HIV treatment-as-prevention research: authors' reply

Opportunities and Challenges in HIV Treatment as Prevention Research: Results from the ANRS 12249 Cluster-Randomized Trial and Associated Population Cohort

PURPOSE OF REVIEW

The ANRS 12249 treatment as prevention (TasP) trial investigated the impact of a universal test and treat (UTT) approach on reducing HIV incidence in one of the regions of the world most severely affected by the HIV epidemic-KwaZulu-Natal, South Africa. We summarize key findings from this trial as well as recent findings from controlled studies conducted in the linked population cohort quantifying the long-term effects of expanding ART on directly measured HIV incidence (2004-2017).

RECENT FINDINGS

The ANRS TasP trial did not-and could not-demonstrate a reduction in HIV incidence, because the offer of UTT in the intervention communities did not increase ART coverage and population viral suppression compared to the standard of care in the control communities. Ten controlled studies from the linked population cohort-including several quasi-experimental study designs-exploit heterogeneity in ART exposure to show a consistent and substantial impact of expanding provision of ART and population viral suppression on reduction in HIV incidence at the couple, household, community, and population levels. In this setting, all of the evidence from large, population-based studies (inclusive of the ANRS TasP trial) is remarkably coherent and consistent-i.e., higher ART coverage and population viral suppression were repeatedly associated with clear, measurable decreases in HIV incidence. Thus, the expanded provision of ART has plausibly contributed in a major way toward the dramatic 43% decline in population-level HIV incidence in this typical rural African population. The outcome of the ANRS TasP trial constitutes a powerful null finding with important insights for overcoming implementation challenges in the population delivery of ART. This finding does not imply lack of ART effectiveness in blocking onward transmission of HIV nor its inability to reduce HIV incidence. Rather, it demonstrates that large increases in ART coverage over current levels will require health systems innovations to attract people living with HIV in early stages of the disease to participate in HIV treatment. Such innovations and new approaches are required for the true potential of UTT to be realized.

Comparative assessment of five trials of universal HIV testing and treatment in sub-Saharan Africa

Design

Universal voluntary HIV counselling and testing followed by prompt initiation of antiretroviral therapy (ART) for all those diagnosed HIV‐infected (universal test and treat, UTT) is now a global health standard. However, its population‐level impact, feasibility and cost remain unknown. Five community‐based trials have been implemented in sub‐Saharan Africa to measure the effects of various UTT strategies at population level: BCPP/YaTsie in Botswana, MaxART in Swaziland, HPTN 071 (PopART) in South Africa and Zambia, SEARCH in Uganda and Kenya and ANRS 12249 TasP in South Africa. This report describes and contrasts the contexts, research methodologies, intervention packages, themes explored, evolution of study designs and interventions related to each of these five UTT trials.

Methods

We conducted a comparative assessment of the five trials using data extracted from study protocols and collected during baseline studies, with additional input from study investigators. We organized differences and commonalities across the trials in five categories: trial contexts, research designs, intervention packages, trial themes and adaptations.

Results

All performed in the context of generalized HIV epidemics, the trials highly differ in their social, demographic, economic, political and health systems settings. They share the common aim of assessing the impact of UTT on the HIV epidemic but differ in methodological aspects such as study design and eligibility criteria for trial populations. In addition to universal ART initiation, the trials deliver a wide range of biomedical, behavioural and structural interventions as part of their UTT strategies. The five studies explore common issues, including the uptake rates of the trial services and individual health outcomes. All trials have adapted since their initiation to the evolving political, economic and public health contexts, including adopting the successive national recommendations for ART initiation.

Conclusions

We found substantial commonalities but also differences between the five UTT trials in their design, conduct and multidisciplinary outputs. As empirical literature on how UTT may improve efficiency and quality of HIV care at population level is still scarce, this article provides a foundation for more collaborative research on UTT and supports evidence‐based decision making for HIV care in country and internationally.