This article is based on the presentation given by John Hargrove at the NRF Science for Society Lecture entitled Ending HIV/AIDS in South Africa held on 1 December 2016 in Stellenbosch. He argues that the proactive use of ART (Treatment as Prevention or TasP) provides a powerful weapon for combatting the HIV epidemic, and that we also have the tools for monitoring and evaluating the progress of that programme. Mathematical modelling has played an important role, both in suggesting appropriate interventions, and in developing new monitoring methods, but we are still in for a long journey.
As coverage of paediatric ART increases and guidelines for ART initiation change, it will be necessary to determine how best to monitor ART. Routine monitoring of HIV viral load is common practice in ART programmes in high-income countries, but, in sub-Saharan Africa, most ART programmes rely on CD4 cell measurements or clinical monitoring to detect treatment failure. We conducted a computer simulation of HIV-positive children to predict the effect of different ART monitoring strategies.
A recent randomized controlled trial demonstrated that antiretroviral therapy (ART) prevents HIV transmission. In successfully treated patients the HI virus in the blood is suppressed to undetectable levels and therefore the probability of transmitting the virus is extremely low. This new finding must be incorporated into the evaluation of the advantages and disadvantages of different ART provision strategies. The optimal strategy for monitoring treatment response and detecting treatment failure – routine viral load monitoring (rVL) or CD4 cell counts or clinical symptoms – has been the subject of continuous debate. We suspected that rVL could potentially prevent HIV transmission by making it easier to detect treatment failure earlier. We developed a mathematical simulation model to estimate potential transmission from 1,000 patients treated with ART with either rVL or CD4 monitoring.