Estimating the impact of a police education program on hepatitis C virus transmission and disease burden among people who inject drugs in Tijuana, Mexico: A dynamic modeling analysis

BACKGROUND AND AIMS

Criminalization of drug use and punitive policing are key structural drivers of hepatitis C virus (HCV) risk among people who inject drugs (PWID). A police education program (Proyecto Escudo) delivering training on occupational safety together with drug law content was implemented between 2015 and 2016 in Tijuana, Mexico, to underpin drug law reform implementation. We used data from a longitudinal cohort of PWID in Tijuana to inform epidemic modeling and assess the long-term impact of Escudo on HCV transmission and burden among PWID in Tijuana.

METHODS

We developed a dynamic, compartmental model of HCV transmission and incarceration among PWID and tracked liver disease progression among current and former PWID. The model was calibrated to data from Tijuana, Mexico, with 90% HCV seroprevalence. We used segmented regression analysis to estimate impact of Escudo on recent incarceration among an observational cohort of PWID. By simulating the observed incarceration trends, we estimated the potential impact of the implemented (2-year reduction in incarceration) and an extended (10-year reduction in incarceration) police education program over a 50-year follow-up (2016-2066) on HCV outcomes (incidence, cirrhosis, HCV-related deaths and disability adjusted life-years averted) compared with no intervention.

RESULTS

Over the 2-year follow-up, Proyecto Escudo reduced HCV incidence among PWID from 21.5 per 100 person years (/100py) (95% uncertainty interval [UI] = 15.3-29.7/100py) in 2016 to 21.1/100py (UI = 15.0-29.1/100py) in 2018. If continued for 10 years, Escudo could reduce HCV incidence to 20.0/100py (14.0-27.8/100py) by 2026 and avert 186 (32-389) new infections, 76 (UI = 12-160) cases of cirrhosis and 32 (5-73) deaths per 10 000 PWID compared with no intervention over a 50-year time horizon.

CONCLUSIONS

In Tijuana, Mexico, implementation of a police education program delivering training on occupational safety and drug law content appears to have reduced hepatitis C virus incidence among people who inject drugs.

Mexicans vs Central Americans: Violented Migrants Crossing Mexico

INTRODUCTION

The World Health Organization considers that migrants who pass through the Mexico-US walkway suffer high levels of violence, compared to other regions of the world, mainly women. This study aims to identify the factors associated with the types of violence suffered by migrants in transit through Mexico to the USA.

DESIGN

A cross-sectional, exploratory, retrospective, and observational study was conducted. A questionnaire of 46 variables was applied, divided into four sections: sociodemographic background, leaving the home, transit, and stay at the border. Questions about different types of direct violence were included. The survey was applied to 612 Mexican and Central American migrants who were in the Chaparral customs office and in five shelters in Tijuana City, on the U.S.-Mexico border. The results were analyzed using descriptive techniques and multivariate analysis of main and inferential components, using the statistical program R.

RESULTS

The higher vulnerability of Central American migrants compared to Mexicans was documented, specially of women that proportionally were the most negatively affected victims including all types of violence, making it evident that one of each four was violented sexually and among them, only 50% asked for medical assistance. The multivariate analysis determined that the duration of the trip, and the type of transport can generate greater violence.

CONCLUSIONS

The results highlight the greater vulnerability of Central American migrants in their transit through Mexico, mainly women and, likewise, the lack of effective public policies that guarantee the protection of the health, safety, and human rights of migrants.

