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INTRODUCTION: HPTN 083 demonstrated the superiority of long-acting cabotegravir (CAB-LA) versus daily oral emtricitabine/tenofovir disoproxil fumarate (TDF/FTC) as pre-exposure prophylaxis (PrEP) among cisgender men and transgender women who have sex with men (MSM/TGW). HPTN 083 provided the first opportunity to understand experiences with injectable PrEP in a clinical trial. METHODS: Participants from two US sites (Chicago, IL and Atlanta, GA) and one international site (Rio de Janeiro, Brazil) were purposively sampled for individual qualitative interviews (N = 40), between November 2019 and March 2020, to explore trial experiences, barriers to adherence and other factors that may have impacted study implementation or outcomes. The blinded phase ended early due to efficacy; this analysis includes interviews conducted prior to unblinding with three groups defined by adherence (i.e. injection visit attendance): adherent (n = 27), non-adherent (n = 12) and early discontinuers (n = 1). Data were organized using NVivo software and analysed using content analysis. RESULTS: Participants (mean age: 27) were primarily cisgender MSM (90%) and Black/African American (60%). Reasons for trial enrolment and PrEP use included a preference for using HIV prevention medication versus treatment in the event of HIV acquisition; the ability to enhance health via study-related education and services; access to a novel, convenient HIV prevention product at no cost; and contributing to MSM/TGW communities through research. Participants contrasted positive experiences with study staff with their routine clinical care, and emphasized increased scheduling flexibility, thorough communication, non-judgemental counselling and open, affirming environments (e.g. compassion, less stigma) as adherence facilitators. Injection experiences were positive overall; some described early injection-related anxiety, which abated with time and when given some measure of control (e.g. pre-injection countdown), and minimal injection site discomfort. Some concerns and misperceptions about injectable PrEP were reported. Barriers to adherence, across all adherence categories, included structural factors (e.g. financial constraints, travel) and competing demands (e.g. work schedules). CONCLUSIONS: Respondents viewed injectable PrEP trial participation as a positive experience and a means of enhancing wellbeing. Study site flexibility and affirming clinic environments, inclusive of non-judgemental counselling, were key facilitators of adherence. To support injection persistence, interventions that address structural barriers and promote flexible means of injection delivery may be most effective.

: Introduction: HPTN 083 demonstrated the superiority of long‐acting cabotegravir (CAB‐LA) versus daily oral emtricitabine/tenofovir disoproxil fumarate (TDF/FTC) as pre‐exposure prophylaxis (PrEP) among cisgender men and transgender women who have sex with men (MSM/TGW). HPTN 083 provided the first opportunity to understand experiences with injectable PrEP in a clinical trial. Methods: Participants from two US sites (Chicago, IL and Atlanta, GA) and one international site (Rio de Janeiro, Brazil) were purposively sampled for individual qualitative interviews (N = 40), between November 2019 and March 2020, to explore trial experiences, barriers to adherence and other factors that may have impacted study implementation or outcomes. The blinded phase ended early due to efficacy; this analysis includes interviews conducted prior to unblinding with three groups defined by adherence (i.e. injection visit attendance): adherent (n = 27), non‐adherent (n = 12) and early discontinuers (n = 1). Data were organized using NVivo software and analysed using content analysis. Results: Participants (mean age: 27) were primarily cisgender MSM (90%) and Black/African American (60%). Reasons for trial enrolment and PrEP use included a preference for using HIV prevention medication versus treatment in the event of HIV acquisition; the ability to enhance health via study‐related education and services; access to a novel, convenient HIV prevention product at no cost; and contributing to MSM/TGW communities through research. Participants contrasted positive experiences with study staff with their routine clinical care, and emphasized increased scheduling flexibility, thorough communication, non‐judgemental counselling and open, affirming environments (e.g. compassion, less stigma) as adherence facilitators. Injection experiences were positive overall; some described early injection‐related anxiety, which abated with time and when given some measure of control (e.g. pre‐injection countdown), and minimal injection site discomfort. Some concerns and misperceptions about injectable PrEP were reported. Barriers to adherence, across all adherence categories, included structural factors (e.g. financial constraints, travel) and competing demands (e.g. work schedules). Conclusions: Respondents viewed injectable PrEP trial participation as a positive experience and a means of enhancing wellbeing. Study site flexibility and affirming clinic environments, inclusive of non‐judgemental counselling, were key facilitators of adherence. To support injection persistence, interventions that address structural barriers and promote flexible means of injection delivery may be most effective., INTRODUCTION HIV Prevention Trials Network (HPTN) 083 was the first large‐scale, randomized, double‐blind efficacy trial of long‐acting injectable cabotegravir (CAB‐LA) versus daily oral emtricitabine/tenofovir disoproxil fumarate (TDF/FTC) as pre‐exposure prophylaxis [...]

