodic home HTC programs on HIV incidence in KwaZulu-Natal, South Africa. METHODS: We developed a dynamic HIV transmission model with parameters, primary cost data, and measures of viral suppression collected from a prospective study of home HTC in KwaZulu-Natal. We assumed five-yearly home HTC with ART initiation for persons with CD4≤350 cells/µL. For individuals with CD4>350 cells/µL, we compared increasing ART coverage for those who have CD4 counts 350–500 cells/µL with those who have viral loads >10,000 copies/mL. FINDINGS: Maintaining the current level of 36% viral suppression among HIV-positive persons, HIV incidence decreases by 34% over 10 years. Five-yearly home HTC and linkage to care with ART initiation at CD4≤350 cells/µL reduces HIV incidence by 57% over 10 years. Expanding ART to persons with CD4>350 cells/µL who also have VL>10,000 copies/mL decreases HIV incidence by 68%, and was the most cost-effective strategy for preventing HIV infections at $2,960 per infection averted. Expanding ART eligibility to persons with CD4 350–500 cells/µL is cost-effective at $900 per QALY gained. Following health economic guidelines, expanding ART use to those who have VL>10,000 copies/mL among those with CD4>350 cells/µL was cost-effective to reduce HIV-related morbidity. INTERPRETATION: In KwaZulu-Natal, five-yearly province-wide home HTC can cost-effectively increase ART coverage and reduce HIV burden. ART initiation criteria based on VL>10,000 copies/mL for those with CD4>350 cells/µL is also an efficient strategy for HIV prevention.