Bacterial and Chemical Evidence of Coastal Water Pollution from the Tijuana River in Sea Spray Aerosol

Roughly half of the human population lives near the coast, and coastal water pollution (CWP) is widespread. Coastal waters along Tijuana, Mexico, and Imperial Beach (IB), USA, are frequently polluted by millions of gallons of untreated sewage and stormwater runoff. Entering coastal waters causes over 100 million global annual illnesses, but CWP has the potential to reach many more people on land via transfer in sea spray aerosol (SSA). Using 16S rRNA gene amplicon sequencing, we found sewage-associated bacteria in the polluted Tijuana River flowing into coastal waters and returning to land in marine aerosol. Tentative chemical identification from non-targeted tandem mass spectrometry identified anthropogenic compounds as chemical indicators of aerosolized CWP, but they were ubiquitous and present at highest concentrations in continental aerosol. Bacteria were better tracers of airborne CWP, and 40 tracer bacteria comprised up to 76% of the bacteria community in IB air. These findings confirm that CWP transfers in SSA and exposes many people along the coast. Climate change may exacerbate CWP with more extreme storms, and our findings call for minimizing CWP and investigating the health effects of airborne exposure.

Correlates of recent overdose among people who inject drugs in the San Diego/Tijuana border region

BACKGROUND

Along the Mexico-US border, illicitly manufactured fentanyls (fentanyl) have been detected in other illicit drugs, including street opioid formulations known as 'china white.' We studied correlates of recent overdose among people who inject drugs (PWID), focusing on the risk of knowlingly or unknowingly using fentanyl in china white.

METHODS

From October 2020 - September, 2021 we surveyed participants in San Diego, California and Tijuana, Mexico and employed Poisson regression to identify correlates of recent overdose.

RESULTS

Of 612 PWID, most were male (74.0 %), Latinx (71.9 %), US residents (67.0 %). Mean age was 43 years. In the last six months, 15.8 % experienced overdose, 31.0 % knowingly used fentanyl and 11.1 % used china white, of whom 77.9 % did not think it contained fentanyl. After controlling for sex and race, factors independently associated with risk of overdose included knowingly using fentanyl, using china white and not believing it contained fentanyl, recent drug rehabilitation, being stopped/arrested by police, and homelessness. Further, PWID who believed china white contained fentanyl were less likely to use it.

CONCLUSIONS

Both intentional fentanyl use and unintentional exposure to fentanyl via china white were associated with overdose risk; however, PWID who believed china white contained fentanyl were less likely to use it. These data suggest that advanced drug checking systems should be implemented to empower PWID to avoid dangerous street formulations or to plan their drug use knowing its contents. Other overdose risk factors such as decreased tolerance following drug treatment, police interactions, and homelessness also require urgent intervention.

Gender and the first-time provision of injection initiation assistance among people who inject drugs across two distinct North American contexts: Tijuana, Mexico and Vancouver, Canada

INTRODUCTION

Injection drug use initiation is commonly facilitated by other people who inject drugs (PWID). We investigated how the gender of PWID influences their risk of providing initiation assistance to others across two distinct geo-cultural settings.

METHODS

Data were drawn from two prospective cohorts in Tijuana, Mexico and Vancouver, Canada which conducted semi-annual interviews within the PReventing Injecting by Modifying Existing Responses (PRIMER) study. Participants consisted of PWID who had reported never providing injection initiation assistance at baseline. We then conducted site-specific discrete-time survival analyses assessing the relationship between gender and other relevant covariates (e.g. age and past 6-month sex work) on the risk of the first reported instance of providing initiation assistance.

RESULTS

Of 1988 PWID (Tijuana: n = 596; Vancouver: n = 1392), 256 (43%) and 511 (36.7%) participants were women, and 42 (1.7%) and 78 (1.6%) reported recent injection initiation assistance across a median of three and two follow-up visits, respectively. Women had a lower risk of providing injection initiation assistance for the first time in Tijuana (adjusted hazard ratio = 0.52, 95% confidence interval 0.27-0.99), but not in Vancouver. Gendered pathways, like sex work, were associated with providing initiation assistance for the first time in Vancouver (adjusted hazard ratio = 1.97, 95% confidence interval 1.08-3.61).

