The opioid crisis and HIV in the USA: deadly synergies.

The opioid epidemic is one of the greatest public health problems that the USA faces. Opioid overdose death rates have increased steadily for more than a decade and doubled in 2013-17, as the highly potent synthetic opioid fentanyl entered the drug supply. Demographics of new HIV diagnoses among people who inject drugs are also changing, with more new HIV diagnoses occurring among White people, young people (aged 13-34 years), and people who reside outside large central metropolitan areas. Racial differences also exist in syringe sharing, which decreased among Black people and Hispanic people but remained unchanged among White people in 2005-15. Recent HIV outbreaks have occurred in rural areas of the USA, as well as among marginalised people in urban areas with robust HIV prevention and treatment services (eg, Seattle, WA). Multiple evidence-based interventions can effectively treat opioid use disorder and prevent HIV acquisition. However, considerable barriers exist precluding delivery of these solutions to many people who inject drugs. If the USA is serious about HIV prevention among this group, stigma must be eliminated, discriminatory policies must change, and comprehensive health care must be accessible to all. Finally, root causes of the opioid epidemic such as hopelessness need to be identified and addressed.

Human Immunodeficiency Virus Testing, Diagnosis, Linkage to Care, and Prevention Services Among Persons Who Inject Drugs, United States, 2012-2017.

BACKGROUND: Human immunodeficiency virus (HIV) testing and early diagnosis is associated with effective disease management and reduction in HIV transmission among persons who inject drugs (PWID). We examined trends in HIV testing outcomes among PWID during 2012-2017. METHODS: Centers for Disease Control and Prevention (CDC)-funded HIV testing data submitted by 61 health departments and 150 directly-funded community-based organizations during 2012-2017 were analyzed. We calculated estimated annual percentage changes (EAPC) to assess trends for HIV testing and testing outcomes. RESULTS: A total of 19 739 857 CDC-funded HIV tests were conducted during 2012-2017. Of these, 529 349 (2.7%) were among PWID. The percentage of newly diagnosed HIV increased from .7% in 2012 to .8% in 2017 (EAPC, 4.15%). The percentage interviewed for partner services increased from 46.7% in 2012 to 66.3% in 2017 (EAPC, 1.81%). No significant change was identified in trends for linkage to HIV medical care ≤90 days after diagnosis (EAPC, 0.52%) or referral to HIV prevention services (EAPC, 0.98%). CONCLUSIONS: Human immunodeficiency virus testing data revealed an increasing trend in newly diagnosed HIV among PWID but not linkage to HIV medical care or referral to prevention services. Expanding efforts to increase HIV testing and enhance linkage to services can lead to reductions in HIV transmission and improved health outcomes.

Serious Mental Illness Among Young People Who Inject Drugs: An Assessment of Injection Risks and Healthcare Use.

BACKGROUND: Data on behavioral correlates of mental illness among young people who inject drugs (PWID) are limited. We examine injection risks and healthcare use among young PWID with probable serious mental illness (PSMI). METHODS: People who inject drugs were recruited and interviewed in 20 US cities for 2015 National HIV Behavioral Surveillance. Probable serious mental illness was assessed using the Kessler-6 screening scale. Bivariate analyses using log-linked Poisson regression with generalized estimating equations adjusted for design covariates were conducted to examine associations between PSMI and behaviors among PWID ages 18-29 years. RESULTS: Of 1769 young PWID, 45% had PSMI. Compared to those without PSMI, PWID with PSMI were more likely to report injecting more than once a day, receptive syringe sharing, sharing of other injection equipment, and unmet needs for medical care and substance use disorder (SUD) treatment. Those with PSMI were less likely to use syringe services programs than those without PSMI. CONCLUSIONS: Approximately half of young PWID had PSMI. People who inject drugs with PSMI engaged in high-risk injection behaviors and encountered barriers to healthcare. Human immunodeficiency virus prevention programs such as Syringe Services Programs (SSPs) could benefit from screening for mental illness among young PWID and strong linkage to healthcare, including mental health and SUD treatment.

Longitudinal Factors Associated with Used Syringe Lending Among HIV-Positive Antiretroviral Therapy-Naïve People Who Inject Drugs in a Canadian Setting.