OBJECTIVE: MSM in India are at a high risk for HIV infection given psychosocial challenges, sexual orientation stress, and stigma. We examined the cost-effectiveness of a novel resilience-based psychosocial intervention for MSM in India. DESIGN: We parameterized a validated microsimulation model (CEPAC) with India-specific data and results from a randomized trial and examined two strategies for MSM: status quo HIV care ( SQ ), and a trial-based psychosocial intervention ( INT ) focused on building resilience to stress, improving mental health, and reducing condomless anal sex (CAS). METHODS: We projected lifetime clinical and economic outcomes for MSM without HIV initially. Intervention effectiveness, defined as reduction in self-reported CAS, was estimated at 38%; cost was $49.37/participant. We used a willingness-to-pay threshold of US$2100 (2019 Indian per capita GDP) per year of life saved (YLS) to define cost-effectiveness. We also assessed the 5-year budget impact of offering this intervention to 20% of Indian MSM. RESULTS: Model projections showed the intervention would avert 2940 HIV infections among MSM over 10 years. Over a lifetime horizon, the intervention was cost-effective (ICER = $900/YLS). Results were most sensitive to intervention effectiveness and cost; the intervention remained cost-effective under plausible ranges of these parameters. Offering this intervention in the public sector would require an additional US$28 M over 5 years compared with SQ . CONCLUSION: A resilience-based psychosocial intervention integrated with HIV risk reduction counseling among MSM in India would reduce HIV infections and be cost-effective. Programs using this approach should be expanded as a part of comprehensive HIV prevention in India.

Substance use in the U.S. varies by geographic region. Opioid prescribing practices and marijuana, heroin, and methamphetamine availability are evolving differently across regions. We examined self-reported substance use among people living with HIV (PLWH) in care at seven sites from 2017-2019 to understand current regional substance use patterns. We calculated the percentage and standardized percentage of PLWH reporting current drug use and at-risk and binge alcohol use by U.S. Census Bureau geographic region and examined associations in adjusted logistic regression analyses. Among 7,686 PLWH, marijuana use was the most prevalent drug (30%), followed by methamphetamine/crystal (8%), cocaine/crack (7%), and illicit opioids (3%). One-third reported binge alcohol use (32%). Differences in percent of current use by region were seen for marijuana (24-41%) and methamphetamine/crystal (2-15%), with more use in the West and Northeast, and binge alcohol use (26-40%). In adjusted analyses, PLWH in the Midwest were significantly less likely to use methamphetamine/crystal (aOR: 0.13;0.06-0.25) or illicit opioids (aOR:0.16;0.05-0.53), and PLWH in the Northeast were more likely to use cocaine/crack (aOR:1.59;1.16-2.17), compared to PLWH in the West. Understanding differences in substance use patterns in the current era, as policies continue to evolve, will enable more targeted interventions in clinical settings among PLWH.

