The emerging HIV epidemic on the Mexico-U.S. border: an international case study characterizing the role of epidemiology in surveillance and response

A socio-structural approach to preventing injection drug use initiation: rationale for the PRIMER study

BACKGROUND

Injection drug use remains a primary driver of HIV and HCV-related harms globally. However, there is a gap in efforts to prevent individuals from transitioning into injecting. People who inject drugs (PWID) play a key role in the transition of others into injecting, and while behavioral interventions have been developed to address this phenomenon, socio-structural approaches remain unexplored. To that end, we hypothesize that certain interventions designed to reduce injecting-related risk behaviors may also reduce the risk that PWID expose and introduce others into injecting. Identifying the preventive potential of existing interventions will inform broader efforts to prevent injecting and related harms.

METHODS

The Preventing Injecting by Modifying Existing Responses (PRIMER) study is a multi-country mixed methods study with an aim to investigate whether specific interventions (e.g., opioid substitution therapy, supervised injection facilities, stable housing, incarceration environments) and related factors (e.g., public injecting and gender) influence the likelihood that PWID initiate others into injecting. This study will (1) investigate the PWID participation in injection initiation; (2) identify factors influencing the risk that PWID expose others to or facilitate injection initiation; (3) describe drug scene roles that increase the risk of PWID facilitating injection initiation; and (4) evaluate the impact of structural, social, or biomedical interventions on the risk that PWID facilitate injection initiation. It does so by pooling observational data from cohort studies of PWID in six cities: Vancouver, Canada; San Diego, USA; Tijuana, Mexico; Paris, Marseille, and Bordeaux, France.

RESULTS

Team members are conducting a prospective, multi-site study of PWID (n = 3050) in North America and France that includes quantitative and qualitative data collection through four separate cohort studies of PWID (San Diego, STAHR II; Tijuana, El Cuete IV; Vancouver, V-DUS; Bordeaux, Marseille, Paris and Strasbourg, COSINUS).

CONCLUSIONS

PRIMER is the largest study of injection initiation to date and the first to investigate structural approaches to preventing injection drug use initiation. Findings have the potential to inform the development and scale up of new and existing interventions to prevent transitions into injecting.

TRIAL REGISTRATION

Preventing Injecting by Modifying Existing Responses (PRIMER), NIDA DP2-DA040256-01 .

Overlapping substance using high-risk groups and infectious diseases: how dynamic modelling can evaluate risk and target HIV prevention

It’s difficult to develop infectious disease interventions (such as for HIV) for overlapping high-risk populations such as people who inject drugs, men who have sex with men, and female sex workers, where there are multiple transmission routes. Recent advances in dynamic modelling of coinfection epidemics could disentangle the contributions of different risk groups and behaviours to help develop more efficient and effective prevention interventions.

Correlates of unprotected sex with male clients among female sex workers in 13 Mexican cities

This study examined correlates of unprotected vaginal and anal sex (UVA) with male clients among female sex workers (FSWs). Baseline data were gathered from 1089 FSWs recruited from 13 cities across Mexico enrolled in an evidence-based sexual risk reduction intervention. We used generalised estimating equations (GEE) to predict total UVA while controlling for the nested structure of the data. Total UVA with clients in the past month was examined in relation to selected sociodemographic, substance-use, and micro- and macro-environmental factors. A greater number of UVA acts was associated with three micro-level environmental factors (i.e. never getting condoms for free, unaffordability of condoms, greater number of clients per month), and three macro-level environmental factors (i.e. lower health and higher education indices, greater population size of city). These findings suggest the development of social and structural approaches to HIV prevention for FSWs in Mexico, including modification of venue-based policies that pressure FSWs to maximise client volume, changes to the work environment that promote availability and affordability of condoms, and improved population health. Moreover, our findings call for the development of context-specific HIV interventions that take into account variations in the sexual risk behaviours and HIV risk environments of FSWs throughout Mexico.

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.

Engagement in the HIV Care Continuum among Key Populations in Tijuana, Mexico

In Tijuana, Mexico, HIV is concentrated in sub-epidemics of key populations: persons who inject drugs (PWID), sex workers (SW), and men who have sex with men (MSM). To date, data on engagement in the HIV care continuum among these key populations, particularly in resource-constrained settings, are sparse. We pooled available epidemiological data from six studies (N = 3368) to examine HIV testing and treatment uptake in these key populations; finding an overall HIV prevalence of 5.7 %. Of the 191 identified HIV-positive persons, only 11.5 % knew their HIV-positive status and 3.7 % were on ART. Observed differences between these HIV-positive key populations suggest PWID (vs. non-PWID) were least likely to have previously tested or initiate HIV care. MSM (vs. non-MSM) were more likely to have previously tested but not more likely to know their HIV-positive status. Of persons aware of their HIV-positive status, SW (vs. non-SW) were more likely to initiate HIV care. Findings suggest engagement of key populations in HIV treatment is far below estimates observed for similarly resource-constrained generalized epidemics in sub-Saharan Africa. These data provide one of the first empirical-snapshots highlighting the extent of HIV treatment disparities in key populations.

In-Country Migration and Risk Factors for HIV Acquisition among Pregnant Women in Tijuana, Mexico

OBJECTIVE

To compare HIV prevalence and HIV acquisition risk behaviors between pregnant women residents and migrants.

DESIGN

A cross-sectional study of pregnant women of unknown HIV status seeking care at Tijuana General Hospital, Mexico.

