Examining the Interplay Between Preexposure Prophylaxis (PrEP) and Gender-Related Stigmas as Barriers for PrEP Uptake Among Transgender Women in Tijuana, Mexico: A Mixed-Methods Study.

HIV prevalence among transgender women (TW) in Tijuana, Mexico is estimated at 22%. Pre-exposure prophylaxis (PrEP) reduces the risk of HIV acquisition by > 90%, though uptake in Tijuana has been low due to limited availability. The interplay between PrEP and gender stigmas may also serve as a barrier to PrEP uptake among TW in Tijuana. Experiences of gender- and PrEP- stigmas were assessed quantitatively (Quan) among 110 HIV-negative TW and qualitatively (Qual) among 17 TW through semi-structured interviews guide by the Health Stigma and Discrimination Framework. Qual findings were triangulated with Quant data to identify factors that may support gender affirmation and reduce PrEP stigma in an explanatory sequential Quan → Qual fashion. Most participants were < 40 years of age (80%), while approximately half had at least a high school education (48.2%) and were accessing gender-affirming hormone therapy (56.4%). Mean expectations of gender stigma were greatest for endorsing negative future expectations from others (M = 17.69; possible range 0-36). PrEP stigma was prominent among those who associated negative stereotypes with PrEP users, such as poor judgment (M = 45.91; possible range 14-70) and high personal risk attributes (M = 28.61; possible range 12-60). While PrEP knowledge was low among the qualitative sample, participants identified gender-, PrEP-, and intersectional- stigmas as potential barriers to PrEP uptake. Participants suggested that resilience strategies used to combat gender stigma could also mitigate PrEP stigma. Enhancing resilience skills at the intersection of gender and PrEP stigma may reduce these barriers, facilitating greater PrEP uptake as it becomes more available in Mexico.

Long-acting Injectable PrEP Interest and General PrEP Awareness among People who Inject Drugs in the San Diego-Tijuana Border Metroplex.

Long-acting injectable HIV pre-exposure prophylaxis (LAI-PrEP) could help overcome multilevel challenges to HIV prevention for people who inject drugs (PWID), including those in the binational San Diego-Tijuana metroplex. Yet, general PrEP awareness and interest in LAI-PrEP remain underexplored among PWID. From 2020 to 2021, 562 HIV-negative PWID in San Diego and Tijuana completed surveys assessing general PrEP awareness and interest in oral and LAI-PrEP. Modified Poisson regression examined factors associated with general PrEP awareness. Multinomial logistic regression assessed factors associated with interest in both oral and LAI-PrEP, oral PrEP only, LAI-PrEP only, or neither. General PrEP awareness was low (18%) and associated with experiencing unsheltered homelessness (adjusted prevalence ratio [APR] = 1.50, 95% confidence interval [CI]: 0.96-2.33), past 6-month fentanyl injection (APR = 1.53, 95% CI: 1.04-2.25), and transactional sex (APR = 1.71, 95% CI: 1.06-2.76). Interest in oral PrEP only was most common (44%), followed by LAI-PrEP only (25%) and neither (16%). Compared to the odds of being interested in LAI-PrEP only, the odds of being interested in oral PrEP only were lower among those who were stopped by police (AOR = 0.38, 95% CI: 0.22-0.65), reported past 6-month fentanyl injection (AOR = 0.33, 95% CI: 0.20-0.56), polydrug use (AOR = 0.48, 95% CI: 0.27-0.86), injecting multiple times daily (AOR = 0.26, 95% CI: 0.14-0.46), receptive syringe use (AOR = 0.30, 95% CI: 0.19-0.49), and higher perceived HIV risk (AOR = 0.24, 95% CI: 0.15-0.39). Interest in LAI-PrEP was more common among PWID reporting social and structural factors that could interfere with oral PrEP adherence, suggesting LAI-PrEP implementation could increase PrEP coverage among those most vulnerable to HIV.