Engagement with HIV-prevention services varies among sexual minority men (SMM). 183 HIV-negative SMM completed a baseline assessment including sociodemographic, psychosocial, identity and stigma, and sexuality measures, as well as HIV-prevention behaviors: (1) date of most recent HIV test, (2) whether they discussed HIV or (3) sexual behavior with their provider, and (4) disclosure to provider about engaging in condomless anal sex (CAS). Factor analysis of these four items yielded an HIV-prevention engagement factor score. Stochastic search variable selection (SSVS) followed by multiple linear regression identified variables associated with HIV-prevention engagement. SSVS identified three variables for inclusion in a multiple linear regression model. Not disclosing sexual orientation to one's provider (p

BackgroundSafe and effective long-acting injectable agents for preexposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) infection are needed to increase the options for preventing HIV infection.MethodsWe conducted a randomized, double-blind, double-dummy, noninferiority trial to compare long-acting injectable cabotegravir (CAB-LA, an integrase strand-transfer inhibitor [INSTI]) at a dose of 600 mg, given intramuscularly every 8 weeks, with daily oral tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) for the prevention of HIV infection in at-risk cisgender men who have sex with men (MSM) and in at-risk transgender women who have sex with men. Participants were randomly assigned (1:1) to receive one of the two regimens and were followed for 153 weeks. HIV testing and safety evaluations were performed. The primary end point was incident HIV infection.ResultsThe intention-to-treat population included 4566 participants who underwent randomization; 570 (12.5%) identified as transgender women, and the median age was 26 years (interquartile range, 22 to 32). The trial was stopped early for efficacy on review of the results of the first preplanned interim end-point analysis. Among 1698 participants from the United States, 845 (49.8%) identified as Black. Incident HIV infection occurred in 52 participants: 13 in the cabotegravir group (incidence, 0.41 per 100 person-years) and 39 in the TDF-FTC group (incidence, 1.22 per 100 person-years) (hazard ratio, 0.34; 95% confidence interval, 0.18 to 0.62). The effect was consistent across prespecified subgroups. Injection-site reactions were reported in 81.4% of the participants in the cabotegravir group and in 31.3% of those in the TDF-FTC group. In the participants in whom HIV infection was diagnosed after exposure to CAB-LA, INSTI resistance and delays in the detection of HIV infection were noted. No safety concerns were identified.ConclusionsCAB-LA was superior to daily oral TDF-FTC in preventing HIV infection among MSM and transgender women. Strategies are needed to prevent INSTI resistance in cases of CAB-LA PrEP failure. (Funded by the National Institute of Allergy and Infectious Diseases and others; HPTN 083 ClinicalTrials.gov number, NCT02720094.).

IntroductionCOVID-19 parallels HIV in many ways. Socio-behavioural science has been critical in elucidating the context and factors surrounding individual levels of engagement with known effective prevention and treatment tools for HIV, thus offering important lessons for ongoing efforts to combat the COVID-19 pandemic.DiscussionNon-adherence to effective disease mitigation strategies (e.g. condoms for HIV and masks for COVID-19) can be attributed in part to prioritizing comfort, convenience and individual autonomy over public health. Importantly, misinformation can fuel denialism and conspiracies that discredit scientific knowledge and motivate nonadherence. These preferences and the extent to which individuals can act on their preferences may be constrained by the structures and culture in which they live. Both HIV and COVID-19 have been politicized and influenced by evolving recommendations from scientists, clinicians, policymakers and politically motivated organizations. While vaccines are vital for ending both pandemics, their impact will depend on availability and uptake. Four decades of experience with the HIV epidemic have shown that information alone is insufficient to overcome these challenges; interventions must address the underlying, often complex factors that influence human behaviour. This article builds from socio-behavioural science theory and describes practical and successful approaches to enable and support adherence to prevention and treatment strategies, including vaccine adoption. Key methods include reframing tools to enhance motivation, promoting centralized sources of trusted information, strategic development and messaging with and within key populations (e.g. through social media) and appealing to self-empowerment, altruism and informed decision making. Orchestrated evidence-based activism is needed to overcome manipulative politicization, while consistent transparent messaging around scientific discoveries and clinical recommendations are critical for public acceptance and support. Ultimately, the effectiveness of COVID-19 vaccines will depend on our ability to engender trust in the communities most affected.ConclusionsMany lessons learned from socio-behavioural science in the HIV pandemic are applicable to the COVID-19 pandemic. Individual behaviour must be understood within its interpersonal and societal context to address the current barriers to adherence to disease-mitigating strategies and promote an effective response to the COVID-19 pandemic, which is likely to be endured for the foreseeable future.