METHODS

Pregnant women attending the labor and delivery unit or the prenatal clinic had a rapid HIV test drawn, with positive results confirmed by Western blot. Migrants were defined as women who had resided in Tijuana for less than 5 years.

RESULTS

Between 2007 and 2008, a total of 3331 pregnant women consented to participate. The HIV seroprevalence did not differ between Tijuana residents (18 of 2502, 0.72%) and migrants (3 of 829, 0.36%, P = .32). In multivariate regression analyses, HIV acquisition risk behaviors included methamphetamine use (adjusted odds ratio [OR]: 6.03, 95% confidence interval [CI]: 2.3-15.8, P < .001) and first presentation at labor (adjusted OR: 5.0, 95% CI: 1.6-15.3, P = .005), adjusted for migrant status, age, and history of sexually transmitted infections.

CONCLUSION

The overall HIV seroprevalence was 0.63% and did not differ between Tijuana residents and migrants.

Cost-Effectiveness of Combined Sexual and Injection Risk Reduction Interventions among Female Sex Workers Who Inject Drugs in Two Very Distinct Mexican Border Cities

Background

We evaluated the cost-effectiveness of combined single session brief behavioral intervention, either didactic or interactive (Mujer Mas Segura, MMS) to promote safer-sex and safer-injection practices among female sex workers who inject drugs (FSW-IDUs) in Tijuana (TJ) and Ciudad-Juarez (CJ) Mexico. Data for this analysis was obtained from a factorial RCT in 2008–2010 coinciding with expansion of needle exchange programs (NEP) in TJ, but not in CJ.

Methods

A Markov model was developed to estimate the incremental cost per quality adjusted life year gained (QALY) over a lifetime time frame among a hypothetical cohort of 1,000 FSW-IDUs comparing a less intensive didactic vs. a more intensive interactive format of the MMS, separately for safer sex and safer injection combined behavioral interventions. The costs for antiretroviral therapy was not included in the model. We applied a societal perspective, a discount rate of 3% per year and currency adjusted to US$2014. A multivariate sensitivity analysis was performed. The combined and individual components of the MMS interactive behavioral intervention were compared with the didactic formats by calculating the incremental cost-effectiveness ratios (ICER), defined as incremental unit of cost per additional health benefit (e.g., HIV/STI cases averted, QALYs) compared to the next least costly strategy. Following guidelines from the World Health Organization, a combined strategy was considered highly cost-effective if the incremental cost per QALY gained fell below the gross domestic product per capita (GDP) in Mexico (equivalent to US$10,300).

Findings

For CJ, the mixed intervention approach of interactive safer sex/didactic safer injection had an incremental cost-effectiveness ratio (ICER) of US$4,360 ($310–$7,200) per QALY gained compared with a dually didactic strategy. Using the dually interactive strategy had an ICER of US$5,874 ($310–$7,200) compared with the mixed approach. For TJ, the combination of interactive safer sex/didactic safer injection had an ICER of US$5,921 ($104–$9,500) per QALY compared with dually didactic. Strategies using the interactive safe injection intervention were dominated due to lack of efficacy advantage. The multivariate sensitivity analysis showed a 95% certainty that in both CJ and TJ the ICER for the mixed approach (interactive safer sex didactic safer injection intervention) was less than the GDP per capita for Mexico. The dual interactive approach met this threshold consistently in CJ, but not in TJ.

Interpretation

In the absence of an expanded NEP in CJ, the combined-interactive formats of the MMS behavioral intervention is highly cost-effective. In contrast, in TJ where NEP expansion suggests that improved access to sterile syringes significantly reduced injection-related risks, the interactive safer-sex combined didactic safer-injection was highly cost-effective compared with the combined didactic versions of the safer-sex and safer-injection formats of the MMS, with no added benefit from the interactive safer-injection component.

Risk behaviours for HIV infection among travelling Mexican migrants: The Mexico-US border as a contextual risk factor

The Mexico-US border region is a transit point in the trajectory of Mexican migrants travelling to and from the USA and a final destination for domestic migrants from other regions in Mexico. This region also represents a high-risk environment that may increase risk for HIV among migrants and the communities they connect. We conducted a cross-sectional, population-based survey, in Tijuana, Mexico, and compared Mexican migrants with a recent stay on the Mexico-US border region (Border, n = 553) with migrants arriving at the border from Mexican sending communities (Northbound, n = 1077). After controlling for demographics and migration history, border migrants were more likely to perceive their risk for HIV infection as high in this region and regard this area as a liberal place for sexual behaviours compared to Northbound migrants reporting on their perceptions of the sending communities (p < .05). Male border migrants were more likely to engage in sex, and have unprotected sex, with female sex workers during their recent stay on the border compared to other contexts (rate ratio = 3.0 and 6.6, respectively, p < .05). Binational and intensified interventions targeting Mexican migrants should be deployed in the Mexican border region to address migration related HIV transmission in Mexico and the USA.

HIV testing among men who have sex with men in Tijuana, Mexico: a cross-sectional study

OBJECTIVES

HIV testing is critical to the delivery of comprehensive HIV prevention and care services, yet coverage of sexual minorities by HIV testing programmes remains insufficient in many low- and middle-income countries, including Mexico. The objective of this study was to identify the prevalence and correlates of HIV testing among men who have sex with men (MSM) in Tijuana, Mexico.

