Risk behaviors and prevalence of hepatitis B and C among people who inject drugs in Georgia: integrated bio-behavioral survey (IBBS).

Injecting drug use is an important public health issue, causing significant morbidity and mortality worldwide. The contemporary drug market setting in Australia is defined by a lower prevalence and frequency of heroin injection among regular people who inject drugs (PWID) compared with in the past, and changing patterns of polydrug use, with some evidence of increasing use of pharmaceutical opioids. Our understanding of patterns of drug use and related risk behaviours among contemporary PWID is limited by the fact that much research has captured samples of predominantly older, long-term PWID, many of whom are on opioid substitution therapy (OST) and may use drugs only infrequently. The aim of the research presented in this thesis was to generate comprehensive information about patterns of drug use and associated risk behaviours among PWID who are active in contemporary settings, including understudied populations such as younger PWID, out-of-treatment PWID and PWID from culturally and linguistically diverse backgrounds. The Melbourne Injecting Drug User Cohort Study (MIX) is a prospective cohort of 688 community-recruited regular PWID. The median age of the cohort is 27.6 years and only 35% of participants were prescribed OST at baseline. Over 70% of the cohort completed a follow-up interview at 12 months post-baseline, demonstrating that it is possible to successfully retain a cohort of community-recruited PWID. Despite the uniqueness of this cohort, patterns of drug use by MIX participants were relatively similar to those displayed by sentinel samples of older, longer-term PWID. There were few differences in injecting initiation experiences between MIX participants who initiated injecting in contemporary settings and those who initiated in earlier settings and, although this had some ongoing impact, the relationship was not strongly related to current drug use patterns. Pharmaceutical opioid use was a key component of polydrug use among MIX participants, with 20% of the cohort reporting using illicitly-obtained pharmaceutical opioids in the month preceding baseline interview. Use of pharmaceutical opioids was however not sustained over time. The relationship between age and engagement in risk behaviours was examined using 10 years of data from the Australian Illicit Drug Reporting System, a national repeat cross-sectional survey of regular PWID recruited through needle and syringe programs, drug treatment and community settings. Older age was associated with decreased likelihood of engagement in a range of injecting-related and criminogenic risk behaviours. Injecting drug use among young people of African ethnicity was examined using MIX data and an additional qualitative study. Findings showed that injecting drug use (and substance use more broadly) and mental health are emerging issues among this community. Findings from this body of research inform the provision of harm reduction services which take into the account the key populations and patterns of drug use in the contemporary setting. Priority areas for future research include further research examining pharmaceutical opioid use among PWID, studies of substance use and mental health among resettled refugee youth, research into interventions to reduce injecting-related risk behaviours among younger PWID and additional longitudinal studies of PWID with a broader geographic focus.

BackgroundA Cross-sectional Rapid Situational Assessment of People Who Inject Drug (PWIDs) applying Respondent Driven sampling techniques (RDS) was used to recruit subjects/participants in a study aimed at assessing HIV prevalence and risk behaviors among injecting drug users in Nairobi and Coastal regions of Kenya. There is paucity of data and information on injecting drug use in sub-Saharan Africa and there is sufficient evidence of existence of the environment for development and growth of injecting drug use. Past studies on PWID and its association to HIV and AIDS that have been conducted in Kenya do not provide sufficient information to support effective planning and comprehensive national response to the HIV and AIDS epidemic.MethodsA cross-sectional study design was adopted in which a set of initial subjects referred to as ‘seeds’ were first identified from which an expanding chain of referrals were obtained, with subjects from each wave referring subjects of subsequent waves. The seeds were drawn randomly from the population and interviewed to pick the one with the largest network and other unique characteristics. A maximum of twelve seeds were recruited. The second stage involved conducting assessment visits to the sites to identify potential collaborators that included non-governmental organizations (NGOs), drug treatment centres, health facilities, community based organizations (CBO’s) among others. Three NGOs located in the coast region and one in Nairobi region were identified to assist in identifying drug injection locations and potential participants. Key informant interviews (KIIs) and Focus Group Discussions (FGDs) were also conducted using interview guides.ResultsA total of 646 individuals (344 in Nairobi and 302 at the coast) were recruited for the study between January and March 2010. Of these 590 (91%) were male and 56 (9%) were female. Findings showed that most PWIDs initiated injecting drug use between the ages of 20–29 years, with the youngest age of initiation being 11 years and oldest age being 53 years. Most commonly injected drug was heroin (98%), with a small (2%) percentage injecting cocaine. Other non-injecting methods such as smoking or combining these two drugs with other drugs such as cannabis or Rohypnol were also common. Most PWIDs used other substances (cigarettes, alcohol, and cannabis) before initiating injecting drug use. The adjusted national HIV prevalence of PWIDs was 18.3% (19.62% unadjusted) with PWIDs in Nairobi region registering 18.33% (20.58% unadjusted) compared PWIDs for Coastal region