Progress towards the 2020 targets for HIV diagnosis and antiretroviral treatment in South Africa

Introduction

Expanded access to HIV testing and antiretroviral treatment (ART) is critical both to reducing levels of AIDS mortality and to reducing HIV incidence, at a population level. This is therefore the focus of the UNAIDS 2020 targets, which aim to achieve a 90% rate of diagnosis in people living with HIV, a 90% rate of ART coverage in HIV-diagnosed individuals and a 90% rate of virological suppression in patients on ART.¹

However, few African countries have been able to report progress towards these ‘90-90-90’ targets.^2,3 Most household surveys conducted in African countries do not include questions about whether HIV-positive individuals know they are HIV-positive, which prevents estimation of the fraction of HIV-positive individuals who have been diagnosed. In addition, most African countries have only recently introduced virological monitoring of ART patients, and there is thus limited ability to report on progress towards the last 90% target. This means that the few African studies published to date have relied on special surveys for tracking progress towards the 90-90-90 targets,^4,5 and almost none have made use of routine monitoring systems.⁶

In South Africa, it has been shown that by triangulating HIV testing data from a number of sources, it is possible to arrive at estimates of the fraction of HIV-positive adults who have been diagnosed positive.⁷ The South African ART programme has also recommended virological monitoring since its inception,⁸ and systems for reporting rates of virological suppression have been established.^9,10 South Africa is therefore well placed to track its progress towards the 90-90-90 targets. This article aims to estimate progress towards the targets in the period up to 2015, at national and provincial levels.

Methods

Progress towards the 90-90-90 targets is estimated using the Thembisa model, a combined demographic and HIV model of the South African population. HIV disease progression prior to ART initiation is modelled using a staged model of CD4 decline, with rates of transition between CD4 stages set so that the modelled estimates of the fraction of HIV-positive adults in different CD4 stages match those observed in South African surveys, and HIV mortality assumptions by CD4 stage being set so that the model matches observed trends in mortality by age.¹¹

As described previously, the model...