METHODS

We conducted a cross-sectional study (2012-2013) among 189 MSM recruited via respondent-driven sampling (RDS). RDS-weighted logistic regression was used to identify correlates of prior HIV testing.

RESULTS

RDS-adjusted prevalence of prior and recent (≤ 12 months) HIV testing was 63.5% (95% CI 51.9% to 73.5%) and 36.8% (95% CI 25.4% to 46.4%), respectively. Prior HIV testing was positively associated with older age (adjusted OR (AOR)=1.09, 95% CI 1.04 to 1.15), being born in Tijuana (AOR=2.68, 95% CI 1.05 to 6.86), higher levels of education (AOR=2.65, 95% CI 1.08 to 6.53), identifying as homosexual or gay (AOR=3.73, 95% CI 1.48 to 9.42), being more 'out' about having sex with men (AOR=1.28, 95% CI:1.02 to 1.62), and a history of sexual abuse (AOR=3.24, 95% CI 1.06 to 9.86). Prior HIV testing was negatively associated with reporting more condomless anal intercourse acts (past 2 months) (AOR=0.95, 95% CI 0.92 to 0.98) and greater internalised homophobia (AOR=0.92, 95% CI 0.86 to 0.99).

CONCLUSIONS

Our findings indicate an urgent need for expanded HIV testing services for MSM in Tijuana. Innovative, non-stigmatising, confidential HIV testing interventions targeted at young, less educated, migrant and non-gay identifying MSM may facilitate HIV testing and timely linkage to HIV care and treatment within this population.

Predictors of Injection Cessation and Relapse among Female Sex Workers who Inject Drugs in Two Mexican-US Border Cities

We know little about predictors of injection drug cessation and relapse among female sex workers who inject drugs (FSW-PWID) at the US-Mexico border. Among HIV-negative FSW-PWID taking part in a behavioral intervention study in Tijuana and Ciudad Juárez, Cox regression was used to identify predictors of time to first cessation of injection, which was defined as reporting not having injected drugs for a period of 4 months or longer, and among that subset, we examined predictors of time to injection relapse. Among 440 women, 84 (19%) reported ceasing injection during follow-up (median time to cessation = 9.3 months); of these, 30 (35%) reported relapse to injection (median time to relapse = 3.5 months). The rate of injection cessation was lower for women reporting trading sex prior to age 18 (adj. hazard ratio (HR) = 0.64, 95% confidence interval (CI) = 0.41-1.01), ever being sexually abused (adj. HR = 0.44, 95% CI = 0.27-0.71), and a higher number of vaginal sex acts with casual clients (adj. HR = 0.99 per transaction, 95% CI = 0.98-1.00). The rate of cessation was higher for women who spent more hours on the streets on a typical day (adj. HR = 1.04/h, 95% CI = 1.01-1.08) and who lived in Tijuana vs. Ciudad Juárez (adj. HR = 2.15, 95% CI = 1.14-4.07). The rate of relapse was higher among women reporting regular drug use with clients (adj. HR = 2.17, 95% CI = 0.96-4.89) and those scoring higher on a risk injection index (adj. HR = 2.04, 95% CI = 1.15-3.61). The rate of relapse was lower for FSW-PWID with higher than average incomes (adj. HR = 0.40, 95% CI = 0.18-0.89). These findings have important implications for the scale-up of methadone maintenance treatment programs (MMTPs) in Mexico and indicate a need for gender-specific programs that address sexual abuse experiences and economic vulnerabilities faced by FSW-PWID.

Predictors of needle exchange program utilization during its implementation and expansion in Tijuana, Mexico

OBJECTIVE

Until the early 2000s, there was only one needle exchange program (NEP) offered in Mexico. In 2004, the second Mexican NEP opened in Tijuana, but its utilization has not been studied. We studied predictors of initiating NEP during its early expansion in Tijuana, Mexico.

METHODS

From April 2006 to April 2007, people who inject drugs (PWID) residing in Tijuana who had injected within the last month were recruited using respondent-driven sampling. Weighted Poisson regression incorporating generalized estimating equations was used to identify predictors of initiating NEP, while accounting for correlation between recruiter and recruits.

RESULTS

NEP uptake increased from 20% at baseline to 59% after 6 months. Among a subsample of PWID not accessing NEP at baseline (n = 480), 83% were male and median age was 37 years (Interquartile Range: 32-43). At baseline, 4.4% were HIV-infected and 5.9% had syphilis titers >1:8. In multivariate models, factors associated with NEP initiation (p < .05) were attending shooting galleries (Adjusted Relative Risk [ARR]: 1.54); arrest for track-marks (ARR: 1.38); having a family member that ever used drugs (ARR: 1.37); and having a larger PWID network (ARR: 1.01 per 10 persons). NEP initiation was inversely associated with obtaining syringes at pharmacies (ARR: .56); earning >2500 pesos/month (ARR: .66); and reporting needle sharing (ARR: .71).

CONCLUSIONS

Uptake of NEP expansion in Tijuana was vigorous among PWID. We identified a range of factors that influenced the likelihood of NEP initiation, including police interaction. These findings have important implications for the scale-up of NEP in Mexico.

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.

Prevalence and Correlates of Client-Perpetrated Violence against Female Sex Workers in 13 Mexican Cities

BACKGROUND

Globally, client-perpetrated violence against female sex workers (FSWs) has been associated with multiple health-related harms, including high-risk sexual behavior and increased exposure to HIV/STIs. This study examined correlates of client-perpetrated sexual, physical, and economic violence (e.g., robbery) against FSWs in 13 cities throughout Mexico.

