title: Sources of HIV incidence among stable couples in sub-Saharan Africa.
abstract: BACKGROUND
  The 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.
  
  
  METHODS
  We 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.
  
  
  RESULTS
  HIV 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.
  
  
  CONCLUSIONS
  Close 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.
authors.affiliation: Infectious Disease Epidemiology Group, Weill Cornell Medical College in Qatar, Cornell University, Qatar Foundation, Education City, Doha, Qatar.
authors.forename: Hiam
authors.initials: H
authors.lastname: Chemaitelly
authors.affiliation: Infectious Disease Epidemiology Group, Weill Cornell Medical College in Qatar, Cornell University, Qatar Foundation, Education City, Doha, Qatar.
authors.forename: Susanne F
authors.initials: SF
authors.lastname: Awad
authors.affiliation: Bureau for Global Health, United States Agency for International Development, Washington, DC, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Shelton
authors.affiliation: Infectious Disease Epidemiology Group, Weill Cornell Medical College in Qatar, Cornell University, Qatar Foundation, Education City, Doha, Qatar; Department of Healthcare Policy and Research, Weill Cornell Medical College, Cornell University, New York, USA; Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, DC, USA; lja2002@qatar-med.cornell.edu.
authors.forename: Laith J
authors.initials: LJ
authors.lastname: Abu-Raddad
mesh_terms: D017954:Africa South of the Sahara / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000209:etiology*; D018023:HIV Seronegativity; D006679:HIV Seropositivity / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008962:Models, Theoretical; D018454:Spouses / Q000706:statistics & numerical data
keywords: HIV incidence; Sub-Saharan Africa; demographic and health surveys; mathematical model; sources of infection; stable couples