The contribution of unstable housing to HIV and hepatitis C virus transmission among people who inject drugs globally, regionally, and at country level:a modelling study

BACKGROUND: A considerable proportion of people who inject drugs are unstably housed. Although unstable housing is associated with HIV and HCV infection among people who inject drugs, its contribution to transmission is unknown. We estimated the global and national proportions of incident HIV and HCV infections among people who inject drugs attributed to housing instability from 2020 to 2029. METHODS: In this modelling study, we developed country-level models of unstable housing and HIV and HCV transmission among people who inject drugs in 58 countries globally, calibrated to country-specific data on the prevalences of HIV and HCV and unstable housing. Based on a recently published systematic review, unstably housed people who inject drugs were assumed to have a 39% (95% CI 6–84) increased risk of HIV transmission and a 64% (95% CI 43–89%) increased risk of HCV transmission. We used pooled country-level estimates from systematic reviews on HCV and HIV prevalence in people who inject drugs. Our models estimated the transmission population attributable fraction (tPAF) of unstable housing to HIV and HCV transmission among people who inject drugs, defined as the percentage of infections prevented from 2020 to 2029 if the additional risk due to unstable housing was removed. FINDINGS: Our models were produced for 58 countries with sufficient data (accounting for >66% of the global people who inject drugs population). Globally, we project unstable housing contributes 7·9% (95% credibility interval [CrI] 2·3–15·7) of new HIV infections and 11·2% (7·7–15·5) of new HCV infections among people who inject drugs from 2020 to 2029. Country-level tPAFs were strongly associated with the prevalence of unstable housing. tPAFs were greater in high-income countries (HIV 17·2% [95% CrI 5·1–30·0]; HCV 19·4% [95% CrI 13·8–26·0]) than in low-income or middle-income countries (HIV 6·6% [95% CrI 1·8–13·1]; HCV 8·3% [95% CrI 5·5–11·7]). tPAFs for HIV and HCV were highest in Afghanistan, Czech Republic, India, USA, England, and Wales where unstable housing contributed more than 20% of new HIV and HCV infections. INTERPRETATION: Unstable housing is an important modifiable risk factor for HIV and HCV transmission among people who inject drugs in many countries. The study emphasises the importance of implementing initiatives to mitigate these risks and reduce housing instability. FUNDING: National Institute for Health Research and National Institute of Allergy and Infectious Diseases and National Institute for Drug Abuse

Visits to primary care physicians among persons who inject drugs at high risk of hepatitis C virus infection: room for improvement

The role of primary care physicians (PCP) in hepatitis C virus (HCV) prevention is increasingly emphasized. Yet, little is known about the patterns of contacts with PCP among persons who inject drugs (PWID). We sought to assess the 6-month prevalence of PCP visiting among PWID at risk of HCV infection and to explore the associated factors. Baseline data were collected from HCV-seronegative PWID recruited in HEPCO, an observational Hepatitis Cohort study (2004-2011) in Montreal, Canada. An interviewer-administered questionnaire elicited information on socio-demographic factors, drug use patterns and healthcare services utilization. Blood samples were tested for HCV antibodies. Using the Gelberg-Andersen Behavioral Model, hierarchical logistic regression analyses were conducted to identify predisposing, need and enabling factors associated with PCP visiting. Of the 349 participants (mean age = 34; 80.8% male), 32.1% reported visiting a PCP. In the multivariate model, among predisposing factors, male gender [adjusted odds ratio (AOR) = 0.45 (0.25-0.83)], chronic homelessness [AOR = 0.08 (0.01-0.67)], cocaine injection [AOR = 0.46 (0.28-0.76)] and reporting greater illegal or semi-legal income [AOR = 0.48 (0.27-0.85)] were negatively associated with PCP visits. Markers of need were not associated with the outcome. Among enabling factors, contact with street nurses [AOR = 3.86 (1.49-9.90)] and food banks [AOR = 2.01 (1.20-3.37)] was positively associated with PCP visiting. Only one third of participating PWID reported a recent visit to a PCP. While a host of predisposing factors seems to hamper timely contacts with PCP among high-risk PWID, community-based support services may play an important role in initiating dialogue with primary healthcare services in this population

Associations of substance use patterns with attempted suicide among persons who inject drugs: Can distinct use patterns play a role?

