Only a fraction of new HIV infections occur within identifiable stable discordant couples in sub-Saharan Africa

AIDS. 2013 Jan 14;27(2):251-60. doi: 10.1097/QAD.0b013e32835ad459.


Objective: To estimate the contribution of HIV-1 sero-conversions among stable HIV sero-discordant couples (SDCs) to total HIV population-level incidence in sub-Saharan Africa.

Design and methods: We constructed a mathematical model, grounded in nationally representative demographic and epidemiological data, that estimates the annual number of HIV-1 transmissions from the infected partners to the uninfected partners among established SDCs, and compares its value to an estimate for the overall HIV population-level incidence in 20 countries in sub-Saharan Africa. We defined identifiable HIV-1 transmissions among SDCs as those that a hypothetical screening and intervention program would have the potential to avert. Uncertainty and sensitivity analyses were incorporated to assess the robustness of the findings.

Results: Across the 20 countries, an average of 29% (range: 10-52%) of new HIV-1 infections occurred in which one partner in an identifiable SDC infected the other. The percentage of total HIV new infections in a country that occurred within such identifiable SDCs tended to be lower in countries with larger general population HIV epidemics. For most countries, HIV-1 incidence among SDCs is unlikely to exceed 50% of new HIV infections in the whole population.

Conclusion: Only a fraction of HIV-1 heterosexual transmissions occur within identifiable SDCs. Prevention within SDCs at scale requires a series of potentially challenging programmatic requirements to be met. Despite the importance of prevention programs aiming at protecting the sero-negative partner in an SDC, a wider strategy utilizing the full range of prevention modalities, which would limit the original generation of SDCs, is also needed.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa South of the Sahara / epidemiology
  • Female
  • HIV Infections / epidemiology*
  • HIV Infections / transmission
  • HIV Seropositivity / epidemiology*
  • HIV-1 / isolation & purification
  • Heterosexuality
  • Humans
  • Interpersonal Relations
  • Male
  • Models, Theoretical
  • Randomized Controlled Trials as Topic
  • Sexual Behavior*
  • Sexual Partners*