Decentralized HIV testing: comparing peer and mail-based distribution strategies to improve the reach of HIV self-testing among people who use drugs in Florida.

INTRODUCTION: People who use drugs (PWUD) are at increased risk for HIV infection. HIV self-testing (HIVST) is a promising method for identifying new infections, but optimal distribution strategies remain understudied. METHODS: To characterize PWUD by HIVST distribution strategy (peers vs. mail), we examined data from July 2022 to June 2023 collected from a real-world HIVST program led by the non-profit, Florida Harm Reduction Collective. We used descriptive statistics and Poisson regressions with robust error variance to compare those who received HIVST through peers or via mail by socio-demographics, Ending the HIV Epidemic (EHE) county designation, and HIV testing experience. RESULTS: Among 728 participants, 78% received HIVST from peers, 47% identified as cisgender female, 48% as heterosexual, and 45% as non-White; 66% resided in an EHE county, and 55% had no HIV testing experience. Compared to those who received an HIV self-test from peers, those who received tests via mail were less likely to be cisgender male (vs. cisgender female; prevalence ratio [PR] = 0.59, 95% confidence interval [CI]: 0.43, 0.81), non-Hispanic Black (vs. non-Hispanic White; PR = 0.57, 95% CI: 0.36, 0.89) or from EHE counties (vs. non-EHE counties; PR = 0.33, 95% CI: 0.25, 0.44). Those who received tests via mail were also more likely to identify their sexual orientation as "Other/Undisclosed" (vs. straight/heterosexual; PR = 2.00, 95% CI: 1.51, 2.66). CONCLUSION: Our findings support the role of community-based HIVST distribution strategies in increasing HIV testing coverage among PWUD. Additional research could help inform the equitable reach of HIVST.

Willingness to use and distribute HIV self-testing kits among people who inject drugs in the San Diego-Tijuana border region.

BACKGROUND: HIV self-testing (HIVST) could increase HIV testing access among people who inject drugs (PWID), and secondary distribution (i.e., peer-delivery) of HIVST kits in PWID social networks could further expand coverage. We assessed willingness to use and distribute HIVST kits among PWID in the San Diego-Tijuana border region. METHODS: From 2020 to 2021, HIV-negative PWID in San Diego, USA, and Tijuana, Mexico, completed surveys and provided data on individual (N = 539) and social network (N = 366) characteristics. We used modified Poisson regression to examine the effects of individual and social network characteristics on willingness to use and distribute HIVST kits. RESULTS: Most participants were willing to use (81%) and distribute (81%) HIVST kits. At the individual level, prior HIV testing was positively associated with willingness to use (adjusted prevalence ratio [aPR] = 1.24, 95% confidence interval [CI] 1.10-1.40) and distribute (aPR = 1.27, 95% CI 1.12-1.43) HIVST kits, while perceiving oneself to be at higher HIV risk than others was negatively associated with willingness to use HIVST kits (aPR = 0.83, 95% CI 0.74-0.93). At the network level, willingness to distribute HIVST kits was positively associated with network size (aPR = 1.04 per member, 95% CI 1.01-1.08) and greater proportions of one's network encouraging them to use drugs (aPR = 1.29, 95% CI 1.16-1.44) and having a history of homelessness (aPR = 1.51, 95% CI 1.31-1.74) or detention/arrest (aPR = 1.57, 95% CI 1.36-1.82), and negatively associated with a greater proportion of one's network including "very close" persons (aPR = 0.80, 95% CI 0.69-0.94). CONCLUSIONS: We found high potential for HIVST kits and their secondary distribution to increase HIV testing among PWID who face the greatest barriers to facility-based testing.

Health, harm reduction, and social service providers' perspectives on the appropriateness and feasibility of peer distribution of HIV self-test kits among people who use drugs.