METHODS

FSWs (N = 1,089) who were enrolled in a brief, evidence-based, sexual risk reduction intervention for FSWs (Mujer Segura) were interviewed about their work context, including experiences of violence perpetrated by clients, sexual risk and substance use practices, financial need, and social supports. Three broad categories of factors (sociodemographic, work context, behavioral and social characteristics of FSWs) were examined as correlates of sexual, physical, and economic violence.

RESULTS

The prevalence of different types of client-perpetrated violence against FSWs in the past 6 months was: sexual (11.7%), physical (11.8%), economic (16.9%), and any violence (22.6%). Greater financial need, self-identification as a street worker, and lower perceived emotional support were independently associated with all three types of violence. Alcohol use before or during sex with clients in the past month was associated with physical and sexual violence. Using drugs before or during sex with clients, injection drug use in the past month, and population size of city were associated with sexual violence only, and FSWs' alcohol use score (AUDIT-C) was associated with economic violence only.

CONCLUSIONS

Correlates of client-perpetrated violence encompassed sociodemographic, work context, and behavioral and social factors, suggesting that approaches to violence prevention for FSWs must be multi-dimensional. Prevention could involve teaching FSWs strategies for risk avoidance in the workplace (e.g., avoiding use of alcohol with clients), enhancement of FSWs' community-based supports, development of interventions that deliver an anti-violence curriculum to clients, and programs to address FSWs' financial need by increasing their economic opportunities outside of the sex trade.

HIV Drug Resistance Surveillance in Honduras after a Decade of Widespread Antiretroviral Therapy

Introduction

We assessed HIV drug resistance (DR) in individuals failing ART (acquired DR, ADR) and in ART-naïve individuals (pre-ART DR, PDR) in Honduras, after 10 years of widespread availability of ART.

Methods

365 HIV-infected, ART-naïve, and 381 ART-experienced Honduran individuals were enrolled in 5 reference centres in Tegucigalpa, San Pedro Sula, La Ceiba, and Choluteca between April 2013 and April 2015. Plasma HIV protease-RT sequences were obtained. HIVDR was assessed using the WHO HIVDR mutation list and the Stanford algorithm. Recently infected (RI) individuals were identified using a multi-assay algorithm.

Results

PDR to any ARV drug was 11.5% (95% CI 8.4–15.2%). NNRTI PDR prevalence (8.2%) was higher than NRTI (2.2%) and PI (1.9%, p<0.0001). No significant trends in time were observed when comparing 2013 and 2014, when using a moving average approach along the study period or when comparing individuals with >500 vs. <350 CD4+ T cells/μL. PDR in recently infected individuals was 13.6%, showing no significant difference with PDR in individuals with longstanding infection (10.7%). The most prevalent PDR mutations were M46IL (1.4%), T215 revertants (0.5%), and K103NS (5.5%). The overall ADR prevalence in individuals with <48 months on ART was 87.8% and for the ≥48 months on ART group 81.3%. ADR to three drug families increased in individuals with longer time on ART (p = 0.0343). M184V and K103N were the most frequent ADR mutations. PDR mutation frequency correlated with ADR mutation frequency for PI and NNRTI (p<0.01), but not for NRTI. Clusters of viruses were observed suggesting transmission of HIVDR both from ART-experienced to ART-naïve individuals and between ART-naïve individuals.

Conclusions

The global PDR prevalence in Honduras remains at the intermediate level, after 10 years of widespread availability of ART. Evidence of ADR influencing the presence of PDR was observed by phylogenetic analyses and ADR/PDR mutation frequency correlations.

Network Characteristics of People Who Inject Drugs Within a New HIV Epidemic Following Austerity in Athens, Greece

BACKGROUND

Greece experienced an unprecedented increase in HIV cases among drug injectors in 2011 after economic crisis. Network-level factors are increasingly understood to drive HIV transmission in emerging epidemics.

METHODS

We examined the relationship between networks, risk behaviors, and HIV serostatus among 1404 people who inject drugs in Athens, Greece. We generated networks using the chain-referral structure within a large HIV screening program. Network proportions, the proportion of a respondent's network with a given characteristic, were calculated. Multiple logistic regression models were used to assess the relationship between network proportions and individual HIV seroprevalence, injection frequency and unprotected sex.

RESULTS

Of note, 1030 networks were generated. Respondent HIV seroprevalence was associated with greater proportions of network members who were HIV infected (ie, those with ≥ 50% of network members HIV positive vs. those with no network members HIV positive) (AOR: 3.11; 95% CI: 2.10 to 4.62), divided drugs (AOR: 1.60; 95% CI: 1.10 to 2.35), or injected frequently (AOR: 1.50; 95% CI: 1.02 to 2.21). Homelessness was the only sociodemographic characteristic associated with a risk outcome measure--high-frequency injecting (AOR: 1.41; 95% CI: 1.03 to 1.93). These associations were weaker for more distal second- and third-degree networks and not present when examined within random networks.

CONCLUSIONS

Networks are an independently important contributor to the HIV outbreak in Athens, Greece. Network associations were strongest for the immediate network, with residual associations for distal networks. Homelessness was associated with high-frequency injecting. Prevention programs should consider including network-level interventions to prevent future emerging epidemics.

