Background: Within an ongoing HIV/STD prevention project aimed at female sex workers (FSW) in Cotonou, Benin, we evaluated time trends in HIV and STD prevalences from 1993 to 1999.
Design: Three serial cross-sectional surveys were conducted in 1993 (n = 374), 1995–1996 (n = 365), and 1998–1999 (n = 591). A questionnaire was administered to the FSW and they were screened for HIV, syphilis, Neisseria gonorrhoeae, and Chlamydia trachomatis.
Results: The mean percentage of condom use with clients in the week preceding the interview increased from 62.2% in 1993 to 80.7% in 1998–1999 (P = 0.0001). The prevalence of all infections decreased significantly (all P < 0.02; chi-square for trend) over time: HIV from 53.3% in 1993 to 40.6% in 1998–1999; syphilis from 8.9 to 1.5%; gonorrhoea from 43.2 to 20.5%; and chlamydia from 9.4 to 5.1%. However, the mean age of FSW decreased from 31.0 to 28.4 years between 1993 and 1998–1999. Moreover, the country of origin of these women changed dramatically over time: the proportion of Ghanaian women decreased from 66.3% in 1993 to 21.6% in 1998–1999 when the predominant group became Nigerian (38.0%). When controlling for age and country of origin, HIV prevalence was stable over time (P = 0.71), whereas the downward trend remained significant for syphilis and gonorrhoea (both P < 0.001), and was present but not significant for chlamydia (P = 0.13).
Conclusion: These data suggest that the time trends in HIV and STD prevalences are partly due to the changing sex work milieu, but that the intervention also had an impact. Prevention programmes aimed at FSW should be highly prioritized.
From the aEpidemiology Research Group, Centre Hospitalier Affilié Universitaire de Québec (CHA) and Université Laval, Québec, Canada; bHéma-Québec, Montréal, Canada; cProjet Sida-2, Bénin; dDepartment of Social Science and Medicine, Imperial College School of Medicine, University of London, London, UK; eProgramme National de Lutte Contre le Sida et les MST, Cotonou, Bénin; and fLaboratoire de Santé Publique du Québec, Institut National de Santé Publique du Québec, Ste-Anne de Bellevue, Canada.
Correspondence to: Michel Alary, MD, PhD, Groupe de Recherche en Épidémiologie, Hôpital du Saint-Sacrement du CHA 1050, Chemin Sainte Foy, Québec, Québec G1S 4L8, Canada. Tel: +1 418 682 7387; fax: +1 418 682 7949; e-mail: email@example.com
Received: 18 June 2001;
revised: 20 September 2001; accepted: 26 September 2001.
Sponsorship: This study was funded in part by the Canadian International Development Agency through its West African AIDS Project executed by the Centre de Coopération Internationale en Santé et Développement Inc. (Québec, Canada). Additional funding was provided by AUPELF-UREF and by the Global Programme on AIDS of WHO. Michel Alary is the recipient of a research scholarship from the Fonds de la Recherche en Santé du Québec (970097). Léonard Mukenge-Tshibaka was the recipient of a PhD training award from the International Development Research Centre, Ottawa, Canada.