indicating 18.27% (18.59% - unadjusted). The gender based HIV prevalence showed that women were more at risk of acquiring HIV (44.51%-adjusted) compared to men (15.97%-adjusted). The age specific HIV prevalence showed that PWIDs who initiated injecting at 11–19 years (44.7% adjusted) were most at risk in Nairobi compared to those who initiated injecting at age 20–24 years (23.2% - adjusted) in the coastal region. While all PWIDs continue to be at risk in the two regions, those from the Western parts of Nairobi, Kenya were at a relatively higher risk given their increased propensity for sharing injecting equipment and solutions.ConclusionsCompared to the national HIV prevalence of (4.9%), the results show that People Who Inject Drugs (PWIDs) are at particularly high risk of infection in Kenya and there is urgent need for intervention (KenPHIA, 2018). This study also showed clear evidence that 70% of PWIDs are primary school educated, engage in high risk injecting and sexual behaviors comprising sharing of injecting equipment, unprotected heterosexual and homosexual sex. Given that initiation of injecting drug use begins early and peaks after formal school years (20–29 years), prevention programmes should be targeted at primary and secondary school students, college and out of school youth. Further, to protect People who inject drugs (PWIDs) from HIV infection, the country should introduce free Needle Syringe Programs (NSP) with provision of condoms and Methadone Assisted Therapy (MAT) as a substitute for drug use.

The influence of neighborhood socioeconomic disadvantage and social discomfort on high-risk injection behavior among people who inject drugs Jennifer DeCuir Research on the determinants of injection drug use behavior has traditionally concentrated on factors operating at the individual level. However, more recent studies have found that behaviors surrounding injection drug use are shaped, not only by individual-level characteristics, but also by the environment in which they occur. The risk environment paradigm, proposed by Rhodes and colleagues, describes how factors exogenous to the individual influence high-risk injection behavior and blood borne virus (BBV) transmission among people who inject drugs (PWID). To date, few elements of the risk environment have been evaluated as potential determinants of high-risk injection behavior. The purpose of this dissertation was to study the influence of two elements of the risk environment on unsafe injection practices among PWID – neighborhood socioeconomic disadvantage and social discomfort surrounding the acquisition of sterile syringes from syringe exchange programs (SEPs) and pharmacies. To this end, a systematic literature review was conducted on the relation between neighborhood context and injection drug use behavior. Research gaps and methodological challenges identified in this review were used to design analyses exploring relations among neighborhood disadvantage, social discomfort, and high-risk injection behavior. These analyses were conducted using data collected from 484 PWID enrolled in the Pharmacists as Resources Making Links to Community Services (PHARM-Link) study, combined with data from the American Community Survey. Poisson regression with robust error variance was used to estimate associations between measures of neighborhood socioeconomic disadvantage and high-risk injection behavior. SEP accessibility and drug-related police activity were evaluated as potential modifiers of these relations. Similar methods were used to estimate associations between measures of social discomfort and high-risk injection behavior, including neighborhood socioeconomic disadvantage as a potential effect modifier. The systematic literature review on neighborhood context and injection drug use behavior identified few articles pertaining to this relation (n=22). Selected studies primarily investigated the influence of structural aspects of the neighborhood environment on behaviors surrounding injection drug use, while aspects of the social environment and potential modifiers of neighborhood-behavior relations were understudied. Subsequent quantitative analyses revealed that neighborhood socioeconomic disadvantage was associated with safer injection behaviors among PWID. Injectors in disadvantaged neighborhoods reported less receptive syringe sharing and less unsterile syringe use than their counterparts in relatively better off neighborhoods. Drug-related police activity attenuated associations between neighborhood disadvantage and unsterile syringe use, while the direction of associations between neighborhood disadvantage and the use of unsafe syringe sources varied with levels of SEP accessibility. In neighborhoods with high SEP accessibility, neighborhood disadvantage was associated with decreased use of unsafe syringe sources, while in neighborhoods with low SEP accessibility, neighborhood disadvantage was associated with increased use of unsafe syringe sources. Social discomfort was not associated with high-risk injection behavior, but effect modification was detected between neighborhood disadvantage and two items measuring the quality of relationships between participants and syringe staff: “Pharmacists care about my health and well-being” and “The staff at syringe exchange programs seems to care about my health and well-being.” In disadvantaged neighborhoods, participants who reported positive relationships with syringe staff were less likely to engage in receptive syringe sharing. However, in relatively better off neighborhoods, positive relationships with syringe staff were associated with increased receptive syringe sharing. Overall, the results of this dissertation support the validity of the risk environment paradigm in shaping high-risk injection behavior among PWID. Future studies should continue to investigate contextual factors as determinants of behavior surrounding injection drug use. Understanding how aspects of local-area environments influence injection risk behavior will be essential to eliminating the transmission of BBVs among PWID.

