HIV/STI Risks among FSWs and Their Non-Commercial Partners (Proyecto Parejas)
Funded by NIDA grant R01 DA027772; PI: Steffanie Strathdee
The overall goal of this project is to study the context and epidemiology of HIV, STIs and associated risk behaviors among high risk female sex workers (FSWs) and their non-commercial male partners, and the feasibility of couple-based interventions. Over the last 5 years, our binational research team has conducted studies of FSWs, their clients and injection drug users in several Mexico-US border cities, including Tijuana and Ciudad (Cd.) Juarez, adjacent from San Diego, CA and El Paso, TX, respectively. Over a few short years in these two cities, we have documented HIV prevalence rising from <1% to 6% among FSWs overall, and 14% among FSWs who inject drugs. Strikingly, HIV incidence among FSWs is 2.0 per 100 person-years (py), which is consistent with an emerging epidemic. Continued high STI incidence is contributing to this epidemic.
Although the HIV epidemic in these cities thus far remains concentrated, high rates of cross-border mobility and internal migration indicate potential for HIV and STIs to readily spread both north and south. The logical next step in curtailing the growing HIV epidemic on the Mexico-U.S. border is to investigate potential ‘bridge’ populations, such as FSWs’ male partners. We recently showed that a brief behavioral intervention designed to increase FSWs’ condom use with male clients reduced STI incidence among FSWs by 40%. Unfortunately, this intervention had no impact on FSWs’ condom use with their non-commercial partners, with whom they were twice as likely to have unprotected sex compared with clients. Among FSWs who reported consistent condom use with clients, STI incidence at follow-up was 20 per 100 py, yet STI prevalence among clients was <5%. On the other hand, half of FSWs with partners reported that they knew their main partners had concurrent sexual partners, and that one third of their partners injected drugs. These data suggest that FSWs’ non-commercial partners may be significant drivers of HIV/STI acquisition, which is supported by literature in other countries. The impact of this is not trivial; when 50% of partnerships in a population are concurrent, the size of the HIV epidemic after 5 years is 10 times larger as under sequential monogamy. Although dozens of studies have been conducted on FSWs in diverse settings, almost none have characterized FSWs’ non-commercial partners, who represent a crucial missing link in HIV/STI prevention. Efforts are needed to determine the extent to which FSWs’ and their main partners are amenable to interventions, either as individuals or as a couple. The proposed study of FSW-partner pairs (dyads) builds on our existing research infrastructure in Tijuana and Cd. Juarez to meet the following aims:
- To examine the a) social context and b) patterns of high risk sexual and substance using behaviors among high risk FSWs and their main non-commercial male partners, both within and outside of the partnerships, using a mixed-methods approach.
- To determine prevalence of HIV and specific STIs (i.e., syphilis, gonorrhea, Chlamydia, HSV-2) and associated correlates at the individual and partner level among pairs of high risk FSWs and their main non-commercial male partners.
- To prospectively identify predictors of STI incidence and their attributable risks at the individual and partner level among FSWs and their main non-commercial male partners.
- To determine the feasibility of conducting a behavioral intervention trial among high risk FSWs and their main non-commercial male partner at the a) partner level and b) individual level, using mixed methods.
To meet these aims, we will recruit 100 high risk FSWs and their 100 non-commercial main male partners in Tijuana and Cd. Juarez (N=200 dyads per city, 400 subjects total), who will undergo interviews and HIV/STI testing at baseline and follow-up for 24 months to address both clinical and behavioral outcomes (Aims 2 and 3). A subset (25 couples per city) will undergo in-depth interviews at baseline and once during follow-up to refine the quantitative survey, and inform a mixed methods analysis to address Aims 1 and 4. Using qualitative and quantitative methods, we will assess each partner’s interest in participating in a subsequent intervention, attrition and partnership dissolution, and potential barriers to interventions such as intimate partner violence (Aim 4). Our aims are consistent with the Office of AIDS Research Trans-NIH Prevention Strategy for 2010, which highlights the need “to study HIV-related risk and protective behaviors associated with HIV transmission in specific social and cultural contexts, such as the sexual dyad” and studies of HIV risk “related to cultural norms that affect disempowerment of women”. To our knowledge, the proposed study is the first prospective evaluation of FSWs and their non-commercial partners. Our binational research team is uniquely positioned to conduct this study, which will inform the response to the growing HIV crisis on the Mexico-U.S. border and efforts to curtail HIV transmission among FSWs and their partners in other resource-constrained settings.