Sharing used syringes is an important route of HIV transmission, however, factors shaping used syringe-lending among antiretroviral therapy (ART)-naïve HIV-positive people who inject drugs (PWID) are not well-characterized. Multivariable logistic regression analyses using generalized estimating equations (GEE) were employed to investigate correlates of used syringe lending among ART-naïve PWID. Data was drawn from ACCESS, a prospective community-recruited cohort of HIV-positive illicit drug users in Vancouver, Canada, from 1996 to 2015. The analysis included 482 ART-naïve PWID, of which 116 (24.1%) reported ≥ 1 periods of used syringe lending. In longitudinal analyses, incarceration (Adjusted Odds Ratio [AOR] = 2.18, 95% Confidence Interval [CI] 1.48-3.20), daily cocaine injection (AOR= 1.97, 95% CI 1.33-2.90), and sex work (AOR = 1.61, 95% CI 1.02-2.55) during the 180-day observation period were positively associated with used syringe lending, while having a high school diploma (AOR = 0.63, 95% CI 0.43-0.93) and holding formal employment (AOR = 0.20, 95% CI 0.05-0.82) were negatively associated. We found a high prevalence of used syringe lending among ART-naïve HIV-positive PWID, particularly among those recently incarcerated, involved in sex work or who injected cocaine frequently. Conversely, markers of higher socio-economic status were negatively associated with used syringe lending. These findings highlight the critical need for policies and interventions to decrease socio-economic marginalization and criminalization among PWID living with HIV alongside the scale up of access to harm reduction services.

Correlates of Transactional Sex Among a Rural Population of People Who Inject Drugs.

In the United States, high rates of HIV infection among persons who engage in transactional sex are partially driven by substance use. Little is known about transactional sex among rural populations of people who inject drugs (PWID). Using data from a 2018 survey of 420 rural PWID in West Virginia, we used logistic regression to identify correlates of recent transactional sex (past 6 months). Most study participants were male (61.2%), white (83.6%), and reported having injected heroin (81.0%) in the past 6 months. Nearly one-fifth (18.3%) reported engaging in recent transactional sex. Independent correlates of transactional sex were: being female [adjusted odds ratio (aOR) 3.90; 95% CI 2.12-7.16]; being a sexual minority (aOR 3.07; 95% CI 1.60-5.87); being single (aOR 3.22; 95% CI 1.73-6.01); receptive syringe sharing (aOR 3.13; 95% CI 1.73-5.66); and number of injections per day (aOR 1.08; 95% CI 1.01-1.15). Rural PWID who engage in transactional sex are characterized by multiple vulnerabilities that increase their HIV risk.

Prevalence and risk factors associated with HIV/hepatitis B and HIV/hepatitis C co-infections among people who inject drugs in Mozambique.

BACKGROUND: There is scare information about HIV co-infections with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) among People Who Inject Drugs (PWID) in Mozambique. This information is critical to ensure the treatment necessary to decrease the progression of liver disease and the transmission of both HIV and hepatitis. We assess the prevalence of HIV, HBV and HCV co-infections as well as associated risk factors among PWID. METHODS: The first Bio-Behavioral Surveillance Survey was conducted in 2013-2014 among persons who self-reported to have ever injected drugs. Using respondent-driven sampling, PWID aged 18 years and older were recruited in two cross-sectional samples in Maputo and Nampula/Nacala, two large urban centers of Mozambique. Rapid screening of HIV, HBV (HBsAg) and HCV was performed on site. Data from participants in both cities were pooled to conduct RDS-weighted bivariate analyses with HIV/HBV and HIV/HCV co-infections as separate outcomes. Unweighted bivariate and multivariate logistic regression analyses were conducted to assess correlates of co-infection. RESULTS: Among 492 eligible PWID, 93.3% were male and median age was 32 years [IQR: 27-36]. HIV, HBV and HCV prevalence were respectively 44.9% (95% CI:37.6-52.3), 32.8% (95% CI:26.3-39.5) and 38.3 (95% CI:30.6-45.9). Co-infections of HIV/HBV, HIV/HCV and HIV/HBV/HCV were identified in 13.1% (95% CI:7.2-18.9), 29.5% (95% CI:22.2-36.8) and 9.2% (95% CI:3.7-14.7) of PWID, respectively. Older age, history of needle/syringe sharing and history of injection with used needle/syringe was associated with HIV/HBV co-infection. Living in Maputo city, have older age, history of needle/syringe sharing and history of injection with used needle/syringe was associated with HIV/HCV co-infection. CONCLUSION: There is a high burden of HBV and HCV among HIV-infected PWID in Mozambique. Our results highlight the need for targeted harm reduction interventions that include needle exchange programs and integrated services for the diagnosis and treatment of HIV, HBV and HCV to address these epidemics among PWID. Efforts should be made to strengthen ART coverage in the population as an important treatment strategy for both viruses.