Psychosocial syndemic conditions have received more attention regarding their deleterious effects on HIV acquisition risk than for their potential impact on HIV treatment and viral suppression. To examine syndemic conditions' impact on the HIV care continuum, we analyzed data collected from people living with HIV (N = 14,261) receiving care through The Centers for AIDS Research Network of Integrated Clinical Systems at seven sites from 2007 to 2017 who provided patient-reported outcomes ∼4-6 months apart. Syndemic condition count (depression, anxiety, substance use, and hazardous drinking), sexual risk group, and time in care were modeled to predict antiretroviral therapy (ART) adherence and viral suppression (HIV RNA

BackgroundMen who have sex with men (MSM) in India are extremely marginalised and stigmatised, and therefore experience immense psychosocial stress. As current HIV prevention interventions in India do not address mental health or resilience to these stressors, we aimed to evaluate a resilience-based psychosocial intervention in the context of HIV and sexually transmitted infection (STI) prevention.MethodsWe did a multicity, randomised, clinical efficacy trial in Chennai (governmental tuberculosis research institute) and Mumbai (non-governmental organisation for MSM), India. Inclusion criteria were MSM, aged 18 years or older, who were at risk of HIV acquisition or transmission, defined as having any of the following in the 4 months before screening: anal sex with four or more male partners (protected or unprotected), diagnosis of an STI, history of transactional sex activity, or condomless anal sex with a man who was of unknown HIV status or serodiscordant. Participants were required to speak English, Tamil (in Chennai), or Hindi (in Mumbai) fluently. Eligible individuals were randomly assigned (1:1) to either a resilience-based psychosocial HIV prevention intervention, consisting of group (four sessions) and individual (six sessions) counselling alongside HIV and STI voluntary counselling and testing, or a standard-of-care control comprising voluntary counselling and testing alone. The primary outcomes were number of condomless anal sex acts with male partners during the past month (at baseline and 4 months, 8 months, and 12 months after randomisation), and incident bacterial STIs (at 12 months after randomisation). Resilience-related mediators included self-esteem, self-acceptance, and depression. Recruitment is now closed. This trial is registered with ClinicalTrials.gov, NCT02556294.FindingsBetween Sept 4, 2015, and June 28, 2018, we enrolled 608 participants; 305 (50%) were assigned to the psychosocial intervention condition and 303 (50%) were assigned to the control condition. 510 (84%) of 608 men completed an assessment at 4 months after randomisation, 483 (79%) at 8 months, and 515 (85%) at 12 months. 512 (99%) of 515 men had STI data from the 12-month assessment. The intervention condition had a 56% larger reduction in condomless anal sex acts (95% CI 35-71; p

IntroductionLittle is known about onward HIV transmissions from people living with HIV (PLWH) in care. Antiretroviral therapy (ART) has increased in potency, and treatment as prevention (TasP) is an important component of ending the epidemic. Syndemic theory has informed modelling of HIV risk but has yet to inform modelling of HIV transmissions.MethodsData were from 61,198 primary HIV care visits for 14,261 PLWH receiving care through the Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems (CNICS) at seven United States (U.S.) sites from 2007 to 2017. Patient-reported outcomes and measures (PROs) of syndemic conditions - depressive symptoms, anxiety symptoms, drug use (opiates, amphetamines, crack/cocaine) and alcohol use - were collected approximately four to six months apart along with sexual behaviours (mean = 4.3 observations). Counts of syndemic conditions, HIV sexual risk group and time in care were modelled to predict estimated HIV transmissions resulting from sexual behaviour and viral suppression status (HIV RNA

