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Declines in HIV prevalence can be associated with changing sexual behaviour in Uganda, urban Kenya, Zimbabwe, and urban Haiti
  1. T B Hallett1,
  2. J Aberle-Grasse2,
  3. G Bello3,
  4. L-M Boulos4,
  5. M P A Cayemittes5,
  6. B Cheluget6,
  7. J Chipeta7,
  8. R Dorrington8,
  9. S Dube9,
  10. A K Ekra10,
  11. J M Garcia-Calleja11,
  12. G P Garnett1,
  13. S Greby12,
  14. S Gregson13,
  15. J T Grove14,
  16. S Hader12,
  17. J Hanson12,
  18. W Hladik15,
  19. S Ismail16,
  20. S Kassim15,
  21. W Kirungi17,
  22. L Kouassi18,
  23. A Mahomva19,
  24. L Marum20,
  25. C Maurice10,
  26. M Nolan14,
  27. T Rehle21,
  28. J Stover22,
  29. N Walker23
  1. 1Imperial College, London, UK
  2. 2Centers for Disease Control and Prevention, Global AIDS Program, Malawi
  3. 3Ministry of Health, Community Health Sciences Unit, Malawi
  4. 4CERA, Haiti
  5. 5Institut Haitien de l’Enfance, Haiti
  6. 6National AIDS Control Council, Kenya
  7. 7National AIDS Commission, Lilongwe, Malawi
  8. 8Centre for Actuarial Research, Cape Town, South Africa
  9. 9Department of Infectious Disease Epidemiology, Imperial College, London, UK
  10. 10Projet RETRO-CI, Abidjan, Cote d’Ivoire
  11. 11World Health Organization, Geneva, Switzerland
  12. 12US Centers for Disease Control and Prevention, Rwanda, Zimbabwe
  13. 13Imperial College London and Biomedical Research and Training Institute, Harare, Zimbabwe
  14. 14Projet RETRO-CI, Centers for Disease Control and Prevention, Cote d’Ivoire
  15. 15Centers for Disease Control and Prevention, Atlanta, GA, USA
  16. 16Centers for Disease Control and Prevention, Ethiopia
  17. 17Ministry of Health, Kampala, Uganda
  18. 18National Institute of Statistics, Cote d’Ivoire
  19. 19Ministry of Health and Child Welfare, Rwanda, Zimbabwe
  20. 20Centers for Disease Control and Prevention, Kenya
  21. 21Human Sciences Research Council, Cape Town, South Africa
  22. 22Futures Group, Glastonbury, CT, USA
  23. 23UNICEF, USA
  1. Correspondence to:
 T B Hallett
 Department of Infectious Disease Epidemiology, Imperial College, Norfolk Place, London W2 1PG, UK; timothy.hallett{at}


Objective: To determine whether observed changes in HIV prevalence in countries with generalised HIV epidemics are associated with changes in sexual risk behaviour.

Methods: A mathematical model was developed to explore the relation between prevalence recorded at antenatal clinics (ANCs) and the pattern of incidence of infection throughout the population. To create a null model a range of assumptions about sexual behaviour, natural history of infection, and sampling biases in ANC populations were explored to determine which factors maximised declines in prevalence in the absence of behaviour change. Modelled prevalence, where possible based on locally collected behavioural data, was compared with the observed prevalence data in urban Haiti, urban Kenya, urban Cote d’Ivoire, Malawi, Zimbabwe, Rwanda, Uganda, and urban Ethiopia.

Results: Recent downturns in prevalence observed in urban Kenya, Zimbabwe, and urban Haiti, like Uganda before them, could only be replicated in the model through reductions in risk associated with changes in behaviour. In contrast, prevalence trends in urban Cote d’Ivoire, Malawi, urban Ethiopia, and Rwanda show no signs of changed sexual behaviour.

Conclusions: Changes in patterns of HIV prevalence in urban Kenya, Zimbabwe, and urban Haiti are quite recent and caution is required because of doubts over the accuracy and representativeness of these estimates. Nonetheless, the observed changes are consistent with behaviour change and not the natural course of the HIV epidemic.

  • AIDS, acquired immune deficiency syndrome
  • ANC, antenatal clinic
  • HIV, human immunodeficiency virus
  • epidemiology
  • HIV
  • prevalence

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  • TBH, SG and GPG thank The Wellcome Trust and UNAIDS for Grant support. GPG thanks the MRC for grant support.

  • Competing interests: none declared

  • The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.

  • Edited by N Walker, H Ward and R Miller