Personal historical perspective of HIV: part 11.

All animal life on earth is thought to have a common origin and have common genetic mechanisms. Evolution has enabled differentiation of species. Pathogens likewise have evolved within various species and mostly come to a settled dynamic equilibrium such that co-existence results (pathogens ideally should not kill their hosts). Problems arise when pathogens jump species because the new host had not developed any resistance. These infections from related species are known as zoonoses. COVID-19 is the latest example of a virus entering another species but HIV (and various strains of influenza) were previous examples. HIV entered the human population from monkeys in Africa. These two papers outline the underlying principle of HIV and the differing epidemiologies in Africa, the USA and in Edinburgh. The underlying immunosuppression of HIV in Africa was initially hidden behind common infections and HIV first came to world awareness in focal areas of the USA as a disease seemingly limited to gay males. The epidemic of intravenous drug abuse in Edinburgh was associated with overlapping epidemics of bloodborne viruses like hepatitis B, hepatitis C and HIV.

Exposure to HIV risks among young people who use drugs (YPUD) in three cities in Vietnam: time to develop targeted interventions.

INTRODUCTION: The aim of this study is to identify the profiles of young people who use drugs (YPUD) and their exposure to HIV risks in the 3 main cities of Vietnam, Haiphong, Hanoi, and Ho Chi Minh City (HCMC), in order to design a community-based intervention to prevent HIV. METHODS: A survey using respondent-driven sampling (RDS) was conducted among YPUD aged 16-24. Participants were eligible if they reported drug use, confirmed by a urine test. After obtaining informed consent, they were screened for HIV/HCV and assessed using face-to-face questionnaires and self-report. A cluster analysis was conducted, taking into account risk behaviors and confirmed HIV-positive status. RESULTS: Seven hundred and three YPUD aged 16-24 were recruited between October 2016 and February 2017, 584 of whom were included in the final analysis. Median age was 21 (17.7, 23.0); 79% were male, 18% female, and 2% transgender. Methamphetamines use was reported by 77%, followed by cannabis (51%) and heroin (17%); polydrug use was common; 15% had "ever" injected drugs. HIV prevalence was 7%. Among all participants, 48% reported non-consistent condom use and 1% reported needle/syringe sharing during the previous month. Four distinct profiles of HIV risk behaviors were identified: The high multiple-risk group mixed unsafe drug use with unsafe sexual practices and had higher prevalence of HIV; the second group practiced high-risk sex with non-consistent condom combined with methamphetamine use; the third group was a moderate-risk group with limited unsafe sexual practices; and the fourth was considered at "low-risk" as reportedly, most never had sex and never injected. The highest risk group included more female YPUD, living in HCMC, who used heroin and had unsafe sex with their regular partners. The second high-risk group included most of the MSM and all transgender people and frequently reported mental health disorders. CONCLUSIONS: The profiles of YPUD who are at risk of HIV vary according to age, location, and population group. Injecting YPUD are the most exposed to risk and need immediate attention. Sexual exposure to HIV is very common. Mental health is a major concern. Interventions need to be integrated in a differentiated but holistic approach.

Distributive Syringe Sharing and Use of Syringe Services Programs (SSPs) Among Persons Who Inject Drugs.

Monitoring distributive syringe sharing (DSS) and syringe services program (SSP) use among persons who inject drugs (PWID) is important for HIV prevention. PWID aged ≥ 18 in 20 US cities were recruited for National HIV Behavioral Surveillance in 2015 using respondent-driven sampling, interviewed and offered HIV testing. Bivariate and multivariable analyses via log-linked Poisson regression with generalized estimating equations were conducted to examine associations between demographic and behavioral variables and DSS. Effect of SSP use on DSS by HIV sero-status was assessed by including an interaction between SSP and sero-status. Analyses were adjusted for sampling design. Among 10,402 PWID, 42% reported DSS. DSS was less likely to be reported among HIV-positive compared to HIV-negative PWID (aPR = 0.51, CI 0.45-0.60), and among those who primarily obtained syringes from SSPs versus those who did not (aPR = 0.82, 95% CI 0.77-0.88). After adjustment, those who primarily used SSPs were less likely to report DSS than those who did not among both HIV-negative PWID (aPR = 0.84, 95% CI 0.78-0.90) and HIV-positive PWID (aPR = 0.54, 95% CI 0.39-0.75). Findings support expansion of SSPs, and referrals to SSPs by providers working with PWID.