DISCUSSION AND CONCLUSIONS

Women in Tijuana, but not Vancouver, were less likely to provide first-time initiation assistance among PWID. These results can inform gender- and site-specific prevention efforts aimed at reducing transitions into drug injecting across geographic contexts.

Modeling Untreated Wastewater Evolution and Swimmer Illness for Four Wastewater Infrastructure Scenarios in the San Diego-Tijuana (US/MX) Border Region

The popular beaches of the San Diego-Tijuana (US/MX) border region are often impacted by untreated wastewater sourced from Mexico-via the Tijuana River Estuary (TJRE) and San Antonio de los Buenos outfall at the Pt. Bandera (SAB/PTB) shoreline, leading to impacted beaches and human illness. The US-Mexico-Canada trade agreement will fund border infrastructure projects reducing untreated wastewater discharges. However, estimating project benefits such as reduced human illness and beach impacts is challenging. We develop a coupled hydrodynamic, norovirus (NoV) pathogen, and swimmer illness risk model with the wastewater sources for the year 2017. The model is used to evaluate the reduction in human illness and beach impacts under baseline conditions and three infrastructure diversion scenarios which (Scenario A) reduce SAB/PTB discharges and moderately reduce TJRE inflows or (Scenarios B, C) strongly reduce TJRE in inflows only. The model estimates shoreline untreated wastewater and NoV concentrations, and the number of NoV ill swimmers at Imperial Beach CA. In the Baseline, the percentage of swimmers becoming ill is 3.8% over 2017, increasing to 4.5% during the tourist season (Memorial to Labor Day) due to south-swell driven SAB/PTB plumes. Overall, Scenario A provides the largest reduction in ill swimmers and beach impacts for the tourist season and full year. The 2017 tourist season TJRE inflows were not representative of those in 2020, yet, Scenario A likely still provides the greatest benefit in other years. This methodology can be applied to other coastal regions with wastewater inputs.

Impact of cumulative incarceration and the post-release period on syringe-sharing among people who inject drugs in Tijuana, Mexico: a longitudinal analysis

BACKGROUND AND AIMS

Syringe-sharing among people who inject drugs, which can occur during incarceration and post-release, has been linked with increased risk of blood-borne infections. We aimed to investigate the cumulative effect of repeated incarceration and the post-release period on receptive syringe-sharing.

DESIGN

Ongoing community-based cohort, recruited through targeted sampling between 2011 and 2012 with 6-month follow-ups.

SETTING

Tijuana, Mexico.

PARTICIPANTS

Sample of 185 participants (median age 35 years; 67% female) with no history of incarceration at study entry, followed to 2017.

MEASUREMENTS

Cumulative incarceration and post-release period were constructed from incarceration events reported in the past 6 months for each study visit. Receptive syringe-sharing in the past 6 months was assessed as a binary variable. We used logistic regression with generalized estimating equations to examine the association between cumulative incarceration events and the post-release period with receptive syringe-sharing over time. Missing data were handled through multiple imputation.

FINDINGS

At baseline, 65% of participants engaged in receptive syringe-sharing in the prior 6 months. At follow-up, 150 (81%) participants experienced a total of 358 incarceration events [median = 2, interquartile range (IQR) = 1-3]. The risk of receptive syringe-sharing increased with the number of repeated incarcerations. Compared with never incarcerated, those with one incarceration had 1.28 [95% confidence interval (CI) = 0.97-1.68] higher adjusted odds of syringe-sharing; two to three incarcerations, 1.42 (95% CI = 1.02-1.99) and more than three incarcerations, 2.10 (95% CI = 1.15-3.85). Participants released within the past 6 months had 1.53 (95% CI = 1.14-2.05) higher odds of sharing syringes compared with those never incarcerated. This post-release risk continued up to 1.5 years post-incarceration (adjusted odds ratio = 1.41, 95% CI = 1.04-1.91), but then waned.

