Relationships between drug and alcohol use and unprotected sex have been well documented among female sex workers (FSWs) since early in the HIV epidemic
]. In Holland
], FSWs who reported engaging in sex work while ‘high’ were more likely to report unsafe sex. In the UK
], FSWs’ drug use was associated with having unprotected sex in exchange for more money. Unfavorable working conditions including low earnings, limited access to condoms and violence from clients or intimate partners can lead some FSWs to acquiesce to demands for unsafe sex
], especially if they are suffering from withdrawal symptoms or rely on a partner for drugs
]. Some FSWs exchange sex primarily for drugs
], and/or use drugs with clients, which may increase their risk of sharing injection equipment.
Since female sex workers who inject drugs (FSW-IDUs) are at high risk of becoming infected with HIV through unprotected sexual intercourse and sharing injection equipment with intimate partners, clients and peers, this subgroup meets criteria for a ‘bridge’ population that is associated with generalized HIV epidemics
]. Overlap between FSW and IDU populations is especially high in parts of Southeast and Central Asia
], and Argentina
] and is a growing concern in some Latin American countries, such as Mexico
Overlap between FSW and IDU populations in Mexico-U.S. border cities is due at least in part to a number of environmental influences. Sex work is quasi-legal in Mexico, and some Mexican cities (e.g., Tijuana, Baja California), maintain zona rojas (red zones) where sex work is tolerated among women aged 18 and older, provided that they subject to quarterly HIV/STI testing and are issued a work permit. Other cities such as Ciudad (Cd.) Juarez, Chihuahua tolerate sex work but do not regulate it. Cd. Juarez began gentrifying their zona roja district in 2008, leading FSWs to become dispersed. Both cities have experienced high levels of community-based violence associated with warring drug cartels, but this situation has been particularly severe in Cd. Juarez.
The proximity of Tijuana and Ciudad Juarez to the U.S. cities of San Diego, CA and El Paso, TX draws clients and sex tourists from the U.S. and internationally. In an earlier study, two thirds of FSWs in these cities reported having clients from the U.S., and those that did were more likely to engage in more HIV risk behaviors. Although no robust estimates of the number of FSWs exist for either city, there were an estimated 9,000 FSWs in Tijuana
] and 4000 FSWs in Ciudad Juarez in 2005
Mexico is one of the most important sources of heroin and methamphetamine entering the U.S.
] and it is estimated that 70% of all cocaine entering the U.S. passes through Mexico en route from South America. As a consequence, illicit drug use has increased in Tijuana and Cd. Juarez over the past decade as local consumption markets emerged along drug trafficking routes
]. In Mexico overall, men were 13 times more likely than women to have ever used an illicit drug, but in Tijuana the ratio was 6:1, indicating a high proportion of female drug users. Although no official estimates of the number of IDUs exist in Mexico, there were an estimated 10,000 IDUs in Tijuana in 2005
] and about 6,500 ‘heavy heroin users’ in Cd. Juarez
] in 2001.
Overlapping sex work and drug use along Mexico’s northern border has influenced local HIV epidemics. By the end of 2005, the estimated number of HIV-infected persons in Mexico was 182,000
] with HIV prevalence ~0.6% among adults aged 15–49. However, HIV prevalence was nearly double in Baja California, which ranked 2nd
in HIV prevalence among Mexico’s 32 states
].Although Chihuahua ranked 14th
in AIDS incidence across Mexico, a high proportion of cases were attributed to injection drug use
]. These national and state-level HIV/AIDS surveillance statistics mask a burgeoning HIV epidemic in Tijuana and Cd. Juarez, where HIV prevalence among FSWs rose from 2% in 2003 to 8%, and 12% among FSW-IDUs by 2006
]. Almost half of FSW-IDUs in these two cities had at least one sexually transmitted infection (STI), such as HIV, active syphilis, gonorrhea or Chlamydia
]. In Tijuana, HIV prevalence among female IDUs was 10% in 2006
]. Many FSWs in Tijuana and Cd. Juarez report using stimulants like methamphetamine or cocaine to help them cope or stay awake
], which is of concern since injection and non-injection use of these stimulants was independently associated with HIV infection among FSWs in both
In response to rising HIV prevalence among FSWs in Tijuana and Cd. Juarez, members of our research team conducted a two-arm randomized trial to determine whether a theoretically-based intervention using motivational interviewing was successful in increasing condom use among FSWs in these cities. Conducted from 2004–2006, the study found a 40% reduction in combined HIV/STI incidence associated with this intervention, which was called Mujer Segura
]. The intervention group also reported higher proportions of protected sex acts compared to the control arm. However, compared to FSWs who had never injected drugs, FSW-IDUs improved less and rates of needle sharing did not change. This was not surprising since the Mujer Segura
intervention did not focus on reducing drug-related risks, nor did it provide skills to negotiate condom use within the context of drug use.
The high overlap between FSW and IDU populations in countries that bear a high or growing burden of HIV infection suggests that interventions that focus only on safer sex or safer injection will be of limited effectiveness. Yet we could identify no interventions that simultaneously address both sexual and injection drug-related risks for FSW-IDUs. Similarly, we could find no published intervention that taught safer sex negotiation skills within the context of ongoing drug use by FSWs, their regular partners or clients.
The protocol herein describes a four-arm factorial randomized control trial called Mujer Mas Segura (Safer Women) to simultaneously test the efficacy of two behavioral interventions-- offered in interactive and didactic formats -- aimed at a) increasing condom use in the context of ongoing drug use; and b) decreasing syringe and paraphernalia sharing among FSW-IDUs in Tijuana and Cd. Juarez. We hypothesized that the joint effect of the interactive format of these interventions will generate greater risk reductions compared to the didactic formats of these interventions. Furthermore, we aimed to examine the extent to which theoretically-based components of these interventions (i.e., knowledge, self-efficacy, outcome expectancies, attitudes, and intentions) represent underlying mechanisms of change in primary outcomes (i.e., sexual and injection-related risk reductions).