Purpose: Although HIV testing and treatment have been scaled up in Africa, inadequate HIV testing rates, infrequent re-testing, inconsistent connection to care, and high rates of loss to follow-up pose substantial challenges. We examine factors that influence HIV outcomes due to testing and treatment in South Africa.
Method: We developed a stochastic simulation model of HIV disease and transmission calibrated to South Africa that compares the effectiveness of testing and treatment strategies. Risk of being in a sexual relationship with an infected partner was determined by age, number of partners, and HIV prevalence. Per-act transmission risk was determined by gender, circumcision status for males, and the partner’s viral load and disease state. We examined the importance of HIV testing rates, testing frequencies, the link between testing and treatment sites (connection to care), and rates of loss to follow-up. The primary outcomes of interest were life years gained, HIV infections averted over 10 years, and number of deaths from HIV.
Result: At the current pace of scale-up (status quo), HIV prevalence will decline from 18.2% to 17.3% over 10 years. Compared to the status quo, optimized care –universal testing, annual re-testing, full connection to care, no loss to follow-up, and early initiation of antiretroviral therapy – was associated with a gain of 1.2 life years per-person in the entire population, a 77% decrease in the number of new infections, and a 62% decrease in the number of deaths from HIV. Nearly half of the gain in life years was due to a 10% relative increase in population size that resulted from reducing mortality in adults of childbearing age. Gains in life expectancy compared to the status quo were 6.5 months with universal testing, 3.8 months with perfect connection to care, 3.1 months with eliminating loss to follow-up, and 0.1 months with annual re-testing. Full connection to care was the most effective strategy for reducing new infections, an 18.2% reduction compared to the status quo.
Conclusion: Optimizing HIV care could greatly reduce the burden of HIV in South Africa, but requires substantial improvements over the status quo. Among the interventions examined, universal testing provides the greatest health benefits. Without additional scale-up efforts, the burden of HIV in South Africa may not decrease substantially.
Candidate for the Lee B. Lusted Student Prize Competition