BACKGROUND: People who use drugs (PWUD) experience elevated HIV risk and numerous barriers to facility-based HIV testing. HIV self-testing (HIVST) could circumvent many of those barriers and is acceptable among PWUD, yet HIVST implementation for PWUD is limited. Service providers' perspectives on specific HIVST delivery strategies could help increase availability for PWUD. METHODS: From April-November 2021, we interviewed 16 health, harm reduction, and social service providers working with PWUD in San Diego, CA. Interviews and rapid thematic analysis explored perspectives on HIVST's utility and appropriateness, as well as the feasibility of and anticipated challenges with specific HIVST delivery strategies, including peer or secondary distribution. RESULTS: Participants viewed HIV as a significant threat to PWUD health and confirmed the presence of numerous barriers to local facility-based HIV testing. Participants viewed HIVST as a promising and potentially empowering solution. Based on community familiarity with secondary distribution of harm reduction supplies (i.e., naloxone) and information, participants viewed secondary distribution of HIVST kits as an appropriate and feasible strategy for increasing the reach of HIVST, but also described potential barriers (e.g., engaging socially disconnected individuals, ensuring linkages to services following HIVST) and provided suggestions for alternative HIVST kit delivery models (e.g., harm reduction vending machines). CONCLUSIONS: Service providers viewed secondary distribution of HIVST kits among PWUD as promising, appropriate, and feasible, yet specialized efforts may be needed to reach the most marginalized individuals and ensure consistent provision of educational information and referral supports that maximize the impact of this approach.

Correlates of impulsivity among female sex workers in Mexico.

Impulsivity is a trait characteristic that is associated with sexual risk behavior. We examined correlates of impulsivity among 602 female sex workers (FSWs) enrolled in a sexual risk reduction intervention in Mexico (2016-2020). Impulsivity was positively associated with condomless sex with clients. Higher levels of impulsivity were associated with greater use of alcohol and heavy drugs, use of illicit drugs with clients, sexual/physical abuse history, and clinical depression. Global public health policy that supports free substance abuse treatment in combination with psychotherapeutic treatments (e.g. regulation management skills) and behavioral-focused therapy may help to reduce HIV/STI incidence in this vulnerable population.

Dynamics and Dispersal of Local Human Immunodeficiency Virus Epidemics Within San Diego and Across the San Diego-Tijuana Border.

BACKGROUND: Evolutionary analyses of well-annotated human immunodeficiency virus (HIV) sequence data can provide insights into viral transmission patterns and associated factors. Here, we explored the transmission dynamics of the HIV-1 subtype B epidemic across the San Diego (US) and Tijuana (Mexico) border region to identify factors that could help guide public health policy. METHODS: HIV pol sequences were collected from people with HIV in San Diego County and Tijuana between 1996-2018. A multistep phylogenetic approach was used to characterize the dynamics of spread. The contributions of geospatial factors and HIV risk group to the local dynamics were evaluated. RESULTS: Phylogeographic analyses of the 2034 sequences revealed an important contribution of local transmission in sustaining the epidemic, as well as a complex viral migration network across the region. Geospatial viral dispersal between San Diego communities occurred predominantly among men who have sex with men, with central San Diego being the main source (34.9%) and recipient (39.5%) of migration events. HIV migration was more frequent from San Diego county towards Tijuana than vice versa. Migrations were best explained by the driving time between locations. CONCLUSIONS: The US-Mexico border may not be a major barrier to the spread of HIV, which may stimulate coordinated transnational intervention approaches. Whereas a focus on central San Diego has the potential to avert most spread, the substantial viral migration independent of central San Diego shows that county-wide efforts will be more effective. Combined, this work shows that epidemiological information gleaned from pathogen genomes can uncover mechanisms that underlie sustained spread and, in turn, can be a building block of public health decision-making.

A Randomized Controlled Trial of a Texting Intervention to Maintain Sexual Risk Reduction with Clients Among Female Sex Workers in Tijuana and Ciudad Juarez, Mexico.