Men who have sex with men (MSM) in the USA were the first population to be identified with AIDS and continue to be at very high risk of HIV acquisition. We did a systematic literature search to identify the factors that explain the reasons for the ongoing epidemic in this population, using a social-ecological perspective. Common features of the HIV epidemic in American MSM include role versatility and biological, individual, and social and structural factors. The high-prevalence networks of some racial and ethnic minority men are further concentrated because of assortative mixing, adverse life experiences (including high rates of incarceration), and avoidant behaviour because of negative interactions with the health-care system. Young MSM have additional risks for HIV because their impulse control is less developed and they are less familiar with serostatus and other risk mitigation discussions. They might benefit from prevention efforts that use digital technologies, which they often use to meet partners and obtain health-related information. Older MSM remain at risk of HIV and are the largest population of US residents with chronic HIV, requiring culturally responsive programmes that address longer-term comorbidities. Transgender MSM are an understudied population, but emerging data suggest that some are at great risk of HIV and require specifically tailored information on HIV prevention. In the current era of pre-exposure prophylaxis and the undetectable equals untransmittable campaign, training of health-care providers to create culturally competent programmes for all MSM is crucial, since the use of antiretrovirals is foundational to optimising HIV care and prevention. Effective control of the HIV epidemic among all American MSM will require scaling up programmes that address their common vulnerabilities, but are sufficiently nuanced to address the specific sociocultural, structural, and behavioural issues of diverse subgroups.

BackgroundMale sex workers (MSW) are disproportionately affected by HIV/AIDS, with an estimated HIV prevalence in the United States of 19.3%. Existing research suggests that MSW are also at risk of adverse psychosocial problems. Cross-sectional studies of MSW have suggested that co-occurring epidemics or a "syndemic" of psychosocial problems may increase vulnerability to HIV acquisition/transmission by elevated sexual risk. To the best of our knowledge, there are no published studies examining this relationship longitudinally among MSW. This study examined how a syndemic of 6 psychosocial problems result in additive risk for condomless anal sex (CAS) with male clients among a multicity, longitudinal cohort of MSW.SettingCommunity-based organization and health center in 2 Northeastern US cities.MethodsBetween 2015 and 2017, 100 MSW from Boston, MA and Providence, RI completed behavioral/psychosocial surveys at baseline, 6 months, and 12months. Generalized estimating equation modeling was used to examine the prospective relationship of additive psychosocial problems and subsequent CAS with male clients, adjusting for age, site, race/ethnicity, MSW-type, and HIV serostatus.ResultsMean age = 34.7 (SD = 11.8); 62% racial/ethnic minority; and 20% HIV+. The prevalence of 6 psychosocial syndemic problems was substantial at baseline and remained high at each time point (all within the past 6 months): 74% problematic depressive symptoms, 27% polydrug use (3+ drugs, not including stimulants), 57% stimulant (methamphetamine/cocaine/crack) use, 44% hazardous drinking, 15% experienced client-specific physical/sexual violence, and 57% childhood sexual abuse. Looking at the number of psychosocial problems experienced, 7% had zero, 27% had 1, 24% had 2, 27% had 3, and 15% had 4 or more. We identified a statistically significant positive "dose-response" relationship between the number of psychosocial problems and CAS with male clients over time, with the greatest odds of engaging in CAS with a male client over follow-up among those with 4 or more psychosocial problems (adjusted odds ratio = 5.18, 95% CI: 1.61 to 16.62).ConclusionsInternet escorts and street-based MSW are likely to experience psychosocial problems and engaging in HIV sexual risk with male clients. The accumulation of psychosocial problems additively predicted CAS with male clients in a prospective cohort of MSW. The specification of psychosocial problems presents distinct treatment targets for HIV prevention among MSW in the United States.