Behavioral and psychosocial correlates of anal sex among male clients of female sex workers in Tijuana, Mexico

Most studies of heterosexual sex risk practices have focused on condomless vaginal sex despite evidence that condomless anal sex has a significantly higher risk of HIV transmission. The present study focused on male clients' anal sex practices with female sex workers (FSWs) in Tijuana, Mexico, where an HIV epidemic is growing among high-risk groups. Logistic regression analyses were used to identify psychosocial and behavioral correlates of anal sex among male clients. Our sample of HIV-negative men (N = 400) was predominantly Latino (87.5 %), born in Mexico (78.8 %), never married (36.8 %) or in a regular or common-law marriage (31.5 %), and employed (62.8 %), with an average age and education of 37.8 and 9.2 years, respectively. Eighty-nine percent identified as heterosexual and 11 % as bisexual. By design, 50 % of the sample resided in Tijuana and the other 50 % in San Diego County. Nearly half (49 %) reported at least one incident of anal sex with a FSW in Tijuana in the past 4 months; of those participants, 85 % reported that one or more of their anal sex acts with FSWs had been without a condom. In a multivariate model, anal sex with a FSW in the past 4 months was associated with bisexual identification, methamphetamine use with FSWs, repeat visits to the same FSW, higher scores on perceived stigma about being a client of FSWs, and sexual compulsivity. Prevention programs are needed that address the behavioral and psychosocial correlates of heterosexual anal sex in order to reduce HIV/STI transmission risk among male clients, FSWs, and their sexual network members.

Prevalence and correlates of neck injection among people who inject drugs in Tijuana, Mexico

INTRODUCTION AND AIMS

Injecting drugs in the neck has been related to adverse health conditions such as jugular vein thrombosis, deep neck infections, aneurysm, haematomas, airway obstruction, vocal cord paralysis and wound botulism, among others. We identified prevalence and correlates of neck injection among people who inject drugs (PWID) in Tijuana, Mexico.

DESIGN AND METHODS

Beginning in 2011, PWID aged ≥18 years who injected drugs within the last month were recruited into a prospective cohort. At baseline and semi-annually, PWID completed interviewer-administered surveys soliciting data on drug-injecting practices. Logistic regression was used to identify predictors of injecting in the neck as the most frequent injection site at a single visit.

RESULTS

Of 380 PWID, 35.3% injected in the neck at least once in the past 6 months, among whom 71.6% reported it as their most common injection site, the most common injecting site after the arms (47%). Controlling for age, years injecting and injecting frequency, injecting heroin and methamphetamine two or more times per day and having sought injection assistance were associated with injecting in the neck [adjusted odds ratios (AOR): 2.12; 95% confidence intervals (CI): 1.27-3.53 and AOR: 2.65; 95% CI: 1.52-4.53 respectively].

DISCUSSION AND CONCLUSIONS

Injecting in the neck was very common among PWID in Tijuana and was associated with polydrug use and seeking injection assistance. Tailoring harm reduction education interventions for individuals who provide injection assistance ('hit doctors') may allow for the dissemination of safe injecting knowledge to reduce injection-related morbidity and mortality.

Examining the spatial distribution of law enforcement encounters among people who inject drugs after implementation of Mexico's drug policy reform

In 2009, Mexico decriminalized the possession of small amounts of illicit drugs for personal use in order to refocus law enforcement resources on drug dealers and traffickers. This study examines the spatial distribution of law enforcement encounters reported by people who inject drugs (PWID) in Tijuana, Mexico to identify concentrated areas of policing activity after implementation of the new drug policy. Mapping the physical location of law enforcement encounters provided by PWID (n = 461) recruited through targeted sampling, we identified hotspots of extra-judicial encounters (e.g., physical/sexual abuse, syringe confiscation, and money extortion by law enforcement) and routine authorized encounters (e.g., being arrested or stopped but not arrested) using point density maps and the Getis-Ord Gi* statistic calculated at the neighborhood-level. Approximately half of the participants encountered law enforcement more than once in a calendar year and nearly one third of these encounters did not result in arrest but involved harassment or abuse by law enforcement. Statistically significant hotspots of law enforcement encounters were identified in a limited number of neighborhoods located in areas with known drug markets. At the local-level, law enforcement activities continue to target drug users despite a national drug policy that emphasizes drug treatment diversion rather than punitive enforcement. There is a need for law enforcement training and improved monitoring of policing tactics to better align policing with public health goals.

Migrants in transit: the importance of monitoring HIV risk among migrant flows at the Mexico-US border

We conducted a probability-based survey of migrant flows traveling across the Mexico-US border, and we estimated HIV infection rates, risk behaviors, and contextual factors for migrants representing 5 distinct migration phases. Our results suggest that the influence of migration is not uniform across genders or risk factors. By considering the predeparture, transit, and interception phases of the migration process, our findings complement previous studies on HIV among Mexican migrants conducted at the destination and return phases. Monitoring HIV risk among this vulnerable transnational population is critical for better understanding patterns of risk at different points of the migration process and for informing the development of protection policies and programs.

Police bribery and access to methadone maintenance therapy within the context of drug policy reform in Tijuana, Mexico

AIMS

In 2009, Mexico passed legislation to decriminalize drug possession and improve access to addiction treatment. We undertook research to assess the implementation of the reform among a cohort of people who inject drugs (PWID) in Tijuana. This study specifically sought to determine whether discretionary policing practices like extortion impact access to methadone maintenance therapy (MMT) in Tijuana, a city characterized by high levels of drug-related harms.