Characterizing Men Who Have Sex with Men and Use Injection Drugs in Vancouver, Canada.

We examined factors associated with reporting sex with men among men who inject drugs in Vancouver, Canada. Data were drawn from three open prospective cohorts of people who use drugs between 2005 and 2014. Generalized estimating equations were used to identify factors associated with reporting non-transactional sex with men (MSM) in the previous 6 months. Of 1663 men who used injection drugs, 225 (13.5%) were MSM over the study period. Sex with men was independently associated with younger age [Adjusted Odds Ratio (AOR) = 0.96], childhood sexual abuse (AOR = 2.65), sex work (AOR = 3.33), crystal methamphetamine use (AOR = 1.30), borrowing used syringes (AOR = 1.39), inconsistent condom use (AOR = 1.76), and HIV seropositivity (AOR = 3.82). MSM were less likely to be Hepatitis C-positive (AOR = 0.43) and to have accessed addiction treatment in the previous 6 months (AOR = 0.83) (all p < 0.05). Findings highlight vulnerabilities and resiliencies among MSM-PWID and indicate a need for trauma-informed and affirming harm reduction and substance use treatment services for MSM-PWID.

A New Generation of Drug Users in St. Petersburg, Russia? HIV, HCV, and Overdose Risks in a Mixed-Methods Pilot Study of Young Hard Drug Users.

Russia has a widespread injection drug use epidemic with high prevalence of HIV and HCV among people who inject drugs (PWID). We conducted a mixed methods study of young (age 18-26) hard drug users in St. Petersburg. Thirty-nine structured and 10 semi-structured interviews were conducted. No HIV cases and two HCV cases were detected among the PWID subsample (n = 29). Amphetamine and other stimulants were common (70%), opioid use was rare and episodic. Consistent condom use was 10%. No PWID reported syringe-sharing, 51% reported other drug paraphernalia sharing. Most (89%) never or rarely communicated with older (30 +) opiate users. A new cohort of drug users in St. Petersburg may have emerged, which is much safer in its injection practices compared to previous cohorts. However, risky sexual practices among this new cohort may expose them to the possibility of sexual transmission of HIV and widespread drug paraphernalia sharing to the HCV epidemic.

Injection and Heterosexual Risk Behaviors for HIV Infection Among Non-gay Identifying Men Who Have Sex with Men and Women.

Non-gay identifying men who have sex with men and women (MSMW) are an important subgroup of men who have sex with men (MSM) and have been underrepresented in studies of MSM that only use gay venues to draw their samples. We assessed heterosexual and drug use risks of MSMW who use drugs in a sample of male entrants to the Mount Sinai Beth Israel drug treatment programs from 2005 to 2018. Blood samples were collected and tested for HIV and HSV-2 infections. Among HIV seronegative participants, MSMW had significantly greater odds of sharing used needles with others, and reporting unprotected sex with female casual partners and female commercial sex partners, compared to their counterparts who reported sex with women exclusively (MSWE). Although not recruited from gay venues, MSMW had a significantly higher HIV prevalence than MSWE (23% vs. 10%, p < 0.001). Interventions that are specifically tailored to HIV prevention among MSMW are needed to ameliorate the prevalence of HIV risks and infection.

Street-involved youth engaged in sex work at increased risk of syringe sharing.