CONCLUSIONS

A longitudinal community cohort study among people who inject drugs suggested that the effects of incarceration on increased injecting risk, measured through syringe-sharing, are cumulative and persist during the post-release period.

Examining the gender composition of drug injecting initiation events: A mixed methods investigation of three North American contexts

BACKGROUND

Gender influences the health and social risks faced by individuals initiating drug injecting. Using mixed methods across three settings in North America, we investigated the gender composition of injection initiation events and the gendered risk environments in which they occurred.

METHODS

The PReventing Injecting by Modifying Existing Responses (PRIMER) study pooled data from three prospective community-recruited cohorts of people who inject drugs (PWID) in San Diego, USA, Vancouver, Canada, and Tijuana, Mexico. A qualitative subsample provided narrative data on their experiences of, and the contexts for, injection initiation events. Guided by Rhodes' risk environment framework, we examined the gender composition of initiation events stratified by city, and analyzed qualitative data using abductive thematic analyses.

RESULTS

Among 2,622 PWID (Tijuana: n = 531; San Diego: n = 352; Vancouver: n = 1,739), 112 (4.3%) reported providing initiation assistance to injection-naïve individuals in the previous six months. The proportion of gender concordant (e.g., male-male) initiation pairs varied, (χ2 = 10.32, p <0.001) with greater than expected concordance among pairs in Tijuana compared with those in Vancouver or San Diego. Sixty-one interviews provided context for the discrepancy across sites by highlighting the gendered injection initiation risk environments of prison/jail detention in Tijuana, intimate partnerships in San Diego, and overdose risk in Vancouver.

CONCLUSIONS

These results highlight how gender influences injection initiation events within spatial, social, and economic risk environments, and how this influence varies across settings. These findings can inform interventions to reduce the risk of injection initiation and related harms.

Prevalence and correlates of cervical abnormalities among female sex workers in Tijuana, Mexico

Objectives:

In Tijuana, Mexico, sex work is regulated by the municipal health department and includes regular testing for HIV and other sexually transmitted infections (STIs) for registered female sex workers (FSWs). However, Pap testing is missing from current sexual health assessments. We aimed to answer the following research questions: 1.) What is the prevalence of cervical abnormalities among a sample of FSWs in Tijuana, Mexico? 2.) What are the correlates of cervical abnormalities among a sample of FSWs in Tijuana, Mexico?

Study design:

From 2013-2014, a cohort of 300 FSWs in Tijuana, Mexico were recruited using modified time-location sampling. Participants were given Pap, HIV, and STI tests.

Results:

The prevalence of an abnormal Pap was 11.7% (35/300). FSWs ever registered with municipal health services were less likely to have an abnormal Pap result (4.8% vs 14.4%, p=0.03), were more likely to report a previous Pap test (88.1% vs 70.4%, p=.001), and were more likely to report a sexual health checkup in the last year (60.7% vs 37.0%, p<0.001) than those who had never been registered.

Conclusions:

FSWs remain at risk for cervical abnormalities, including those registered with the municipality.

We conducted Pap testing for female sex workers in Tijuana, Mexico and found that over 11% had abnormal Pap test results.

Gender differences in the provision of injection initiation assistance: a comparison of three North American settings

AIM

Individuals experience differential risks in their initiation into drug injecting based on their gender. Data suggest women are more likely to be injected after their initiator and to share injection equipment. Little is known, however, regarding how gender influences the risk that people who inject drugs (PWID) may assist others into injection initiation. We therefore sought to investigate the role of "initiator" gender in the provision of injection initiation assistance across multiple settings.

METHODS

We employed data from PReventing Injecting by Modifying Existing Responses (PRIMER), a multi-cohort study investigating factors influencing injection initiation assistance provision. Data were drawn from three cohort studies of PWID in San Diego, USA (STAHR II); Tijuana, Mexico (El Cuete IV); and Vancouver, Canada (VDUS). Site-specific logistic regression models were fit, with lifetime provision of injection initiation assistance as the outcome and gender as the independent variable.

