Sources of HIV incidence among stable couples in sub‐Saharan Africa

Hiam Chemaitelly,Susanne F Awad,James D Shelton,Laith J Abu‐Raddad

doi:10.7448/ias.17.1.18765

Abstract

IntroductionThe recent availability of efficacious prevention interventions among stable couples offers new opportunities for reducing HIV incidence in sub-Saharan Africa. Understanding the dynamics of HIV incidence among stable couples is critical to inform HIV prevention strategy across sub-Saharan Africa.MethodsWe quantified the sources of HIV incidence arising among stable couples in sub-Saharan Africa using a cohort-type mathematical model parameterized by nationally representative data. Uncertainty and sensitivity analyses were incorporated.ResultsHIV incidence arising among stable concordant HIV-negative couples contribute each year, on average, 29.4% of total HIV incidence; of those, 22.5% (range: 11.1%–39.8%) are infections acquired by one of the partners from sources external to the couple, less than 1% are infections acquired by both partners from external sources within a year and 6.8% (range: 3.6%–11.6%) are transmissions to the uninfected partner in the couple in less than a year after the other partner acquired the infection from an external source. The mean contribution of stable HIV sero-discordant couples to total HIV incidence is 30.4%, with most of those, 29.7% (range: 9.1%–47.9%), being due to HIV transmissions from the infected to the uninfected partner within the couple. The remaining incidence, 40.2% (range: 23.7%–64.6%), occurs among persons not in stable couples.ConclusionsClose to two-thirds of total HIV incidence in sub-Saharan Africa occur among stable couples; however, only half of this incidence is attributed to HIV transmissions from the infected to the uninfected partner in the couple. The remaining incidence is acquired through extra-partner sex. Substantial reductions in HIV incidence can be achieved only through a prevention approach that targets all modes of HIV exposure among stable couples and among individuals not in stable couples.

Highlights

The recent availability of efficacious prevention interventions among stable couples offers new opportunities for reducing HIV incidence in sub-Saharan Africa
The average contribution of both partners acquiring the infection from an external source (SCNCext)2), within the same year, is less than 1% across the countries (Figure 3B)
The contribution attributed to the index partner transmitting the infection to the uninfected partner shortly after HIV acquisition from an external source (SCNCext'int), that is within the same year of observation, is on average 6.8% across countries (Figure 3C)

Summary

Introduction

The mean contribution of stable HIV sero-discordant couples to total HIV incidence is 30.4%, with most of those, 29.7% (range: 9.1%Á47.9%), being due to HIV transmissions from the infected to the uninfected partner within the couple. Conclusions: Close to two-thirds of total HIV incidence in sub-Saharan Africa occur among stable couples; only half of this incidence is attributed to HIV transmissions from the infected to the uninfected partner in the couple. Recent randomized clinical trials have demonstrated the potential for averting much of the HIV heterosexual transmission among stable HIV serodiscordant couples (SDCs) using highly efficacious HIV prevention interventions such as antiretroviral therapy (ART) [6Á9]. We estimate the contribution of HIV incidence among SDCs where the uninfected partner acquires the infection from a source external to the couple (SDCext). We update the results of our earlier work on SDCs [13,14] through the use of recently available survey data, in addition to including countries that were not covered earlier, and the use of a more elaborate mathematical modeling framework for generating these estimates

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Results

Conclusion