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AIDS. 2018 Mar 13;32(5):635-643. doi: 10.1097/QAD.0000000000001737.

Impact of early antiretroviral therapy eligibility on HIV acquisition: household-level evidence from rural South Africa.

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Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
Francis I. Proctor Foundation, University of California, San Francisco, California.
Department of Global Health, Boston University School of Public Health, Boston, Massachusetts, USA.
Africa Health Research Institute, KwaZulu-Natal, South Africa.
Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA.
Institute for Global Health, University College London.
Faculty of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.
Department of Biostatistics, Harvard T.H. Chan School of Public Health.
The Fenway Institute, Fenway Community Health, Boston, Massachusetts.
Departments of Behavioral and Social Sciences & Epidemiology, The Institute for Community Health Promotion, Brown University School of Public Health, Providence, Rhode Island.
Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
Division of Infection and Immunity, University College London, London, UK.
Research Department of Infection and Population Health, Centre for Sexual Health, University College London, London, UK.
Heidelberg Institute of Public Health, University of Heidelberg, Heidelberg, Germany.



We investigate the effect of immediate antiretroviral therapy (ART) eligibility on HIV incidence among HIV-uninfected household members.


Regression discontinuity study arising from a population-based cohort.


Household members of patients seeking care at the Hlabisa HIV Treatment and Care Programme in rural KwaZulu-Natal South Africa between January 2007 and August 2011 with CD4 cell counts up to 350 cells/μl were eligible for inclusion if they had at least two HIV tests and were HIV-uninfected at the time the index patient linked to care (N = 4115). Regression discontinuity was used to assess the intention-to-treat effect of immediate versus delayed ART eligibility on HIV incidence among household members. Exploiting the CD4 cell count-based threshold rule for ART initiation (CD4 < 200 cells/μl until August 2011), we used Cox proportional hazards models to compare outcomes for household members of patients who presented for care with CD4 cell counts just above versus just below the ART initiation threshold.


Characteristics of household members of index patients initiating HIV care were balanced between those with an index patient immediately eligible for ART (N = 2489) versus delayed for ART (N = 1626). There were 337 incident HIV infections among household members, corresponding to an HIV incidence of 2.4 infections per 100 person-years (95% confidence interval 2.5-3.1). Immediate eligibility for treatment reduced HIV incidence in households by 47% in our optimal estimate (hazard ratio = 0.53, 95% confidence interval 0.30-0.96), and by 32-60% in alternate specifications of the model.


Immediate eligibility of ART led to substantial reductions in household-level HIV incidence.

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