METHODS

Generalized estimating equation analyses were used to construct longitudinal confounding models to determine the association between paying a police bribe and MMT enrolment among PWID in Tijuana enrolled in a prospective cohort study. Outcome of interest was MMT enrolment in the past six months. Data on police interactions and MMT enrolment were also obtained.

RESULTS

Between October, 2011 and September, 2013, 637 participants provided 1825 observations, with 143 (7.8%) reports of MMT enrolment during the study period. In a final confounding model, recently reporting being forced to pay a bribe to police was significantly associated with an increased likelihood of accessing MMT (adjusted odds ratio=1.69, 95% confidence interval: 1.02-2.81, p=0.043). However, in 56 (39.2%) cases, MMT enrolment ceased within six months. The majority of participant responses cited the fact that MMT was too expensive (69.1%).

DISCUSSION

Levels of MMT access were low. PWID who experienced police extortion were more likely to access MMT at baseline, though this association decreased during the study period. Coupled with the costs of MMT, this may compromise MMT retention among PWID.

High dead-space syringe use among people who inject drugs in Tijuana, Mexico

BACKGROUND

High dead-space syringes (HDSS) are believed to confer an elevated risk of acquiring HIV and other blood-borne infections.

OBJECTIVES

We identified prevalence and correlates of HDSS use among injection drug users (IDU) in Tijuana, Mexico, where syringe purchase and possession is legal without a prescription.

METHODS

Beginning in 2011, IDU who reported being 18 years or older and injected drugs within the last month were recruited into a prospective study. At baseline and semi-annually, 557 IDU underwent HIV-testing and interviewer-administered surveys. Logistic regression was used to identify correlates of using HDSS.

RESULTS

Of 557 IDU, 40% had ever used HDSS, mostly because no other syringe type was available (72%), or because they were easier to get (20%). Controlling for sex and age at first injection, use of HDSS was associated with cocaine as the first drug injected (Adjusted Odds Ratio [AOR]: 2.68; Confidence Interval 95% [CI]: 1.15-6.22), having been stopped or arrested by police (AOR: 1.84; 95% CI: 1.11-3.07), being deported from the US (AOR: 1.64; 95% CI:1.06-2.53), and believing it is illegal to carry syringes (AOR:1.78; 95% CI: 1.01-3.15).

CONCLUSION

Use of HDSS is surprisingly common among IDU in Tijuana. Efforts are needed to expand coverage of low-dead space syringes through existing syringe exchange programs. Education is required to increase awareness of the harms associated with HDSS, and to inform IDU that syringe possession is legal across Mexico.

Prevalence and correlates of HIV among men who have sex with men in Tijuana, Mexico

Introduction

Men who have sex with men (MSM) in developing countries such as Mexico have received relatively little research attention. In Tijuana, Mexico, a border city experiencing a dynamic HIV epidemic, data on MSM are over a decade old. Our aims were to estimate the prevalence and examine correlates of HIV infection among MSM in this city.

Methods

We conducted a cross-sectional study of 191 MSM recruited through respondent-driven sampling (RDS) in 2012. Biological males over the age of 18 who resided in Tijuana and reported sex with a male in the past year were included. Participants underwent interviewer-administered surveys and rapid tests for HIV and syphilis with confirmation.

Results

A total of 33 MSM tested positive for HIV, yielding an RDS-adjusted estimated 20% prevalence. Of those who tested positive, 89% were previously unaware of their HIV status. An estimated 36% (95% CI: 26.4–46.5) had been tested for HIV in the past year, and 30% (95% CI: 19.0–40.0) were estimated to have ever used methamphetamine. Independent correlates of being infected with HIV were methamphetamine use (odds ratio [OR]=2.24, p=0.045, 95% CI: 1.02, 4.92) and active syphilis infection (OR=4.33, p=0.01, 95% CI: 1.42, 13.19).

Conclusions

Our data indicate that MSM are a key sub-population in Tijuana at higher risk for HIV. Tijuana would also appear to have the highest proportion among upper-middle-income countries of HIV-positive MSM who are unknowingly infected. More HIV prevention research on MSM is urgently needed in Tijuana.

Incident syphilis infection among people who inject drugs in Tijuana, Mexico

Given that syphilis is associated with HIV infection among people who inject drugs (PWID), we examined syphilis incidence among PWID in Tijuana, Mexico. From 2006 to 2007, 940 PWID (142 women and 798 men) were recruited via respondent-driven sampling and followed for 18 months. At semi-annual visits, participants were tested for syphilis and completed surveys, which collected information on socio-demographics, sexual behaviours, substance use and injection behaviours. Poisson regression was used to estimate syphilis incidence rates (IRs), incidence rate ratios (IRRs) and 95% confidence intervals (CIs). Twenty-one participants acquired syphilis during follow-up (IR = 1.57 per 100 person-years, 95% CI: 1.02-2.41). In a multivariate analysis, syphilis incidence was higher among women (IRR = 3.90, 95% CI: 1.37-11.09), HIV-positive participants (IRR = 4.60, 95% CI: 1.58-13.39) and those who reported ever exchanging sex for drugs, money, or other goods (IRR = 2.74, 95% CI: 0.97-7.76), while syphilis incidence was lower among those living in Tijuana for a longer duration (IRR = 0.95 per year, 95% CI: 0.91-1.00) and those reporting at least daily injection drug use (past 6 months) (IRR = 0.22, 95% CI: 0.09-0.54). Our findings suggest interventions that address the destabilising conditions associated with migration and integrate sexual and drug-related risk reduction strategies may help reduce syphilis incidence among PWID along the Mexico-US border.