India has one of the largest numbers of men who have sex with men (MSM) globally; however, geographic data on sexually transmitted infection (STI) prevalence and associations with sexual behavior are limited. Six-hundred and eight MSM in Chennai and Mumbai underwent screening for a behavioral trial and were assessed for bacterial STIs (syphilis, chlamydia, gonorrhea), HIV, and past-month self-reported condomless anal sex (CAS). Mumbai (37.8%) had a greater prevalence of any STI than Chennai (27.6%) (prevalence ratio [PR] = 1.37, 95% CI: 1.09, 1.73). This pattern also emerged for gonorrhea and chlamydia separately but not syphilis. Conversely, Mumbai MSM reported lower rates of CAS (mean = 2.2) compared to Chennai MSM (mean = 14.0) (mean difference = -11.8, 95% CI: -14.6, -9.1). The interaction of city by CAS on any STI prevalence (PR = 2.09, 95% CI: 1.45, 3.01, p

Sexual minority men (SMM) face substantial disparities in rates of binge eating compared to heterosexual individuals, underscoring the need to study risk factors for the development of binge eating amongst SMM. One potential explanation for this disparity in binge eating is minority stress theory, which posits that minority groups face stressors, such as discrimination, due to their stigmatized position in society. Additionally, specific domains of discrimination may confer different levels of risk for binge eating. Therefore, the current study examined the association of various forms of discrimination, including appearance-based discrimination, and binge eating in a sample of SMM. A sample of 200 SMM (analytic sample of N = 187) from the greater Boston area completed self-report questionnaires assessing frequency of different forms of perceived discrimination (appearance, sexual orientation, race, etc.) and binge eating. A hierarchical binary logistic regression model was used to examine the association of different forms of discrimination with binge eating. 9% of the sample reported binge eating. Appearance-based discrimination was the most common form of discrimination (47%), and was significantly associated with binge eating, over and above all other forms of discrimination and sociodemographic variables, OR = 1.71, 95% CI = [1.24, 2.35], Wald χ2 (1) = 10.65, p = .001. Findings suggest that appearance-based discrimination may be related to binge eating in SMM. Clinicians may consider assessing appearance-based discrimination among SMM patients.

Background Stigma is associated with poor health among sexual minority individuals. However, no studies have examined the relationship between stigma and problematic drinking among male sex workers (MSWs). This study examined the relationship between sex work stigma and problematic alcohol use among MSWs.MethodsUsing baseline data from a cohort of 98 MSWs in the US Northeast enrolled between 2015 and 2016, we used logistic regression to examine associations between sex work stigma and hazardous drinking (Alcohol Use Disorders Identification Test (AUDIT) score ≥8) and sex work while drunk, and tested whether sexual orientation (gay vs non-gay identified) and social network size moderated these associations.ResultsAlmost half the sample (n = 46; 44%) reported hazardous drinking and 56 MSWs (57%) reported engaging in sex work while drunk. Sex work stigma was associated with hazardous drinking (adjusted odds ratio (aOR) 1.2, 95% confidence interval (CI) 1.05-1.36). Sexual orientation marginally moderated this relationship (P = 0.07), such that it was only significant among gay-identified MSWs (aOR 1.91, 95% CI 1.11-3.28), not among non-gay MSW. Similarly, sexual orientation moderated the effect of sex work stigma on sex work while drunk (P = 0.02), which was only significant among gay-identified MSWs (aOR 1.65, 95% CI 1.05-1.60). Social network size also moderated the effect of sex work stigma on sex work while drunk (P = 0.02), which was only significant among MSWs with small networks (aOR 1.26, 95% CI 1.00-1.58), suggesting large networks can be protective.ConclusionsGay MSWs may be particularly vulnerable to alcohol-related effects of stigma. Future interventions should consider engaging social networks to curb problematic drinking among MSWs.