Mobile phone technology may help sustain reductions in HIV/STI transmission risk behaviors among female sex workers (FSWs). We examined the efficacy of a text messaging intervention designed to maintain behavioral improvements in safer sex practices among 602 FSWs in Tijuana and Ciudad Juarez, Mexico. We hypothesized that FSWs who received brief risk reduction counseling and theory-based safer sex maintenance text messages over a 24-month period would have fewer incident HIV/STIs and report greater maintenance of safer sex practices compared to FSWs who received counseling and texts on maintaining general health. Theory-based texts did not change the odds of becoming infected with HIV/STIs in either study site. However, they did lead to significant, sustained protected sex in Tijuana. Theory-based text messaging interventions may help sustain reductions in sexual risk behavior among FSWs.Trial Registration Clinical Trials.gov. Identifier: NCT02447484.

Perceived barriers to pre-exposure prophylaxis use and the role of syndemic factors among female sex workers in the Mexico-United States border region: a latent class analysis.

Female sex workers (FSWs) experience syndemic factors (e.g., polydrug use, hazardous alcohol consumption, client-perpetrated violence, depression, and sexually transmitted infections) that often heighten vulnerability to HIV and limit healthcare utilization. We hypothesized that syndemic factors will limit FSWs' uptake of pre-exposure prophylaxis (PrEP). From 2016 to 2017, 295 HIV-negative FSWs were enrolled in a behavioral HIV prevention trial in Tijuana and Ciudad Juarez, Mexico, underwent STI testing, and completed surveys on syndemic factors and perceived barriers to PrEP use. Syndemic scores (0-5) were calculated by summing syndemic factors. Latent class analysis (LCA) was used to identify homogeneous classes with respect to perceived barriers to PrEP use. We identified four classes: (1) perceived healthcare access barriers (8.3%), (2) perceived financial barriers (18.7%), (3) high level of perceived barriers (19.9%), and (4) low level of perceived barriers (53.0%) to PrEP use. Those experiencing three (adjusted odds ratio [aOR] = 3.63, 95% confidence interval [CI] = 1.24-10.67) and four or five (aOR = 6.30, 95% CI = 1.70-23.35) syndemic factors had a higher odds of membership in the class characterized by a high level of perceived barriers than in the class characterized by a low level of perceived barriers. Addressing syndemic factors may maximize PrEP's impact among FSWs along Mexico's northern border.

Maternal role strain and depressive symptoms among female sex workers in Mexico: the moderating role of sex work venue.

Stressors that arise in parenting are likely to have an adverse impact on the psychological well-being of female sex workers (FSWs), particularly in low- to middle-income countries (LMIC). This study examined the association between maternal role strain and depressive symptoms among 426 FSW mothers with dependent-age children (aged < 18 years) in Tijuana and Cd. Juarez, Mexico (2016-2017). Four dimensions of maternal role strain (e.g., child emotional and behavioral problems) were examined in relation to maternal depressive symptoms. We also investigated whether the relationship between maternal role strain and depressive symptoms was modified by venue of sex work. Compared to indoor/establishment-based FSWs, street-based FSWs reported significantly more child-related financial strain. In multiple regression analysis, having more depressive symptoms was associated with identifying as a street-based FSW, greater use of drugs, lower emotional support, more child-related financial strain and more emotional and behavioral problems in children. A significant interaction was identified such that the association between maternal role strain and depressive symptoms was stronger for indoor/establishment-based compared to street-based FSWs. These findings suggest the need to address parenting strain and type of sex work venue in the development of counseling programs to improve the mental health of FSWs in LMIC.

Impact of time perspectives on texting intervention to reduce HIV/STI transmission among female sex workers in Tijuana and Ciudad Juarez, Mexico.

