Early ART or PrEP? A Comparative Analysis of Effectiveness and Cost of HIV Prevention Through Antiretroviral Drugs

Background:While behavior changes remains at the center of HIV prevention strategies, results from clinical trials using antiretroviral drugs for prevention suggest that these approaches hold tremendous promise.  Pre-exposure prophylaxis (PrEP) of HIV-uninfected individuals and early antiretroviral therapy (ART) of people with HIV infection are two new strategies to prevent acquiring or transmitting HIV.

Methods: To examine the relative benefits and risks of PrEP (using tenofovir [TDF] or TDF-emtricitabine [TDF-FTC]) and early ART, we conducted a systematic review and modeled the impact of each strategy individually and in combination. We used data from our meta-analysis to build seven separate mathematical models to study the effect of early ART, TDF-based PrEP, TDF-FTC-based PrEP, TDF PrEP in combination with early ART, TDF-FTC PrEP in combination with early ART, delayed ART, and placebo in a theoretical African heterosexual population of 10,000 serodiscordant couples each. We calculated number-needed-to-treat (NNT) and the cost-effectiveness of each strategy using data from the literature.

Results:Transmission rates for TDF and TDF-FTC PrEP were 0.65 and 0.67 per person-year respectively. Using placebo as the baseline, the NNT for early ART, TDF PrEP, and TDF-FTC PrEP were 18, 22, and 22 respectively. Although the models show lower transmissions for early ART than for PrEP, ART is more expensive.  Over a theoretical 3-year period when the cost of testing and counseling is not included, early ART costs approximately $32,800 to prevent one additional infection while PrEP varies from $9,030 to $9,150.  The NNT for combination early ART and PrEP is 15, but it costs more than $35,400 to prevent one additional infection.

Conclusions: Both PrEP and early ART are effective for preventing HIV transmission with NNT ranging from 15 to 22. Additional analysis is required to ascertain the cost-benefit of these strategies both alone and in combination with HIV. Counseling and HIV testing and other complimentary behavioral and structural interventions are still essential.