The new direct-acting antiretroviral drugs for treating hepatitis C have generated considerable momentum for treating HCV infection among people who inject drugs and perhaps ‘ending the HCV epidemic’. There are, however, important epidemiological and behavior research problems that need to be addressed before ‘ending the HCV epidemic’ will be possible. The development of direct-acting antivirals (DAAs) that cure HCV infection in more than 90% of patients with minimal side effects has led to calls for ‘eliminating HCV infection’ or ‘ending HCV epidemics’ among people who inject drugs (PWID) 1. Some of the calls for eliminating HCV infection have included substantial allocations of new funds, e.g. New York State 2. Grebely et al. 3 have estimated the number and prevalence of people with a recent history (within past year) of injecting drug use who are living with hepatitis C virus (HCV) viremia and the proportion of people with recent injecting drug use among all people living with HCV infection at the global, regional and national levels. A major value of this study is its potential contribution as a baseline for ‘eliminating HCV’. While DAAs and the lessons from successfully controlling HIV among PWID in many areas 4 should certainly be useful in controlling HCV among PWID, the data presented in Grebely et al. illustrate that there is still a major amount of epidemiological and behavioral science that will be needed before ‘eliminating’ (or even ‘controlling’) HCV among PWID can be accomplished. First, what would ‘elimination/ending the epidemic’ of HCV among PWID look like? From early in the HIV epidemic among PWID, we had multiple examples, e.g. Glasgow, Scotland, Lund, Sweden, Sydney, Australia and Tacoma, WA, USA, where large-scale implementation of syringe access programs have kept HIV prevalence stable at less than 5% 5. The Grebely et al. data do not provide many (if any) examples of areas where HCV viremia has been stabilized at ‘ending the epidemic’ levels. Would 5% viremia in the local PWID population be a realistic goal? What sort of HCV combined prevention and care programs would be needed to stabilize HCV at 5% or less in a PWID population? Such a system would need to detect and treat existing cases of HCV infection as rapidly as new infections were occurring. Secondly, how will we develop better estimates of the size of PWID populations and the percentage of PWID who are HCV viremic? The uncertainty intervals in the Grebely et al. estimates are rather large, typically almost as large as the estimates themselves. Uncertainty in the estimates of the PWID population size and the percentage of PWID who are HCV viremic would create difficult problems for local officials who would have the task of allocating resources and planning logistical operations for rapidly scaling-up treatment for HCV-infected PWID. Thirdly, what new interventions can be developed to reduce HCV transmission behavior among viremic PWID? One of the important factors in HIV prevention was that PWID who learned that they were HIV-seropositive greatly reduced transmission behavior (passing their used needles and syringes to others) well before antiretroviral therapy (ART) was available 6. We have not yet seen the equivalent reductions in transmission behaviors among PWID who know that they are HCV-seropositive 7. How do we successfully encourage HCV viremic PWID to reduce transmission behavior? Fourthly, what interventions can be developed and implemented to reduce the very high HCV incidence rates among people who have recently begun injecting drugs 8? Many new injectors typically do not identify as ‘drug injectors’, and thus do not utilize HIV/HCV safer injection programs 9. Fifthly, what interventions will be implemented to reduce the rates that drug users transition to injecting drug use? There have been calls for more research on this topic 10, and there are current research studies addressing this subject. However, the objective should be to develop an evidence base for reducing initiation into injecting drug use that is comparable to the evidence base for medication assisted treatment and for syringe access programs. The new DAAs certainly give us the capability of treating very large numbers of HCV infected people who use drugs and greatly reduce morbidity and mortality, and programs to provide access to HCV treatment should be scaled-up in high-, middle- and low-income countries as quickly as feasible, and the additional research needed to learn how to ‘end HCV epidemics’ among PWID should be funded. Finally, and perhaps most importantly, while the above may be considered scientific tasks, it is important to emphasize that the research should be conducted in full collaboration with PWID and drug-user organizations. Such collaboration should not only greatly improve the quality of the research, but also greatly improve the likelihood that the findings will be incorporated into public health programs that could ‘end the HCV epidemic’ among people who use drugs. None.