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.

Epidemiology of HIV in Latin America and the Caribbean

PURPOSE OF REVIEW

The aim of the present review is to update HIV/AIDS Epidemiology in Latin America and the Caribbean highlighting the concentrated aspect of epidemic in the region.

RECENT FINDINGS

Among general population, HIV prevalence in Latin America is at stable levels (0.2-0.7%). The Caribbean still has one of the highest HIV prevalence rates in the world (<0.1-3%), but incidences have declined around 49%. This is not the current situation for high-risk key populations; most incident cases occur among MSM. Available data on transgender women suggest that they are the most-at-risk group. Female sex workers still have a 12-fold the chance of being HIV positive compared with other women. IDU prevalence was revised to 0.45%, but non-IDU has been suggested as a mediator between sexual risk and HIV.

SUMMARY

The increase in treatment coverage (mean is at 63%) resulted in modifications of HIV/AIDS epidemiology. New strategies to seek, test and link key populations to care are urgently needed and targeted interventions to prevent HIV expansion among them must be adopted. These strategies should consider the particular situation regarding social inequalities, discrimination and violence that pervade the HIV epidemic among key populations.

Dose-response association between salivary cotinine levels and Mycobacterium tuberculosis infection

SETTING

Tijuana, Mexico.

OBJECTIVE

To describe the association between salivary cotinine levels and interferon-gamma (IFN-γ) release assay results.

DESIGN

We conducted a cross-sectional study among injection drug users. Salivary cotinine levels were measured using NicAlert, a semi-quantitative dipstick assay. QuantiFERON©-TB Gold In-Tube (QFT-GIT) was used to determine Mycobacterium tuberculosis infection.

RESULTS

Among 234 participants, the prevalence of QFT-GIT positivity for NicAlert cotinine categories 0 (non-smoking), 1 (second-hand smoke exposure or low-level smoking) and 26 (regular smoking) were respectively 42.1%, 46.4% and 65.2% (Ptrend 0.012). We found increasing trends in QFT-GIT positivity (Ptrend 0.003) and IFN-γ concentrations (Spearman's r 0.200, P 0.002) across cotinine levels 0 to 6. In multivariable log-binomial regression models adjusted for education, cotinine levels were not associated with QFT-GIT positivity when included as smoking categories (1 and 26 vs. 0), but were independently associated with QFT-GIT positivity when included as an ordinal variable (prevalence ratio 1.09 per 1 cotinine level, 95%CI 1.021.16).

CONCLUSION

Our findings suggest that a dose-response relationship exists between tobacco smoke exposure and M. tuberculosis infection. Longitudinal studies that use biochemical measures for smoking status are needed to confirm our findings.

Mexicans' use of illicit drugs in an era of drug reform: national comparative analysis by migrant status

BACKGROUND

Although rates of illicit drug use are considerably lower in Mexico than in the United States, rates in Mexico have risen significantly. This increase has particular implications for Mexican women and US migrants, who are considered at increased risk of drug use. Due to drug reforms enacted in Mexico in 2008, it is critical to evaluate patterns of drug use among migrants who reside in both regions.

METHODS

We analysed a sample of Mexicans (N=16,249) surveyed during a national household survey in 2011, the Encuesta Nacional de Adicciones (National Survey of Addictions). Comparative analyses based on Mexicans' migrant status - (1) never in the United States, (2) visited the United States, or (3) lived in the United States (transnationals) - featured analysis of variance and Chi-square global tests. Two multilevel regressions were conducted to determine the relationships among migrant status, women, and illicit drug use.

RESULTS

Comparative findings showed significant differences in type and number of drugs used among Mexicans by migrant status. The regression models showed that compared with Mexicans who had never visited the United States, Mexican transnationals were more likely to report having used drugs (OR=2.453, 95% CI=1.933, 3.113) and using more illicit drugs (IRR=2.061, 95% CI=1.626, 2.613). Women were less likely than men to report having used drugs (OR=0.187, 95% CI=0.146, 0.239) and using more illicit drugs (IRR=0.153, 95% CI=0.116, 0.202).

CONCLUSIONS

Overall, the findings support further exploration of risk factors for illicit drug use among Mexican transnationals, who exhibit greater drug use behaviours than Mexicans never in the United States. Because drug reform mandates referrals to treatment for those with recurrent issues of drug use, it is critical for the Mexican government and civic society to develop the capacity to offer evidence-based substance abuse treatment for returning migrants with high-risk drug behaviours.

A binational overview of reproductive health outcomes among US Hispanic and Mexican women in the border region

INTRODUCTION

The US-Mexico border region has 15 million residents and 300,000 births annually. Reproductive health concerns have been identified on both sides of the border, but comparable information about reproductive health is not available. The objective of this study was to compare reproductive health indicators among populations in this region.

METHODS

We used 2009 US Hispanic and Mexican birth certificate data to compare births inside the border region, elsewhere within the border states, and in the United States and Mexico overall. We examined trends in total fertility and birth rates using birth data from 2000 through 2009 and intercensal population estimates.