RESULTS

Overall, 3.2% (24/746) of the women and 4.6% (63/1367) of the men reported providing injection initiation assistance. In Tijuana, men were more than twice as likely to have provided injection initiation assistance after controlling for potential confounders (adjusted odds ratio = 2.17, 95% confidence interval: 1.22-3.84). Gender was not significantly associated with providing injection initiation assistance in other sites.

CONCLUSION

We identified that being male in Tijuana, specifically, was associated with providing injection initiation assistance, which could inform targeted outreach aimed at reducing the influence of PWID populations on non-injectors in this site. This will likely require that existing interventions address gender- and site-specific factors for effectiveness.

Increased non-fatal overdose risk associated with involuntary drug treatment in a longitudinal study with people who inject drugs

AIM

To assess the effect of involuntary drug treatment (IDT) on non-fatal overdose among people who inject drugs (PWID).

DESIGN

Longitudinal study.

SETTING

Tijuana, Mexico.

PARTICIPANTS

Baseline sample of 671 PWID included 258 (38.4%) women and 413 (61.6%) men.

MEASUREMENTS

Primary independent variables were reported recent (i.e. past 6 months) non-fatal overdose event (dependent variable) and IDT. Substance use the day of the non-fatal overdose was also examined.

FINDINGS

From 2011 to 2017, 213 participants (31.7%) reported a recent non-fatal overdose and 103 (15.4%) reported recent IDT. Heroin, in combination with methamphetamine and tranquilizers, were the drugs most reported at the day of the event. IDT significantly increased the odds of reporting a non-fatal overdose event [adjusted odds ratio (aOR) = 1.76; 95% confidence interval (CI) = 1.04-2.96]. Odds of non-fatal overdose also increased independently for each additional injection per day (aOR = 1.05; 95% CI = 1.02-1.08), recent tranquilizer use (aOR = 1.92; 95% CI = 1.41-2.61) and using hit doctors (aOR = 1.68; 95% CI = 1.29-2.18) and decreased with age (aOR = 0.97 per year, 95% CI = 0.95-0.99).

CONCLUSIONS

Recent involuntary drug treatment in Mexico is a risk factor for non-fatal drug overdose.

Non-injection Drug Use and Injection Initiation Assistance among People Who Inject Drugs in Tijuana, Mexico

Although most people who inject drugs (PWID) report receiving assistance during injection initiation events, little research has focused on risk factors among PWID for providing injection initiation assistance. We therefore sought to determine the influence of non-injection drug use among PWID on their risk to initiate others. We used generalized estimating equation (GEE) models on longitudinal data among a prospective cohort of PWID in Tijuana, Mexico (Proyecto El Cuete IV), while controlling for potential confounders. At baseline, 534 participants provided data on injection initiation assistance. Overall, 14% reported ever initiating others, with 4% reporting this behavior recently (i.e., in the past 6 months). In a multivariable GEE model, recent non-injection drug use was independently associated with providing injection initiation assistance (adjusted odds ratio [AOR] = 2.42, 95% confidence interval [CI] = 1.39-4.20). Further, in subanalyses examining specific drug types, recent non-injection use of cocaine (AOR = 9.31, 95% CI = 3.98-21.78), heroin (AOR = 4.00, 95% CI = 1.88-8.54), and methamphetamine (AOR = 2.03, 95% CI = 1.16-3.55) were all significantly associated with reporting providing injection initiation assistance. Our findings may have important implications for the development of interventional approaches to reduce injection initiation and related harms. Further research is needed to validate findings and inform future approaches to preventing entry into drug injecting.

Spatial patterns of arrests, police assault and addiction treatment center locations in Tijuana, Mexico

AIMS

In the context of a public health-oriented drug policy reform in Mexico, we assessed the spatial distribution of police encounters among people who inject drugs (PWID) in Tijuana, determined the association between these encounters and the location of addiction treatment centers and explored the association between police encounters and treatment access.