Text messages may sustain post-counseling gains in behavioral improvements and reduce HIV/STI incidence. However, their effectiveness may depend on the messages' time perspective and characteristics of the individual. We evaluated the impact of time perspective on a text messaging intervention designed to maintain improvements in safer sex practices among drug-using and non-drug-using female sex workers (FSWs) in Tijuana (n = 141) and Cd. Juarez (n = 129), Mexico. FSWs received the efficacious Mujer Segura intervention, and were randomized to receive safer sex maintenance text messages with either a short-term or future-oriented time perspective. The outcome was HIV/STI incidence rate over 6-month follow-up. In Tijuana, combined HIV/STI incidence density was lower among FSWs in the FUTURE group (31.67 per 100 py) compared to women in the SHORT-TERM group (62.40 per 100 py). Conversely, in Cd. Juarez, HIV/STI incidence density was lower (although non-significant) among FSWs in the SHORT-TERM group (19.80 per 100 py) compared to those in the FUTURE group (35.05 per 100 py). These findings suggest that future-oriented text messages may sustain post-counseling improvements in sexual risk behavior among FSWs, but findings may vary by FSWs' characteristics (e.g., drug use), and by region and context.

Uptake of a Partner Notification Model for HIV Among Men Who Have Sex With Men and Transgender Women in Tijuana, Mexico.

Undiagnosed HIV infection is common among men who have sex with men (MSM) and transgender women (TW) in Latin America. We examined uptake of a partner notification (PN) model among MSM and TW in Tijuana, Mexico. Forty-six HIV-positive MSM/TW enrolled as index patients, and reported 132 MSM/TW sexual partners for PN. Of notified partners (90/132), 39% declined eligibility screening or participation, 39% tested for HIV, and of those 28% were newly-diagnosed HIV-positive. Partners who were seen by the index patient more than once in the past 4 months and those who primarily had sex with the index patient in one of their homes were more likely to be notified via PN (76% vs. 50%; p = 0.01 and 86% vs. 64%, p = 0.02, respectively). Lower than expected PN uptake was associated with problems identifying index patients, obtaining reliable partner contact information, and engaging notified partners.

Factors in the HIV risk environment associated with bacterial vaginosis among HIV-negative female sex workers who inject drugs in the Mexico-United States border region.

BACKGROUND: Bacterial vaginosis (BV) is the most common cause of vaginitis among women worldwide and is associated with increased susceptibility to sexually transmitted infections (STIs), including HIV. We aimed to determine the impact of the HIV risk environment on BV among female sex workers who inject drugs (FSW-PWIDs) in Tijuana and Ciudad Juarez, Mexico. METHODS: We performed a cross-sectional analysis utilizing baseline data from a randomized controlled trial evaluating a behavioral HIV prevention intervention. Participants underwent testing for BV using the OSOM BVBlue® Rapid Test (Genzyme Diagnostics, San Diego, CA) and completed a survey eliciting information on the HIV risk environment, sexual risk behaviors, and substance use. We applied logistic regression to identify correlates of BV in the physical, social, economic, and political HIV risk environments stratified by study site (Ciudad Juarez vs. Tijuana). RESULTS: In total, 584 HIV-negative FSW-PWIDs (300 Ciudad Juarez; 284 Tijuana) were enrolled. The prevalence of BV was 39% (n = 228), which was higher in Ciudad Juarez (56.7%) compared to Tijuana (20.4%). In both cities, micro-level components of the physical HIV risk environment were associated with BV. In Ciudad Juarez, BV was associated with past experiences or threats of physical violence in response to proposed condom use (adjusted odds ratio [aOR] = 3.66, 95% confidence interval [CI]: 1.74-7.69, p = 0.001) and lifetime residence in Ciudad Juarez (aOR = 1.74, 95% CI: 1.05-2.87, p = 0.031). In Tijuana, BV was associated with the number of hours spent on the street daily in the past six months looking for, using, or dealing drugs, engaging in other income generating activities, or sleeping (aOR = 1.05, 95% CI: 1.001-1.097, p = 0.045). CONCLUSIONS: Our findings suggest that FSW-PWIDs' risk of BV may be shaped by the microphysical HIV risk environment. Addressing components of the physical risk environment, including interventions to reduce gender-based violence, may alleviate the burden of BV and subsequent susceptibility to HIV/STIs among FSW-PWIDs in the Mexico/US border region. TRIAL REGISTRATION: National Institute of Health (NIH) Clinical Trials Identifier NCT00840658 , and date of NIH trial registration February 7, 2009.

