A Structural Intervention for Most-At-Risk Populations in Mombasa, Kenya

Principal Investigator(s): 


Theo Sandfort, PhD

Peter Gichangi, MBCHB, MMED(O/G), PhD

Yves Lafort, MD

Sophie Vusha Chabeda, MSc

Funding Agency:

National Institute of Mental Health (NIMH)

Collaborating Institution: 

International Center for Reproductive Health, Mombasa, Kenya

International Center for Reproductive Health, Ghent University

Study Location:

Mombasa, Kenya


Female and male sex workers (FSW and MSW) are at heightened risk for acquiring and transmitting HIV infection because of biological, behavioral and structural risk factors. In Kenya’s Coast Province, a hotspot for sex work, sex workers (SW) and clients accounted for 18.2% of new HIV infections, and men who have sex with men (MSM) (including 9.2% of those in prison) for 20.5% – both higher than the national average. These data suggest that most current HIV prevention initiatives for these most-at-risk populations (MARP) are inadequate and ineffective. Given overlapping sexual networks among FSW and MSW and clients and that many MSM who engage in sex work have primary female sexual partners, MSW potentially play an important role in heterosexual HIV transmission dynamics.  
To date, few HIV prevention interventions have addressed comprehensively the intersecting social worlds of SW, clients, and settings in which sex is transacted. The majority of venue-based interventions for SW worldwide have been implemented in brothels, or other sex work-specific establishments. With few exceptions, especially in Africa, they have neither taken place in bars/clubs, nor targeted clients and MSW. In sub-Saharan Africa, bars/nightclubs, in which male and female sex work is ubiquitous, are ideal for launching a multi-level HIV prevention intervention that actively engages managers, bar staff, and actors involved in transactional sex as allies in HIV prevention, particularly since alcohol use can fuel HIV risk behaviors among SWs and clients. Therefore, we are piloting a multi-level intervention in nightclubs/bars in Mombasa, Kenya.

The specific aims of this three-phase, mixed-methods study are to:  
1.    Understand the socio-cultural context of risk behavior, beliefs/understandings of HIV and risk; barriers to and facilitators of risk-reduction; and responses to intervention messages among 25 male clients, 25 MSW, and 25 FSW via formative research to inform intervention content to be refined in Phase 2 (Phase 1).
2.    In collaboration with local key informants, design a multi-level risk-reduction intervention tailored to the local context and informed by theory and our prior work, that includes peer-delivered individual and group education, distribution of male and female condoms and lubricants, “street theater” presentations, on-site “moonlight” HIV testing and counseling (HTC) and STI care, and manager meetings in Mombasa bars and nightclubs (Phase 2). 
3.    Test the intervention package developed in Phase 2 for feasibility, acceptability, as well as participant level of exposure and intervention contamination at control sites via process measures.
4.    Test the feasibility of an intervention evaluation design (in Phase 3) to be used in a future study:
(a)    Assess recruitment and data collection procedures; 
(b)    Determine the usefulness of potential biomarkers of condom use; 
(c)    Assess retention of a longitudinal cohort of FSW, MSW, and clients;   
(d)    Develop power and sample size calculations to inform feasibility for a future venue-based combination prevention trial; 
(e)    Compare alternative ways of measuring condom use
Study findings will contribute to our understanding of the multi-level influences that facilitate HIV transmission in entertainment venues and advance HIV prevention science by building the evidence for what works for these MARP.


Publications /

  • Restar A, Tocco JU, Mantell JE, Lafort Y, Gichangi P, Masvawure TB, Chabeda SV, Sandfort TGM. (2017). Perspectives on HIV pre- and post- exposure prophylaxes (PrEP/PEP) among female and male sex workers in Mombasa, Kenya: Implications for integrating biomedical prevention into sexual health services. AIDS Education and Prevention. 29(2):141-153.
  • Mantell JE, Gichangi P, Tocco J, King’ola N, Sandfort T, Lafort Y.  Social and
    economic dynamics of male sex work in Mombasa, Kenya.  AIDS Impact, Amsterdam, The Netherlands, 28-31 July 2015.

  • Chabeda SV, Gichangi P, Masvawure TB, Mantell JE, Tocco JU, Restar A, Lafort Y, Sandfort TG. Perceptions of sexual and gender-based violence by female sex workers and male clients in Mombasa, Kenya. Abstract Number #THPED290. International AIDS Conference, Durban, South Africa, 19-23 July 2016.

  • Mantell JE, Masvawure TB, Tocco JU, Sandfort TG, Chabeda SV, Restar A, Gichangi P, Lafort Y. Not what we agreed”: Male sex workers' experiences of physical and sexual violence from their clients in Mombasa, Kenya. Abstract No. #THPEC152.   International AIDS Conference, Durban, South Africa, 19-23 July 2016.

  • Restar A, Lafort Y, Tocco JU, Gichangi P, Masvawure TB, Mantell JE, Chabeda SV, Sandfort TG. “Yes, I would like to use them, because sex is my work”: Awareness of and willingness to use pre- and post-exposure prophylaxes (PrEP and PEP) among female and male sex workers in Mombasa, Kenya.  Abstract No. #WEPED390A.  International AIDS Conference, Durban, South Africa, 19-23 July 2016.

  • Masvawure TB, Mantell JE, Tocco JU, Gichangi P, Restar A, Chabeda SV, Lafort Y, Sandfort TG. Who dunnit? Intentional and unintentional condom breakage in sexual interactions between female and male sex workers and their clients in Mombasa, Kenya. Abstract No.  #THPED357.  International AIDS Conference, Durban, South Africa, 19-23 July 2016.