RESULTS

Among women in the border region, US women had more lifetime births than Mexican women in 2009 (2.69 births vs 2.15 births) and throughout the decade. Birth rates in the group aged 15 to 19 years were high in both the US (73.8/1,000) and Mexican (86.7/1,000) border regions. Late or no prenatal care was nearly twice as prevalent in the border regions as in the nonborder regions of border states. Low birth weight and preterm and early-term birth were more prevalent in the US border than in the Mexican border region; US border rates were higher and Mexican rates were lower than their corresponding nonborder and national rates. We found some variations within border states.

CONCLUSION

These findings constitute the first population-based information on the reproductive health of the entire Hispanic US-Mexico border population. Evidence of disparities warrants exploration at state and local levels. Teen pregnancy and inadequate prenatal care are shared problems in US-Mexico border communities and suggest an area for binational cooperation.

Cigarette smoking and quit attempts among injection drug users in Tijuana, Mexico

INTRODUCTION

Injection drug use and cigarette smoking are major global health concerns. Limited data exist regarding cigarette smoking behavior and quit attempts among injection drug users (IDUs) in low- and middle-income countries to inform the development of cigarette smoking interventions. We conducted a cross-sectional study to describe cigarette smoking behavior and quit attempts among IDUs in Tijuana, Mexico.

METHODS

IDUs were recruited through community outreach and administered in-person interviews. Multivariable Poisson regression models were constructed to determine prevalence ratios (PRs) for quit attempts.

RESULTS

Of the 670 participants interviewed, 601 (89.7%) were current smokers. Of these, median number of cigarettes smoked daily was 10; 190 (31.6%) contemplated quitting smoking in the next 6 months; 132 (22.0%) had previously quit for ≥1 year; and 124 (20.6%) had made a recent quit attempt (lasting ≥1 day during the previous 6 months). In multivariable analysis, recent quit attempts were positively associated with average monthly income (≥3,500 pesos [US$280] vs. <1,500 pesos [US$120]; PR = 2.30; 95% CI = 1.57-3.36), smoking marijuana (PR = 1.38; 95% CI = 1.01-2.90), and smoking heroin (PR = 1.85; 95% CI = 1.23-2.78), and they were negatively associated with number of cigarettes smoked daily (PR = 0.96; 95% CI = 0.94-0.98).

CONCLUSIONS

One out of 5 IDUs attempted to quit cigarette smoking during the previous 6 months. Additional research is needed to improve the understanding of the association between drug use patterns and cigarette smoking quit attempts, including the higher rate of quit attempts observed among IDUs who smoke marijuana or heroin compared with IDUs who do not smoke these substances.

HIV prevention among women in low- and middle-income countries: intervening upon contexts of heightened HIV risk

Women's vulnerability to HIV infection is influenced by contextual factors in the risk environment that operate at multiple levels (i.e., physical, social, economic, policy). We present three case studies that illustrate combination approaches to HIV prevention among women who are at heightened risk for infection, especially sex workers, in low- and middle-income countries (LMICs). Lessons learned from these case studies are consistent with international literature promoting interventions that combine sexual risk reduction, condom promotion, and improved access to sexually transmitted infection (STI) treatment in the context of structural interventions, including policy change and empowerment of sex workers to reduce their vulnerability to HIV/STIs. We suggest avenues for future research and new intervention targets as well as a more nuanced approach to understanding the structural and social vulnerability of women to HIV infection in these settings.

Reducing harm from HIV/AIDS misconceptions among female sex workers in Tijuana and Ciudad Juarez, Mexico: A cross sectional analysis

Background

HIV prevalence is increasing among female sex workers (FSWs) in Mexico’s Northern border region, who experience multiple occupational risks. Improving vulnerable populations’ education, empowerment, and access to preventive services are important components of harm reduction strategies. Given the increasing interest in adapting harm reduction principles from drug use to sex work and other public health responses to the HIV epidemic, we used a sex work harm reduction framework to guide our investigation of FSWs’ HIV knowledge.

Methods

From 2004–2006, FSWs aged ≥18 years in Tijuana and Ciudad Juarez participated in a behavioral intervention study and completed structured interviews. Measures included HIV knowledge assessment and factors within each domain of our theoretical framework for sex work harms: (1) socio-demographic factors that may lead to sex work, (2) sex work characteristics and behaviors that may lead to harm, and (3) mutually reinforcing harms that lead to sex work and result from it (e.g., drug abuse). Negative binomial regression identified factors independently associated with suboptimal HIV knowledge (i.e., incorrect responses during the HIV knowledge assessment).

Results

Among 924 FSWs, the median proportion of incorrect responses was nearly one third (28% incorrect). Examination of item responses revealed misconceptions regarding specific transmission and prevention mechanisms, including prevention of mother to child transmission. Suboptimal HIV knowledge was independently associated with older age, lower education, living in Tijuana (vs. Ciudad Juarez), inconsistent condom use for vaginal sex with male clients, and lacking prior HIV testing.

Conclusions

Our application of a sex work harm reduction framework to the study of FSWs’ HIV knowledge is an important first step in enhancing HIV prevention efforts in Northern Mexican border cities. Our findings imply that interventions should identify and discredit local HIV misconceptions to improve knowledge of specific HIV transmission routes and self-protective strategies (e.g., condom negotiation). Interventions will require materials appropriate for women from diverse socio-economic backgrounds and may benefit from innovative harm reduction approaches such as peer education and outreach.