Syringe sharing places street-involved young people at risk of acquiring HIV and hepatitis C. While markers of economic marginalization, such as homelessness, have been linked with syringe sharing and have led to targeted interventions, the relationship between syringe sharing and other markers of economic vulnerability, such as sex work, are not well documented among young people. This study examines whether those engaged in sex work are at increased risk of syringe borrowing and syringe lending among street-involved youth who use injection drugs in Vancouver, Canada. Between September 2005 and May 2014, data was collected from the At-Risk Youth Study (ARYS), a prospective cohort of street involved youth aged 14-26. Generalized estimating equations with a confounding model building approach was used to examine the relationship between sex work and syringe borrowing and lending. 498 youth reported injecting drugs at some point during the study period and were therefore included in the analysis. In multivariable analysis, youth who engaged in sex work were at an elevated risk of both syringe borrowing (Adjusted Odds Ratio (AOR) = 2.17, 95% Confidence Interval [CI] = 1.40-3.36) and syringe lending (AOR = 1.66, 95% CI = 1.07-2.59). Our study found that youth engaged in street-based sex work were at a significantly higher risk of both syringe borrowing and lending among youth who use injection drugs in Vancouver. Ready access to clean syringes, safer working conditions for sex workers to enable risk reduction measures, and increased access to addiction treatment are identified as promising opportunities for reducing syringe sharing in this setting.

Are there missed opportunities for vaccinating against hepatitis B among people who inject drugs in the UK?

Sustaining the impact of hepatitis B virus (HBV) vaccination on incidence and prevalence of HBV infection requires increasing and maintaining the uptake of vaccine among those at risk. In recent years, the level of vaccine uptake among people who inject drugs (PWID) in the UK has levelled-off. Data (2015-2016) from the national unlinked-anonymous monitoring survey of PWID, an annual survey that collects data from PWID across England, Wales and Northern Ireland, were used to examine HBV vaccine uptake. Data from participants who had injected drugs during the previous year were used to investigate sources of hepatitis B vaccine doses as well as factors associated with vaccine uptake. Among the 3175 anti-HBc-negative participants, 3138 (99%) reported their vaccination status; 23% (714) reported no vaccine uptake. Among those not vaccinated, 447 (63%) reported being sexually active and 116 (16%) reported sharing needles and syringes. Majority of those not vaccinated reported accessing services in the previous year that could have provided hepatitis B vaccine doses. These missed opportunities for vaccinating of PWID indicate a need for additional targeted interventions.

Understanding hepatitis B, hepatitis C and HIV among people who inject drugs in South Africa: findings from a three-city cross-sectional survey.

BACKGROUND: People who inject drugs (PWID) are at high risk for hepatitis C (HCV), hepatitis B (HBV) and HIV without accessible harm reduction programmes. Coverage of needle and syringe and opioid substitution therapy (OST) services in South Africa is below global recommendations and no hepatitis services exist for PWID. We assessed HCV, HBV and HIV prevalence and risk factors among PWID accessing harm reduction services in Cape Town, Durban and Pretoria to inform policy and programming. METHODS: We conducted a cross-sectional survey among PWID in these cities between August 2016 and October 2017. Participants were opportunistically sampled while accessing services. Study team members administered a questionnaire that assessed sociodemographic characteristics, drug use and sexual risk practices. We tested for HCV (antibody, viral load and genotype), HBV surface antigen (HBsAg) and HIV. Bivariate and multivariate analyses assessed associations with HCV serostatus. RESULTS: Nine hundred and forty-three PWID were included in the per protocol analysis. The majority (87%, 819/943) were male, the overall median age was 29 and most lived on the street (66%, 626/943). At last injection, 77% (722/943) reported using a new needle and syringe and 17% (163/943) shared equipment. HIV prevalence was 21% (196/926), HBsAg positivity 5% (47/936), HCV seroprevalence 55% (513/937), HCV viraemic prevalence (proportion tested with detectable HCV) 43% (404/937) and HCV viraemic rate (proportion HCV antibody positive with detectable HCV) 79% (404/513). HCV genotype 1a (73%, 270/368) was the most prevalent. In multivariate analysis, HCV infection was positively associated with residing in Pretoria (adjusted odds ratio (aOR) 1.27, 95% CI 1.21-1.34), living on the street (aOR 1.90, 95% CI 1.38-2.60), frequent injecting (aOR 1.58, 95% CI 1.15-2.16) and HIV infection (aOR 1.69, 95% CI 1.15-2.47), and negatively associated with black race (aOR 0.52, 95% CI 0.36-0.74) and sexual activity in the previous month (aOR 0.61, 95% CI 0.42-0.88). CONCLUSIONS: HCV and HIV are major health threats affecting PWID in these cities. Access to OST and needle and syringe services needs to be increased and integrated with HCV services. Social and structural factors affecting PWID who live on the street need to be addressed.

Comparing Injecting Risk Behaviors of Long-Term Injectors with New Injectors in Tehran, Iran.

