Portfolios of biomedical HIV interventions in South Africa: a cost-effectiveness analysis

Abstract

Background: Recent clinical trials of male circumcision, oral pre-exposure prophylaxis (PrEP), and a vaginal microbicide gel have shown partial effectiveness at reducing HIV transmission, stimulating interest in implementing portfolios of biomedical prevention programs.

Objective: To evaluate the effectiveness and cost-effectiveness of combination biomedical HIV prevention and treatment scale-up in South Africa, given uncertainty in program effectiveness.

Design: Dynamic HIV transmission and disease progression model with Monte Carlo simulation and cost-effectiveness analysis.

Participants: Men and women aged 15 to 49 years in South Africa.

Interventions: HIV screening and counseling, antiretroviral therapy (ART), male circumcision, PrEP, microbicide, and select combinations.

Main measures: HIV incidence, prevalence, discounted costs, discounted quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios.

Key results: Providing half of all uninfected persons with PrEP averts 28 % of future HIV infections for $9,000/QALY gained, but the affordability of such a program is questionable. Given limited resources, annual HIV screening and ART utilization by 75 % of eligible infected persons could avert one-third of new HIV infections, for approximately $1,000/QALY gained. Male circumcision is more cost-effective, but disproportionately benefits men. A comprehensive portfolio of expanded screening, ART, male circumcision, microbicides, and PrEP could avert 62 % of new HIV infections, reducing HIV prevalence from a projected 14 % to 10 % after 10 years. This strategy doubles treatment initiation and adds 31 million QALYs to the population. Despite uncertainty in program effectiveness, a comprehensive portfolio costs less than $10,000/QALY gained in 33 % of simulation iterations and less than $30,000/QALY gained in 90 % of iterations, assuming an annual microbicide cost of $100.

Conclusions: A portfolio of modestly-effective biomedical HIV prevention programs, including male circumcision, vaginal microbicides, and oral PrEP, could substantially reduce HIV incidence and prevalence in South Africa and be likely cost-effective. Given limited resources, PrEP is the least cost-effective intervention of those considered.

Figure 1.

HIV prevalence over 10 years. Projected HIV prevalence in men (dashed lines) and women (solid lines) under the status quo (black circles); annual HIV screening and 75 % ART utilization (red triangles); 75 % male circumcision coverage within 5 years, 50 % microbicide utilization, and 50 % PrEP utilization (blue squares); or a combination portfolio of all 5 programs (cyan diamonds). ART = antiretroviral therapy; PrEP = oral pre-exposure prophylaxis.

Figure 2.

Cost-effectiveness analysis. Discounted costs and discounted QALYs over 10 years are shown for select portfolios: 75 % ART utilization; annual HIV screening; 75 % male circumcision coverage within 5 years; 50 % microbicide utilization; 50 % PrEP utilization; or select combinations of all five programs. The solid line corresponds to the cost-effectiveness frontier (strategies that are most economically efficient) with the incremental cost-effectiveness ratios given. QALY = quality-adjusted life year; ART = antiretroviral therapy; PrEP = oral pre-exposure prophylaxis.

Figure 3.

Probabilistic sensitivity analysis. Frequency distribution showing the projected number of HIV infections over 10 years (left charts) and overall HIV prevalence after 10 years (right charts) under the status quo (top, black) or combination portfolio of all five programs (bottom, cyan), based on a Monte Carlo simulation with 1,000 iterations. Each bar shows the relative frequency of projected HIV infections or HIV prevalence.

Figure 4.

Probabilistic cost-effectiveness analysis. a Discounted costs and discounted QALYs over 10 years are shown for select portfolios: status quo (black dots); annual HIV screening and 75 % ART utilization (red triangles); or a combination portfolio of annual HIV screening, 75 % ART utilization, 75 % male circumcision coverage within 5 years, 50 % microbicide utilization, and 50 % PrEP utilization (cyan diamonds). b Cumulative probability distributions for the cost-effectiveness of annual HIV screening and 75 % ART utilization versus the status quo (red line); or a combination portfolio of annual HIV screening, 75 % ART utilization, 75 % male circumcision coverage within 5 years, 50 % microbicide utilization, and 50 % PrEP utilization versus screening and ART only (cyan line). The graph shows the probability that the select portfolio has a cost-effectiveness ratio less than the value on the x-axis, given a Monte Carlo simulation with 1,000 iterations. QALY = quality-adjusted life year; ART = antiretroviral therapy; PrEP = oral pre-exposure prophylaxis.