DESIGN

Geographically weighted regression (GWR) and logistic regression analysis using prospective spatial data from a community-recruited cohort of PWID in Tijuana and official geographical arrest data from the Tijuana Municipal Police Department.

SETTING

Tijuana, Mexico.

PARTICIPANTS

A total of 608 participants (median age 37; 28.4% female) in the prospective Proyecto El Cuete cohort study recruited between January and December 2011.

MEASUREMENTS

We compared the mean distance of police encounters and a randomly distributed set of events to treatment centers. GWR was undertaken to model the spatial relationship between police interactions and treatment centers. Logistic regression analysis was used to investigate factors associated with reporting police interactions.

FINDINGS

During the study period, 27.5% of police encounters occurred within 500 m of treatment centers. The GWR model suggested spatial correlation between encounters and treatment centers (global R(2)  = 0.53). Reporting a need for addiction treatment was associated with reporting arrest and police assault [adjusted odds ratio = 2.74, 95% confidence interval (CI) = 1.25-6.02, P = 0.012].

CONCLUSIONS

A geospatial analysis suggests that, in Mexico, people who inject drugs are at greater risk of being a victim of police violence if they consider themselves in need of addiction treatment, and their interactions with police appear to be more frequent around treatment centers.

Institutional stakeholder perceptions of barriers to addiction treatment under Mexico's drug policy reform

Mexico has experienced disproportionate drug-related harms given its role as a production and transit zone for illegal drugs destined primarily for the USA. In response, in 2009, the Mexican federal government passed legislation mandating pre-arrest diversion of drug-dependent individuals towards addiction treatment. However, this federal law was not specific about how the scale-up of the addiction treatment sector was to be operationalised. We therefore conducted in-depth qualitative interviews with key 'interactors' in fields affected by the federal legislation, including participants from the law enforcement, public health, addiction treatment, and governmental administration sectors. Among 19 participants from the municipal, state and federal levels were interviewed and multiple barriers to policy reform were identified. First, there is a lack of institutional expertise to implement the reform. Second, the operationalisation of the reform was not accompanied by a coordinated action plan. Third, the law is an unfunded mandate. Institutional barriers are likely hampering the implementation of Mexico's policy reform. Addressing the concerns expressed by interactors through the scale-up of services, the provision of increased training and education programmes for stakeholders and a coordinated action plan to operationalise the policy reform are likely needed to improve the policy reform process.

Polydrug Use and HIV Risk Among People Who Inject Heroin in Tijuana, Mexico: A Latent Class Analysis

BACKGROUND

Although most people who inject drugs (PWID) in Tijuana, Mexico, primarily inject heroin, injection and non-injection use of methamphetamine and cocaine is common. We examined patterns of polydrug use among heroin injectors to inform prevention and treatment of drug use and its health and social consequences.

METHODS

Participants were PWID residing in Tijuana, aged ≥18 years who reported heroin injection in the past six months and were recruited through respondent-driven sampling (n = 1,025). Latent class analysis was conducted to assign individuals to classes on a probabilistic basis, using four indicators of past six-month polydrug and polyroute use: cocaine injecting, cocaine smoking or snorting, methamphetamine injecting, and methamphetamine smoking or snorting. Latent class membership was regressed onto covariates in a multinomial logistic regression.

RESULTS

Latent class analyses testing 1, 2, 3, and 4 classes were fit, with the 3-class solution fitting best. Class 1 was defined by predominantly heroin use (50.2%, n = 515); class 2 by methamphetamine and heroin use (43.7%, n = 448), and class 3 by methamphetamine, cocaine, and heroin use (6.0%, n = 62). Bivariate and multivariate analyses indicated a group of methamphetamine and cocaine users that exhibited higher-risk sexual practices and lower heroin injecting frequency, and a group of methamphetamine users who were younger and more likely to be female.

