Positive impact of increases in condom use among female sex workers and clients in a medium HIV prevalence epidemic: modelling results from Project SIDA1/2/3 in Cotonou, Benin.

BACKGROUND: A comprehensive, HIV prevention programme (Projet Sida1/2/3) was implemented among female sex workers (FSWs) in Cotonou, Benin, in 1993 following which condom use among FSWs increased threefold between 1993 and 2008 while FSW HIV prevalence declined from 53.3% to 30.4%. OBJECTIVE: Estimate the potential impact of the intervention on HIV prevalence/incidence in FSWs, clients and the general population in Cotonou, Benin. METHODS AND FINDINGS: A transmission dynamics model parameterised with setting-specific bio-behavioural data was used within a Bayesian framework to fit the model and simulate HIV transmission in the high and low-risk population of Cotonou and to estimate HIV incidence and infections averted by SIDA1/2/3. Our model results suggest that prior to SIDA1/2/3 commercial sex had contributed directly or indirectly to 93% (84-98%) of all cumulative infections and that the observed decline in FSWs HIV prevalence was more consistent with the self-reported post-intervention increase in condom use by FSWs than a counterfactual assuming no change in condom use after 1993 (CF-1). Compared to the counterfactual (CF-1), the increase in condom use may have prevented 62% (52-71%) of new HIV infections among FSWs between 1993 and 2008 and 33% (20-46%) in the overall population. CONCLUSIONS: Our analysis provides plausible evidence that the post-intervention increase in condom use during commercial sex significantly reduced HIV prevalence and incidence among FSWs and general population. Sex worker interventions can be effective even in medium HIV prevalence epidemics and need to be sustained over the long-term.

Assessment of HIV-related risky behaviour: a comparative study of face-to-face interviews and polling booth surveys in the general population of Cotonou, Benin.

OBJECTIVES: During the 2008 HIV prevalence survey carried out in the general population of Cotonou, Benin, face-to-face interviews (FTFI) were used to assess risky behaviours for HIV and other sexually transmitted infections (STI). We compared sexual behaviours reported in FTFI with those reported in polling booth surveys (PBS) carried out in parallel in an independent random sample of the same population. METHODS: In PBS, respondents grouped by gender and marital status answered simple questions by putting tokens with question numbers in a green box (affirmative answers) or a red box (negative answers). Both boxes were placed inside a private booth. For each group and question, data were gathered together by type of answer. The structured and gender-specific FTFI guided by trained interviewers included all questions asked during PBS. Pearson χ2 or Fisher's exact test was used to compare FTFI and PBS according to affirmative answers. RESULTS: Overall, respondents reported more stigmatised behaviours in PBS than in FTFI: the proportions of married women and men who reported ever having had commercial sex were 17.4% and 41.6% in PBS versus 1.8% and 19.6% in FTFI, respectively. The corresponding proportions among unmarried women and men were 16.1% and 25.5% in PBS versus 3.9% and 13.0% in FTFI, respectively. The proportion of married women who reported having had extramarital sex since marriage was 23.6% in PBS versus 4.6% in FTFI. CONCLUSIONS: PBS are suitable to monitor reliable HIV/STI risk behaviours. Their use should be expanded in behavioural surveillance.

Decline in the prevalence of HIV and sexually transmitted infections among female sex workers in Benin over 15 years of targeted interventions.

BACKGROUND: An HIV-preventive intervention targeting the sex work milieu and involving fully integrated components of structural interventions, communication for behavioral change and care for sexually transmitted infections (STIs), was implemented in Benin by a Canadian project from 1992 to 2006. It first covered Cotonou before being extended to other main cities from 2000. At the project end, the Beninese authorities took over the intervention, but structural interventions were interrupted and other intervention components were implemented separately. We estimated time trends in HIV/STI prevalence among female sex workers (FSWs) from 1993 to 2008 and assessed the impact of the change in intervention model on trends. METHODS: Six integrated biological and behavioral surveys were carried out among FSWs. Time trend analysis controlled for potential sociodemographic confounders using log-binomial regression. RESULTS: In Cotonou, from 1993 to 2008, there was a significant decrease in HIV (53.3%-30.4%), gonorrhea (43.2%-6.4%), and chlamydia (9.4%-2.8%) prevalence (all adjusted P = 0.0001). The decrease in HIV and gonorrhea prevalence was also significant in the other cities between 2002 and 2008. In 2002, gonorrhea prevalence was lower in Cotonou than elsewhere (prevalence ratio = 0.53, 95% confidence interval: 0.32 to 0.88). From 2005 to 2008, there was an increase in gonorrhea prevalence (prevalence ratio = 1.76, 95% confidence interval: 1.17 to 2.65) in all cities combined. CONCLUSIONS: Our results suggest a significant impact of this targeted preventive intervention on HIV/STI prevalence among FSWs. The recent increase in gonorrhea prevalence could be related to the lack of integration of the intervention components.

Decline in HIV prevalence among young men in the general population of Cotonou, Benin, 1998-2008.

OBJECTIVE: To assess changes in the prevalence of HIV and other sexually transmitted infections, as well as in different proximal and distal factors related to HIV infection, in the general population of Cotonou between 1998 and 2008, while an intensive preventive intervention targeting the sex work milieu was ongoing. METHODS: A two-stage cluster sampling procedure was used to select the participants in each study. Subjects aged 15-49 who agreed to participate were interviewed and tested for HIV, syphilis, HSV-2, gonorrhoea and chlamydia. We used the Roa-Scott Chi-square test (proportions) and the Student's t test (means) for bivariate comparisons, and adjusted logistic regression models taking into account the cluster effect for multivariate analyses. RESULTS: HIV prevalence decreased significantly in men (3.4% in 1998 versus 2.0% in 2008, p = 0.048), especially in those aged 15-29 (3.0% to 0.5%, p = 0.002). Among men, the prevalence of gonorrhoea decreased significantly (1.1% to 0.3%, p = 0.046) while HSV-2 prevalence increased from 12.0% to 18.1% (p = 0.0003). The proportion of men who reported condom use at least once (29.3% to 61.0%, p<0.0001) and of those having attained a secondary educational level or more (17.1% to 61.3%, p<0.0001) also increased significantly. There was an overall decrease in the prevalence of syphilis (1.5% to 0.6%, p = 0.0003). CONCLUSION: This is the first population-based study reporting a significant decline in HIV prevalence among young men in an African setting where overall prevalence has never reached 5%. The decline occurred while preventive interventions targeting the sex work milieu were ongoing and the educational level was increasing.

Correlates of condom use among sex workers and their boyfriends in three West African countries.

The aim of this study was to identify correlates associated with condom use at last intercourse between sex workers (SW) and their boyfriends (BF). The sample was derived as a convenience sample recruited through existing HIV prevention organizations in Benin, Guinea and Senegal. The Theory of Planned Behavior served as the conceptual framework. A total of 406 individuals (220 SW and 186 BF) participated in the study. Socio-demographic, behavioral and psychological variables were collected through a face-to-face administered questionnaire. Condom use at last intercourse was significantly associated with intention and perceived control among SW as well as their BF. With respect to intention, perceived control, attitude and moral norm explained 82 and 74% of intention of SW and BF, respectively. These results suggest that promoting condom use among SW and BF should be based primarily on the development of personal ability to overcome obstacles to condom use.