Vaginal washing and lubrication among female sex workers in the Mexico-US border region: implications for the development of vaginal PrEP for HIV prevention.

BACKGROUND: To assess the potential acceptability and inform the development of behaviorally-congruent vaginal douche- or gel-based HIV pre-exposure prophylaxis (PrEP) products, we examined vaginal washing and lubrication practices among female sex workers (FSWs) in Tijuana and Ciudad Juarez, two northern Mexico cities bordering the United States (US). METHODS: Two hundred and ninety-five HIV-negative FSWs (145 Tijuana; 150 Ciudad Juarez) enrolled in a behavioral HIV prevention intervention trial completed surveys assessing vaginal washing and lubrication practices, as well as motivators and barriers to performing each practice. Logistic regression was used to identify potential predictors of each practice in the past month. RESULTS: In the past month, vaginal washing was performed by 56 and 22% of FSWs in Tijuana and Ciudad Juarez (p <  0.0001), respectively, while vaginal lubrication was performed by 64 and 45% of FSWs in Tijuana and Ciudad Juarez (p = 0.001), respectively. Vaginal washing was positively associated with living in Tijuana (adjusted odds ratio [AOR] = 4.35, 95% confidence interval [CI]: 2.60-7.30), older age (AOR = 1.04 per year, 95% CI: 1.01-1.06), and vaginal lubrication (AOR = 2.99, 95% CI: 1.67-5.35), while it was negatively associated with being born in the same state as the study site (AOR = 0.50, 95% CI: 0.31-0.82), earning a monthly income ≥3500 pesos (AOR = 0.53, 95% CI: 0.28-1.00), and hazardous alcohol consumption (AOR = 0.56, 95% CI: 0.33-0.95). Vaginal lubrication was positively associated with living in Tijuana (AOR = 2.21, 95% CI: 1.37-3.54) and vaginal washing (AOR = 2.91, 95% CI: 1.64-5.18), while it was negatively associated with being born in the same state as the study site (AOR = 0.47, 95% CI: 0.29-0.75). CONCLUSIONS: The moderate and high prevalence of vaginal washing and lubrication, respectively, suggest behaviorally-congruent, multi-purpose, vaginal douche- and gel-based PrEP products that simultaneously address FSWs' needs and prevent HIV infection may be acceptable to many FSWs along the Mexico-US border. Future product development and implementation should also consider the link between vaginal washing and lubrication to ensure existing practices do not undermine vaginal PrEP product effectiveness. TRIAL REGISTRATION: ClincialTrials.gov ( NCT02447484 ).

Sexual Partner Concurrency Among Partners Reported by MSM with Recent HIV Infection.

We examined concurrency among sexual partners reported by men who have sex with men (MSM) with recent (acute or early) HIV infection in San Diego, California (2002-2015). Partners overlapping in time in the past 3 months were considered concurrent. Logistic generalized linear mixed models were used to identify factors associated with concurrency at the partner-level. 56% (388/699) of partners were concurrent to ≥1 other partner. The odds of concurrency were higher among partners >10 years younger than the participant (vs. within 10 years of age) [adjusted odds ratio (AOR) = 2.22, 95% confidence interval (CI) 1.09-4.52], longer term partners (AOR per month = 1.02, 95% CI 1.01-1.03), and partners met online (AOR = 1.56, 95% CI 0.98-2.48). Concurrency is common among partners of recently HIV-infected MSM. Tailored HIV prevention strategies for MSM with older partners, longer term partners, and partners met online may help minimize the potential impact of concurrency on HIV transmission.

Individual-Level, Partnership-Level, and Sexual Event-Level Predictors of Condom Use During Receptive Anal Intercourse Among HIV-Negative Men Who Have Sex with Men in Los Angeles.