BACKGROUND: Global estimates suggest there are 15.6 million people who inject drugs (PWID) of whom 17.8% are living with HIV.Few studies have characterized newly-onset injectors with long-term injectors and its association with injecting risk behaviors. OBJECTIVES: We examined the relationship between length of injection and risk behaviors among people who inject drugs (PWID) in Tehran, Iran. METHODS: A cross-sectional study was conducted among PWID, from March to August 2016 in Tehran, Iran. PWID were recruited by convenience and snowball sampling from five Drop-in Centers (DIC) located in the south of Tehran. Our primary independent variable was length of injecting career, defined as the number of months since injecting initiation. Those defined as new injectors (were injecting for less than 18 months), and long-term injectors (as injecting drugs for more than 18 months). We reported the adjusted odds ratio (aOR) point estimate and 95% confidence interval (CI95%) as the effect measure. The level of significance used in multiple logistic regression model was 0.05. We used STATA v. 11 for all analyzes. RESULTS: The analytical sample comprised of 500 participants (100% male). Mean (±SD) age of PWID with a length of injection history was 31.2 ± 7.2 years. Overall, 270 (54%) (CI95%: 49.6%, 58.4%) of participants were long-term injectors. The average age of drug use initiation among long-term injectors group was lower as compared to new injectors group (31.2 vs. 29.4, p < 0.001). The odds of distributive syringe sharing among new injectors were two times higher than long-term injectors (AOR = 2.1, 95% CI 1.4-4.7). The odds of receptive syringe sharing were lower among new injectors group (AOR = 0.7, CI95% 0.2-0.87), compared to long-term injectors. New injectors had higher odds of reusing their own syringes (OR = 2.8, 95% CI: 1.4-5.7; p = 0.01). CONCLUSIONS: Improvements in harm reduction service provision can occur through taregted risk reduction education for new injectors focusing on reducing distributive syringe sharing among them.

Syringe Sharing in Drug Injecting Dyads: A Cross-Classified Multilevel Analysis of Social Networks.

We examined the association of dyadic-level factors with syringe sharing among people who inject drugs (PWID) in Kerman, Iran. In a cross-sectional study, we collected data on 329 drug-injecting dyads by individual face-to-face interviews. An injecting dyad was defined as 2 PWID who knew each other and injected drugs together during the last 6 months. If they reported at least 1 occasion of syringe sharing, the dyad was considered high-risk. Dyadic-level factors associated with syringe sharing were assessed using cross-classified multilevel logistic regression. The rate of syringe sharing was significantly higher for dyads who were more intimate (adjusted odds ratio [AOR] 4.5, CI 95%, 2.3-8.6), who had instrumental support (AOR 2.1, 95% CI 1.1-4.5), and who pooled money for drugs (AOR 4.1, 95% CI 2.0-8.3). The rate was lower in same-sex dyads (AOR 0.4, 95% CI 0.2-0.9) and in dyads who shared health information (AOR 0.5, 95% CI 0.2-0.9). Findings highlight close-peer influences on syringe-sharing behavior.

Quantifying potentially infectious sharing patterns among people who inject drugs in Baltimore, USA.

Mixing matrices quantify how people with similar or different characteristics make contact with each other, creating potential for disease transmission. Little empirical data on mixing patterns among persons who inject drugs (PWID) are available to inform models of blood-borne disease such as HIV and hepatitis C virus. Egocentric drug network data provided by PWID in Baltimore, Maryland between 2005 and 2007 were used to characterise drug equipment-sharing patterns according to age, race and gender. Black PWID and PWID who were single (i.e. no stable sexual partner) self-reported larger equipment-sharing networks than their white and non-single counterparts. We also found evidence of assortative mixing according to age, gender and race, though to a slightly lesser degree in the case of gender. Highly assortative mixing according to race and gender highlights the existence of demographically isolated clusters, for whom generalised treatment interventions may have limited benefits unless targeted directly. These findings provide novel insights into mixing patterns of PWID for which little empirical data are available. The age-specific assortativity we observed is also significant in light of its role as a key driver of transmission for other pathogens such as influenza and tuberculosis.

Prevalence and correlates of HIV infection among men who inject drugs in a remote area of Vietnam.

