Elimination of HIV in South Africa through Expanded Access to Antiretroviral Therapy: A Model Comparison Study

Hontelez, Jan A. C.; Lurie, Mark N.; Bärnighausen, Till; Bakker, Roel; Baltussen, Rob; Tanser, Frank; Hallett, Timothy B.; Newell, Marie‐Louise; Vlas, Sake J. de

doi:10.1371/journal.pmed.1001534

Cited by 125 publications

(88 citation statements)

References 73 publications

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“…Two behavioral parameters-the rate of transition from higher-to lower-risk groups and the population-level reduction in unprotected contact rate over time-were particularly important for simulating the observed prevalence trend in many different ways, as well as determining the intervention impact. There is evidence that reductions in risk have contributed to changes in HIV both in South Africa (8,33) and elsewhere (32,44,45). The value of R 0 during the intervention period was much more predictive of the reduction in incidence than R 0 at the start of the epidemic (Fig.…”

Section: Discussionmentioning

confidence: 96%

Why the proportion of transmission during early-stage HIV infection does not predict the long-term impact of treatment on HIV incidence

Eaton

Hallett

2014

Proc. Natl. Acad. Sci. U.S.A.

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Antiretroviral therapy (ART) reduces the infectiousness of HIVinfected persons, but only after testing, linkage to care, and successful viral suppression. Thus, a large proportion of HIV transmission during a period of high infectiousness in the first few months after infection ("early transmission") is perceived as a threat to the impact of HIV "treatment-as-prevention" strategies. We created a mathematical model of a heterosexual HIV epidemic to investigate how the proportion of early transmission affects the impact of ART on reducing HIV incidence. The model includes stages of HIV infection, flexible sexual mixing, and changes in risk behavior over the epidemic. The model was calibrated to HIV prevalence data from South Africa using a Bayesian framework. Immediately after ART was introduced, more early transmission was associated with a smaller reduction in HIV incidence rate-consistent with the concern that a large amount of early transmission reduces the impact of treatment on incidence. However, the proportion of early transmission was not strongly related to the long-term reduction in incidence. This was because more early transmission resulted in a shorter generation time, in which case lower values for the basic reproductive number (R 0 ) are consistent with observed epidemic growth, and R 0 was negatively correlated with long-term intervention impact. The fraction of early transmission depends on biological factors, behavioral patterns, and epidemic stage and alone does not predict long-term intervention impacts. However, early transmission may be an important determinant in the outcome of short-term trials and evaluation of programs.HIV incidence | antiretroviral therapy | early infection | HIV prevention intervention | mathematical model R ecent studies have confirmed that effective antiretroviral therapy (ART) reduces the transmission of HIV among stable heterosexual couples (1-3). This finding has generated interest in understanding the population-level impact of HIV treatment on reducing the rate of new HIV infections in generalized epidemic settings (4). Research, including mathematical modeling (5-10), implementation research (11), and major randomized controlled trials (12)(13)(14), are focused on how ART provision might be expanded strategically to maximize its public health benefits (15, 16).One concern is that if a large fraction of HIV transmission occurs shortly after a person becomes infected, before the person can be diagnosed and initiated on ART, this will limit the potential impact of HIV treatment on reducing HIV incidence (9,17,18). Data suggest that persons are more infectious during a short period of "early infection" after becoming infected with HIV (19-22), although there is debate about the extent, duration, and determinants of elevated infectiousness (18, 23). The amount of transmission that occurs also will depend on patterns of sexual behavior and sexual networks (17,(24)(25)(26)(27). There have been estimates for the contribution of early infection to transmission from math...

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Section: Discussionmentioning

confidence: 96%

Why the proportion of transmission during early-stage HIV infection does not predict the long-term impact of treatment on HIV incidence

Eaton

Hallett

2014

Proc. Natl. Acad. Sci. U.S.A.

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“…Previous modeling studies on the use of TasP have pointed to the optimistic prospect for complete elimination of the sexual spread of HIV [5,33]. We conclude that among IDU however, only unrealistically high uptake rates from very early after infection would allow cART provision by itself to eliminate HIV.…”

Section: Discussionmentioning

confidence: 74%

Treatment as prevention among injecting drug users; extrapolating from the Amsterdam cohort study

Vos

Prins

Coutinho

et al. 2014

Aids

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“…In 2004, the context began to radically shift with the introduction of ART in South Africa, but to date universal testing and treatment (UTT) has not been achieved (Hontelez et al 2013). While some argue that PEPFAR did produce significant results (Walensky and also prompted multiple controversies.…”

Section: Abc Hiv and History In South Africa Todaymentioning

confidence: 99%

Reducing the overall HIV-burden in South Africa: is ‘reviving ABC’ an appropriate fit for a complex, adaptive epidemiological HIV landscape?

Burman

Aphane

Delobelle

2015

African Journal of AIDS Research

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This article questions the recommendations to 'revive ABC (abstain, be faithful, condomise)' as a mechanism to 'educate' people in South Africa about HIV prevention as the South African National HIV Prevalence, Incidence and Behaviour Survey, 2012, suggests. We argue that ABC was designed as a response to a particular context which has now radically changed. In South Africa the contemporary context reflects the mass roll-out of antiretroviral treatment; significant bio-medical knowledge gains; a generalised population affected by HIV that has made sense of and embodied those diverse experiences; and a government committed to confronting the epidemic. We suggest that the situation can now be plausibly conceptualised as a complex, adaptive epidemiological landscape that could benefit from an expansion of the existing, 'descriptive' prevention paradigm towards strategies that focus on the dynamics of transmission. We argue for this shift by proposing a theoretical framework based on complexity theory and pattern management. We interrogate one educational prevention heuristic that emphasises the importance of risk-reduction through the lens of transmission, called A-3B-4C-T. We argue that this type of approach provides expansive opportunities for people to engage with the epidemic in contextualised, innovative ways that supersede the opportunities afforded by ABC. We then suggest that framing the prevention imperative through the lens of 'dynamic prevention' at scale opens more immediate opportunities, as well as developing a future-oriented mind-set, than the 'descriptive prevention' parameters can facilitate. The parameters of the 'descriptive prevention' paradigm, that maintain - and partially reinforce - the presence of ABC, do not have the flexibility required to develop the armamentarium of tools required to contribute to the management of a complex epidemiological landscape. Uncritically adhering to both the 'descriptive paradigm', and ABC, represents an historically dislocated form of prevention - with restrictive options for reducing the overall burden of HIV-related challenges in South Africa.

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Elimination of HIV in South Africa through Expanded Access to Antiretroviral Therapy: A Model Comparison Study

Abstract: Using nine structurally different models, Jan Hontelez and colleagues investigate timeframes for HIV elimination in South Africa using a universal test and treat strategy. Please see later in the article for the Editors' Summary

Cited by 125 publications

References 73 publications

Why the proportion of transmission during early-stage HIV infection does not predict the long-term impact of treatment on HIV incidence

Why the proportion of transmission during early-stage HIV infection does not predict the long-term impact of treatment on HIV incidence

Treatment as prevention among injecting drug users; extrapolating from the Amsterdam cohort study

Reducing the overall HIV-burden in South Africa: is ‘reviving ABC’ an appropriate fit for a complex, adaptive epidemiological HIV landscape?

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