We examined individual-level, partnership-level, and sexual event-level factors associated with condom use during receptive anal intercourse (RAI) among 163 low-income, racially/ethnically diverse, HIV-negative men who have sex with men (MSM) in Los Angeles (2007-2010). At baseline, 3-month, and 12-month visits, computer-assisted self-interviews collected information on ≤3 recent male partners and the last sexual event with those partners. Factors associated with condom use during RAI at the last sexual event were identified using logistic generalized linear mixed models. Condom use during RAI was negatively associated with reporting ≥ high school education (adjusted odds ratio [AOR] = 0.32, 95 % confidence interval [CI] 0.11-0.96) and methamphetamine use, specifically during RAI events with non-main partners (AOR = 0.20, 95 % CI 0.07-0.53) and those that included lubricant use (AOR = 0.20, 95 % CI 0.08-0.53). Condom use during RAI varies according to individual-level, partnership-level, and sexual event-level factors that should be considered in the development of risk reduction strategies for this population.

Incidence and Predictors of HIV and Sexually Transmitted Infections Among Female Sex Workers and Their Intimate Male Partners in Northern Mexico: A Longitudinal, Multilevel Study.

Preventing human immunodeficiency virus (HIV) infection and other sexually transmitted infections (STIs) requires an understanding of sexual relationship factors beyond the individual level. We estimated HIV/STI incidence and identified time-varying predictors of STI acquisition in a prospective cohort study of female sex workers and their intimate (noncommercial) male partners in northern Mexico. From 2010 to 2013, couples underwent behavioral and biological assessments biannually for 24 months. Among 413 initially HIV-uninfected participants, 8 seroconverted during follow-up. Incidence of HIV (1.12 cases/100 person-years (PY)), chlamydia (9.47 cases/100 PY), active syphilis (4.01 cases/100 PY), and gonorrhea (1.78 cases/100 PY) was higher among women than among men (HIV: P = 0.069; all STIs combined: P < 0.001). In multivariable conditional logistic regression with individual fixed effects and correlated error terms within couples, risk of STI acquisition was significantly higher among women who had recently used cocaine, crack, or methamphetamine (adjusted odds ratio (OR) = 2.13, 95% confidence interval (CI): 1.07, 4.28). STI risk was lower among women who reported physically assaulting their male partners (adjusted OR = 0.44, 95% CI: 0.22, 0.86) and among men whose female partners had regular sex-work clients (adjusted OR = 0.38, 95% CI: 0.14, 1.03). Improving vulnerable couples' sexual health will require addressing the contexts in which drug use, interpersonal conflict, and economic vulnerability converge.

STI/HIV test result disclosure between female sex workers and their primary, non-commercial male partners in two Mexico-US border cities: a prospective study.

OBJECTIVES: Disclosure of sexually transmitted infections (STI)/HIV diagnoses to sexual partners is not mandated by public health guidelines in Mexico. To assess the feasibility of couples-based STI/HIV testing with facilitated disclosure as a risk-reduction strategy within female sex workers' (FSW) primary partnerships, we examined STI/HIV test result disclosure patterns between FSWs and their primary, non-commercial male partners in two Mexico-US border cities. METHODS: From 2010 to 2013, 335 participants (181 FSWs and 154 primary male partners) were followed for 24 months. At semiannual visits, participants were tested for STIs/HIV and reported on their disclosure of test results from the previous visit. Multilevel logistic regression was used to identify individual-level and partnership-level predictors of cumulative (1) non-disclosure of ≥1 STI test result and (2) non-disclosure of ≥1 HIV test result within couples during follow-up. RESULTS: Eighty-seven percent of participants reported disclosing all STI/HIV test results to their primary partners. Non-disclosure of ≥1 STI test result was more common among participants who reported an STI diagnosis as part of the study (adjusted OR=3.05, 95% CI 1.13 to 8.25), while non-disclosure of ≥1 HIV test result was more common among participants in longer-duration partnerships (AOR=1.15 per year, 95% CI 1.03 to 1.28). Drug use before/during sex within partnerships was associated with non-disclosure of both STI (AOR=5.06, 95% CI 1.64 to 15.62) and HIV (AOR=4.51, 95% CI: 1.32 to 15.39) test results. CONCLUSIONS: STI/HIV test result disclosure was highly prevalent within FSWs' primary partnerships, suggesting couples-based STI/HIV testing with facilitated disclosure may be feasible for these and potentially other high-risk, socially marginalised couples.