BACKGROUND: Lack of information on the HIV epidemic among men who inject drugs (MWID) in northwestern Vietnam, a remote area, may hamper national efforts to control the disease. We examined HIV prevalence, needle-syringe sharing behaviors, and associated factors among MWID in three areas of northwestern Vietnam. METHODS: We used descriptive analysis to report the characteristics, frequency of risk behaviors, and of access to healthcare services among the MWID. Univariable logistic regression was used to assess the associations between the HIV infection, needle-syringe sharing behaviors, and their independent variables. We further explored these associations in multivariable analyses where we included independent variables based on a priori knowledge and their associations with the dependent variables determined in univariable analyses (p <  0.25). RESULTS: The HIV prevalence was 37.9, 16.9, and 18.5% for Tuan Giao, Bat Xat, and Lao Cai City, respectively, and 25.4% overall. MWID of Thai minority ethnicity were more likely to be HIV-positive (adjusted odds ratio (AOR) 3.55; 95% confidence interval (CI) 1.84-6.87). The rate of needle-syringe sharing in the previous 6 months was approximately 9% among the MWID in Tuan Giao and Lao Cai City, and 27.8% in Bat Xat. Two thirds of the participants never underwent HIV testing before this study. Ever having been tested for HIV before this study was not associated with any needle-syringe sharing behaviors. Among the HIV-positive MWID, those who received free clean needles and syringes were less likely to give used needles and syringes to peers (AOR 0.21; 95% CI 0.06-0.79). Going to a "hotspot" in the previous week was associated with increased odds of needle-syringe sharing in multiple subgroups. CONCLUSION: Our findings on HIV prevalence and testing participation among a subset of MWID in the northwestern Vietnam were corroborated with trend analysis results from the most recent HIV/STI Integrated Biological and Behavioral Surveillance report (data last collected in 2013.) We provided important insights into these MWID's risky injection behaviors. We suggest heightened emphasis on HIV testing and needle and syringe provision for this population. Also, policymakers and program implementers should target hotspots as a main venue to tackle HIV epidemics.

Comparing risk environments for HIV among people who inject drugs from three cities in Northern Mexico.

BACKGROUND: A large body of research has investigated the rise of injection drug use and HIV transmission in Tijuana and Ciudad Juarez (CJ). However, little is known about the dynamics of injecting in Hermosillo. This study compares drug-related behaviors and risk environment for HIV of people who inject drugs (PWID) across Tijuana, CJ, and Hermosillo to identify factors that could explain differences in HIV prevalence. METHODS: Data from Tijuana belong to a prospective study (El Cuete IV). Data from Hermosillo and Ciudad Juarez belong to a cross-sectional study. Both studies collected data in places where PWID spend time. All participants completed quantitative behavioral and serological testing for HIV. Datasets were merged using only comparable variables. Descriptive statistics tests were used to compare sociodemographic and behavioral characteristics of people who inject drugs PWID sampled in each city. A logistic regression model was built to identify factors independently associated with the likelihood of reporting receptive syringe sharing in the past 6 months. RESULTS: A total of 1494 PWID provided data between March 2011 and May 2012. HIV prevalence differed significantly between participants in Tijuana (4.2%), CJ (7.7%), and Hermosillo (5.2%; p < 0.05). PWID from Hermosillo reported better living conditions, less frequency of drug injection, and lower prevalence of syringe sharing (p < 0.01). PWID from CJ reported a higher prevalence of syringe sharing and confiscation by police (p < 0.01). In a multivariable logistic regression model, living in Hermosillo compared to Tijuana (adjusted odds ratio [AOR] = 0.42, 95% confidence interval [CI] 0.29-0.61) and being female (AOR = 0.61, 95% CI 0.45-0.83) were protective against syringe sharing. Having used crystal meth (AOR = 1.62, 95% CI 1.24-2.13, p = 0.001), having experienced syringe confiscation by police in the last 6 months (AOR = 1.78, 95% CI 1.34-2.40), and lower perception of syringe availability (AOR = 2.15, 95% CI 1.59-2.91) were significantly associated with syringe sharing (p < 0.05). CONCLUSIONS: Differences in HIV prevalence across cities reflect mainly differences in risk environments experienced by PWID, shaped by police practices, access to injection equipment, and dynamics of drug markets. Findings highlight the importance of ensuring sterile syringe availability through harm reduction services and a human rights approach to drug harms in northern Mexico and to generate better understanding of local dynamics and contexts of drug use for designing proper harm reduction programs.