BackgroundPre-exposure prophylaxis (PrEP) with emtricitabine/tenofovir disoproxil fumarate is efficacious in reducing HIV acquisition. For some gay, bisexual, and other men who have sex with men (MSM), daily ongoing PrEP may be unsuitable for use as a long-term prevention strategy because of episodic risk, cost issues, or concerns about the biological consequences of medication.SettingThis study evaluated the feasibility of short-term, fixed-interval episodic PrEP (Epi-PrEP) for use among vacationing MSM. We describe the feasibility of implementing a clinic-based Epi-PrEP pilot program for 48 MSM who reported occasional condomless sex and anticipated a defined high-risk time.MethodsThis was a nonrandomized naturalistic study of an observational clinical intervention. The primary outcome assessed was adherence, as measured by self-report and plasma tenofovir levels.ResultsOf 54 MSM who enrolled in the study, 48 completed the 3-month visit. The majority (93.7%) had tenofovir concentrations consistent with daily use on returning from vacation. Almost 3/4 reported condomless sex during vacation, and about 1/3 reported recreational drug use. During the 3-month follow-up, 1 participant had become HIV-infected because of a lapse in continued access to the PrEP after study. Although adverse events were common, none were serious. More than 70% of participants indicated an interest in daily ongoing PrEP use.ConclusionsEpi-PrEP was well tolerated by at risk MSM in this study, with high levels of medication adherence. Many participants felt the experience of initiating PrEP while on vacation could be a means for transition to long-term PrEP use.

BackgroundWhoonga is a smoked heroin-based street drug that first emerged in South Africa a decade ago. While previous scientific reports suggest that use is growing and youth are particularly vulnerable, trajectories of initiation are not well characterized.MethodsIn 2015, 30 men undergoing residential addiction treatment for this smoked heroin drug in KwaZulu-Natal, South Africa participated in semi-structured interviews about their experiences using the drug. Interview data were coded using qualitative content analysis.ResultsParticipant trajectories to initiating smoked heroin were "vertical" in the context of marijuana use or "horizontal" in the context of other hard drug use. Participants reporting vertical trajectories began smoking heroin as youth at school or in other settings where people were smoking marijuana. Several participants with horizontal trajectories started smoking heroin to address symptoms of other drug or alcohol addiction. Social influences on initiation emerged as an overarching theme. Members of participants' social networks who were smoking or distributing heroin figured prominently in initiation narratives. Surprisingly, references to injection drug use were absent from initiation narratives. Participants reported people who smoke heroin differ from those who inject heroin by race.ConclusionConsistent with theories implicating social and structural influences on substance use initiation, people who started smoking heroin had social contacts who smoked heroin and frequented places where substance use was common. Smoked heroin initiation for several participants with horizontal trajectories may have been averted if they accessed evidence-based treatments for stimulant or alcohol use disorders. With increasing reports of heroin use across Africa, a coordinated approach to address this growing epidemic is needed. However, because smoked heroin and injection heroin use occur in distinct risk environments, interventions tailored to people who use smoked heroin will be needed to prevent smoked heroin use, prevent transition to injection use, and mitigate other social harms.

Young Latino men who have sex with men (MSM) are a highly vulnerable population for HIV infection. Pre-exposure prophylaxis (PrEP) is a novel biomedical HIV prevention tool that may aid in reducing the disparity in HIV incidence among Latino MSM. However, PrEP use is disproportionally low among Latino MSM and, therefore, identifying barriers along the PrEP continuum of care (the "PrEP cascade") would provide insight into how to best deploy PrEP interventions. Syndemics theory is a prominent framework employed in HIV prevention; however, to date, no known studies have applied this theory to PrEP. Thus, the aim of the current study was to explore the association between syndemics and the PrEP cascade, including the degree to which psychosocial and structural syndemic constructs are related to the PrEP cascade. Participants were 151 young Latino MSM (M age = 24 years; SD = 3) residing in San Diego, California, who completed a battery of online self-report measures. Results indicated high levels of syndemic indicators and varying levels of engagement across the PrEP cascade. As syndemic indicators increased, the odds of engagement across the PrEP cascade were significantly lowered. Psychosocial and structural syndemic factors accounted for unique variance in the PrEP cascade. Results highlight the need for combination interventions that address both psychosocial and structural barriers to PrEP use and persistence among young Latino MSM.