Background: While the elevated risk of suicide attempt among persons who inject drugs (PWID) is well documented, whether use of different substances is associated with varying degrees of risk remains unclear. We sought to examine the associations between substance use patterns and attempted suicide in a prospective cohort of PWID in Montreal, Canada. Methods: Between 2004 and 2011, participants completed an interviewer-administered questionnaire eliciting information on socio-demographic, substance use patterns, related behaviors, and mental health markers. Generalized estimating equations were used to model the relationship between self-reported use of six common substances (cocaine, amphetamine, opioids, sedative-hypnotics, cannabis and alcohol), associated patterns of use (chronic, occasional and none), and a recent (past six-month) suicide attempt. Results: At baseline, of 1,240 participants (median age: 39.1, 83.7% male), 71 (5.7%) reported a recent suicide attempt. Among 5,621 observations collected during follow-up, 221 attempts were reported by 143 (11.5%) participants. In multivariate analyses adjusting for socio-demographic and psychosocial stressors, among primary drugs of abuse, chronic [Adjusted Odds Ratio (AOR): 1.97] and occasional (AOR: 1.92) cocaine use, and chronic amphetamine use (AOR: 1.96) were independently associated with attempted suicide. Among co-used substances, chronic sedative-hypnotic use was independently associated with an attempt (AOR: 2.29). No statistically significant association was found for the remaining substances. Conclusion: Among PWID at high risk of attempted suicide, stimulant users appear to constitute a particularly vulnerable sub-group. While the mechanisms underlying these associations remain to be elucidated, findings suggest that stimulant-using PWID should constitute a prime focus of suicide prevention efforts

Portraying persons who inject drugs recently infected with hepatitis C accessing antiviral treatment : a cluster analysis

Objectives. To empirically determine a categorization of people who inject drug (PWIDs) recently infected with hepatitis C virus (HCV), in order to identify profiles most likely associated with early HCV treatment uptake. Methods.The study population was composed of HIV-negative PWIDs with a documented recent HCV infection. Eligibility criteria included being 18 years old or over, and having injected drugs in the previous 6 months preceding the estimated date of HCV exposure. Participant classification was carried out using a TwoStep cluster analysis. Results. FromSeptember 2007 to December 2011, 76 participants were included in the study. 60 participants were eligible for HCV treatment. Twenty-one participants initiated HCV treatment.The cluster analysis yielded 4 classes: class 1: Lukewarm health seekers dismissing HCV treatment offer; class 2: multisubstance users willing to shake off the hell; class 3: PWIDs unlinked to health service use; class 4: health seeker PWIDs willing to reverse the fate. Conclusion. Profiles generated by our analysis suggest that prior health care utilization, a key element for treatment uptake, differs between older and younger PWIDs. Such profiles could inform the development of targeted strategies to improve health outcomes and reduce HCV infection among PWIDs

Hepatitis C Virus seroconversion among persons who inject drugs in relation to primary care physician visiting: The potential role of primary healthcare in a combined approach to Hepatitis C prevention

Background: Meaningful reductions in Hepatitis C Virus (HCV) transmission rates among persons who inject drugs (PWID) require a comprehensive prevention approach, including access to harm reduction measures and to healthcare-related interventions, such as HCV screening, testing and antiviral treatment. Little is known, however, about the role of visiting a primary care physician (PCP) in relation to HCV infection risk among PWID, when integrated within a combined prevention approach. This study assessed the association between PCP visiting and HCV seroconversion among PWID attending needle exchange programs (NEP). Methods: A prospective cohort study, HEPCO, was conducted among active PWID in Montréal (2004-2013). Interviews scheduled at three- or six-month intervals included completion of an interviewer-administered questionnaire, and collection of blood samples for HCV antibody testing. HCV-seronegative participants who reported NEP attendance at baseline and had at least one follow-up visit were eligible for this study. HCV incidence was calculated using the person-time method. Time-varying Cox regression modeling was conducted to evaluate the relationship between self-reported recent PCP visiting and HCV incidence. Results: At baseline assessment, of 226 participants (80.5% male; median age: 30.6 years), 37.2% reported having recently visited a PCP. During 449.6 person-years of follow-up, 79 participants seroconverted to HCV [incidence rate: 17.6 per 100 person-years, 95% confidence interval (CI): 14.0-21.8]. Covariate-adjusted analyses indicated that visiting a PCP was associated with a lower risk of HCV infection [Adjusted Hazard Ratio: 0.54, 95% CI: 0.31-0.93]. Other independent predictors of HCV infection included unstable housing, cocaine injection and prescription opioid injection. Conclusion: Among PWID attending NEP, visiting a PCP was associated with a lower risk of HCV infection. Yet, only a minority of participants reported PCP visiting. Efforts to intensify engagement with PCP among PWID could potentially contribute to lower HCV transmission when integrated within a combined approach to prevention