CONCLUSIONS

Discrete subtypes of heroin PWID were identified based on methamphetamine and cocaine use patterns. These findings have identified subtypes of heroin injectors who require more tailored interventions to reduce the health and social harms of injecting drug use.

Examining negative effects of early life experiences on reproductive and sexual health among female sex workers in Tijuana, Mexico

OBJECTIVE

To explore experiences during childhood and adolescence that influenced reproductive and sexual health among women who had entered the sex industry in adolescence.

METHODS

A qualitative study was conducted using information provided by 25 female sex workers (FSWs) from Tijuana, Mexico, who reported entering the sex industry when younger than 18 years. In-depth, semi-structured interviews were conducted with all participants between January 31, 2011, and July 8, 2011.

RESULTS

Four interrelated themes that shaped health experiences-early sexual abuse, early illicit drug use, ongoing violence, and limited access to reproductive and sexual health care-were identified. Participants reporting these experiences were at risk of unintended teenaged pregnancy, spontaneous abortion or stillbirth, and untreated sexually transmitted infections.

CONCLUSION

Programs and policies that address social, structural, and individual vulnerabilities during adolescence and adulthood are required to promote reproductive and sexual health among FSWs in Tijuana, Mexico.

Correlates of injecting in an HIV incidence hotspot among substance users in Tijuana, Mexico

BACKGROUND

Substance use and HIV are growing problems in the Mexico-U.S. border city of Tijuana, a sex tourism destination situated on a northbound drug trafficking route. In a previous longitudinal study of injection drug users (IDUs), we found that >90% of incident HIV cases occurred within an 'HIV incidence hotspot,' consisting of 2.5-blocks. This study examines behavioral, social, and environmental correlates associated with injecting in this HIV hotspot.

METHODS

From 4/06 to 6/07, IDUs aged ≥18 years were recruited using respondent-driven sampling. Participants underwent antibody testing for HIV and syphilis and interviewer-administered surveys eliciting information on demographics, drug use, sexual behaviors, and socio-environmental influences. Participants were defined as injecting in the hotspot if they most frequently injected within a 3 standard deviational ellipse of the cohort's incident HIV cases. Logistic regression was used to identify individual and structural factors associated with the HIV 'hotspot'.

RESULTS

Of 1031 IDUs, the median age was 36 years; 85% were male; HIV prevalence was 4%. As bivariate analysis indicated different correlates for males and females, models were stratified by sex. Factors independently associated with injecting in the HIV hotspot for male IDUs included homelessness (AOR 1.72; 95%CI 1.14-2.6), greater intra-urban mobility (AOR 3.26; 95%CI 1.67-6.38), deportation (AOR 1.58; 95%CI 1.18-2.12), active syphilis (AOR 3.03; 95%CI 1.63-5.62), needle sharing (AOR 0.57; 95%CI 0.42-0.78), various police interactions, perceived HIV infection risk (AOR 1.52; 95%CI 1.13-2.03), and health insurance status (AOR 0.53; 95%CI 0.33-0.87). For female IDUs, significant factors included sex work (AOR 8.2; 95%CI 2.2-30.59), lifetime syphilis exposure (AOR 2.73; 95%CI 1.08-6.93), injecting inside (AOR 5.26; 95%CI 1.54-17.92), arrests for sterile syringe possession (AOR 4.87; 95%I 1.56-15.15), prior HIV testing (AOR 2.45; 95%CI 1.04-5.81), and health insurance status (AOR 0.12; 95%CI 0.03-0.59).

CONCLUSION

While drug and sex risks were common among IDUs overall, policing practices, STIs, mobility, and lack of healthcare access were correlated with injecting in this HIV transmission hotspot. Although participants in the hotspot were more aware of HIV risks and less likely to report needle sharing, interventions addressing STIs and structural vulnerabilities may be needed to effectively address HIV risk.