Commercial lubricant use among HIV-negative men who have sex with men in Los Angeles: implications for the development of rectal microbicides for HIV prevention.

To inform the development and assess potential use of rectal microbicide gels for HIV prevention among men who have sex with men (MSM), we examined the dynamics and contexts of commercial lubricant use during receptive anal intercourse (RAI) within this population. From 2007 to 2010, 168 HIV-negative MSM living in Los Angeles who practice RAI completed computer-assisted self-interviews, which collected information on their last sexual event with ≤3 recent partners, at baseline, three months, and one-year study visits. Logistic generalized linear mixed models were used to identify individual- and sexual event-level characteristics associated with commercial lubricant use during RAI at the last sexual event within 421 partnerships reported by participants over the course of follow-up. During RAI at their last sexual event, 57% of partnerships used a condom and 69% used commercial lubricant. Among partnerships that used commercial lubricant, 56% reported lubricant application by both members of the partnership, 66% first applied lubricant during sex, but before penetration, and 98% applied lubricant at multiple locations. The relationship between substance use and commercial lubricant use varied by condom use (interaction p-value = 0.01). Substance use was positively associated with commercial lubricant use within partnerships that did not use condoms during RAI at their last sexual event (AOR = 4.47, 95% [corrected] [CI]: 1.63-12.28), but no association was observed within partnerships that did use condoms (AOR = 0.66, 95% CI: 0.23-1.85). Commercial lubricant use during RAI was also positively associated with reporting more sexual partners (AOR = 1.18, 95% CI: 1.05-1.31), while older age (units = 5 years; AOR = 0.75, 95% CI: 0.61-0.94), homelessness (past year; AOR = 0.32, 95% CI: 0.13-0.76), and having sex with an older (>10 years) partner (AOR = 0.37, 95% CI: 0.14-0.95) were negatively associated with commercial lubricant use. These factors should be considered in the development of rectal microbicide gels to enhance their acceptability and use among MSM.

Determinants of HIV Pre-Exposure Prophylaxis (PrEP) Retention among Transgender Women: A Sequential, Explanatory Mixed Methods Study.

Transgender women (TW) face inequities in HIV and unique barriers to PrEP, an effective biomedical intervention to prevent HIV acquisition. To improve PrEP retention among TW, we examined factors related to retention using a two-phase, sequential explanatory mixed methods approach. In Phase I, we used data from a trial of 170 TW who were provided oral PrEP to examine predictors of 24-week retention. In Phase II, we conducted 15 in-depth interviews with PrEP-experienced TW and used thematic analysis to explain Phase I findings. In Phase I, more participants who were not retained at 24 weeks reported sex work engagement (18% versus 7%) and substantial/severe drug use (18% versus 8%). In Phase II, participants reported drug use as a barrier to PrEP, often in the context of sex work, and we identified two subcategories of sex work. TW engaged in "non-survival sex work" had little difficulty staying on PrEP, while those engaged in "survival sex work" struggled to stay on PrEP. In Phase I, fewer participants not retained at 24 weeks reported gender-affirming hormone therapy (GAHT) use (56% versus 71%). In Phase II, participants prioritized medical gender affirmation services over PrEP but also described the bidirectional benefits of accessing GAHT and PrEP. TW who engaged in "survival sex work" experience barriers to PrEP retention (e.g., unstable housing, drug use) and may require additional support to stay in PrEP care.