Impact of HCV testing and treatment on HCV transmission among men who have sex with men and who inject drugs in San Francisco: A modelling analysis

BACKGROUND: Men who have sex with men who ever injected drugs (ever MSM-IDU) carry a high hepatitis C virus (HCV) burden. We estimated whether current HCV testing and treatment in San Francisco can achieve the 2030 World Health Organization (WHO) HCV elimination target on HCV incidence among ever MSM-IDU. METHODS: A dynamic HCV/HIV transmission model among MSM was calibrated to San Francisco data, including HCV antibody (15.5%, 2011) and HIV prevalence (32.8%, 2017) among ever MSM-IDU. MSM had high HCV testing (79%-86% ever tested, 2011-2019) and diagnosed MSM had high HCV treatment (65% ever treated, 2018). Following coronavirus disease 2019 (COVID-19)-related lockdowns, HCV testing and treatment decreased by 59%. RESULTS: Among all MSM, 43% of incident HCV infections in 2022 were IDU-related. Among ever MSM-IDU in 2015, HCV incidence was 1.2/100 person-years (95% credibility interval [CrI], 0.8-1.6). Assuming COVID-19-related declines in HCV testing/treatment persist until 2030, HCV incidence among ever MSM-IDU will decrease by 84.9% (95% CrI, 72.3%-90.8%) over 2015-2030. This decline is largely attributed to HCV testing and treatment (75.8%; 95% CrI, 66.7%-89.5%). Slightly greater decreases in HCV incidence (94%-95%) are projected if COVID-19 disruptions recover by 2025 or 2022. CONCLUSIONS: We estimate that HCV incidence will decline by >80% over 2015-2030 among ever MSM-IDU in San Francisco, achieving the WHO target

Preprint: Overdose prevention centres as spaces of safety, trust and inclusion: a causal pathway based on a realist review

Background: Overdose prevention centres (OPCs) are non-residential spaces where people can use illicit drugs (that they have obtained elsewhere) in the presence of staff who can intervene in order to prevent and reverse any overdoses that occur. Many reviews of OPCs exist, but few explain how OPCs work. Methods: We carried out a realist review, using the RAMESES reporting standards. We systematically searched for and then thematically analysed 391 documents that provide information on the contexts, mechanisms, and outcomes of OPCs. Findings: Our retroductive analysis identified a causal pathway that highlights the feeling of safety – and the immediate outcome of not dying - as conditions of possibility for the people who use OPCs to build trust and experience social inclusion. The combination of safety, trust, and social inclusion that is triggered by OPCs can – depending on the contexts in which they operate - generate other positive outcomes, which may include less risky drug use practices, reductions in blood borne viruses and injection-related infections and wounds, and access to housing. Interpretation: OPCs can enable people who live with structural violence and vulnerability to develop feelings of safety and trust that help them stay alive and to build longer term trajectories of social inclusion, with potential to improve other aspects of their health and living conditions

Overdose Prevention Centres, Safe Consumption Sites, and Drug Consumption Rooms: A Rapid Evidence Review

This rapid review on overdose prevention centres (OPCs) aims to collate and summarise existing evidence. It describes the impact of OPCs on individuals who use drugs, communities, and public health. This is to support decision making and understanding of service provision for health departments, potential providers, researchers, and elected officials (1). This document also covers some practical matters of running a service including day-to-day matters, costs, and any cost savings from their operation. We conclude with information on evaluation; services should be robustly evaluated

Overdose prevention centres, safe consumption sites, and drug consumption rooms: A rapid evidence review

This rapid review on overdose prevention centres (OPCs) aims to collate and summarise existing evidence. It describes the impact of OPCs on individuals who use drugs, communities, and public health