IntroductionThere are limited data on young people who inject drugs (PWID) from low‐ and middle‐income countries where injection drug use remains a key driver of new HIV infections. India has a diverse injection drug use epidemic and estimates suggest that at least half of PWID are ≤30 years of age. We compared injection and sexual risk behaviours and HIV incidence between younger and older PWID and characterized uptake of HIV testing and harm reduction services to inform targeted HIV prevention efforts.MethodsWe analysed cross‐sectional data from 14,381 PWID recruited from cities in the Northeast and North/Central regions of India in 2013 using respondent driven sampling (RDS). We compared “emerging‐adult” (18 to 24 years, 26% of sample) and “young‐adult” PWID (25 to 30 years, 30% of sample) to older PWID (>30 years, 44% of sample) using logistic regression to evaluate factors associated with three recent risk behaviours: needle‐sharing, multiple sexual partners and unprotected sex. We estimated age‐stratified cross‐sectional HIV incidence using a validated multi‐assay algorithm.ResultsCompared to older adults, emerging‐adults in the Northeastern states were significantly more likely to share needles (males adjusted odds ratio [aOR] 1.82; females aOR 2.29, p < 0.01), have multiple sexual partners (males aOR 1.56; females aOR 3.75, p < 0.01), and engage in unprotected sex (males aOR 2.29, p < 0.01). In the North/Central states, young‐adult males were significantly more likely to needle‐share (aOR 1.23, p < 0.05) while emerging‐adult males were significantly more likely to have multiple sexual partners (aOR 1.74, p < 0.05). In both regions, emerging‐adults had the lowest HIV testing. Participation in harm reduction services was low across all age groups. Annual HIV incidence was higher in emerging‐ and young‐adult PWID in the North/Central region: emerging‐adults: 4.3% (95% confidence interval [CI] 3.0, 5.6); young‐adults: 4.9% (95% CI 3.7, 6.2); older adults: 2.1% (95% CI 1.4, 2.8).ConclusionsHigher HIV incidence and engagement in risky behaviours among younger PWID compared to older PWID, coupled with low utilization of harm reduction services highlight the importance of targeting this population in HIV programming. Age‐specific interventions focused on addressing the needs of young PWID are urgently needed to curb the HIV epidemic in this vulnerable population.

Background Blood borne infections such as HIV, Hepatitis B (HBV), and Hepatitis C (HCV) are of great importance to governments and their implementing partners, especially among people who use drugs (PWUD) and people who inject drugs (PWID). Prevalence and determinants of HIV, HBV, and HCV among PWUD and PWID in Ghana are not well established, the significance of this study. Method This assessment was a cross-sectional study implemented via the respondent driven sampling approach. A team of community advisory boards that comprised former users, current users, and civil society organizations were constituted to help in the implementation of the study. The study was conducted in four regions in Ghana. The assessment was based on a representation of populations of PWID and PWUD from the four regions. Efforts were made by the team to ensure adequate representation of women where feasible. A quantitative questionnaire was developed and used to obtain information on the respondents' sociodemographics, sexual behavior, substance use, and biological characteristics. The prevalence of HIV, HBV, and HCV among PWID and PWUD was determined using blood samples. First response and oral quick test for confirmation of HIV positivity were carried out, while SD bioline was used to test for the presence of HBV and HBC. Data were analyzed using the Bayesian generalized linear model via the binomial family of distributions under the logit link function with weak Cauchy and Normal distribution as prior. Results A total of 323 PWUD and PWID participants were interviewed across four regions of Ghana. The overall median age of the respondents was 36 (28, 43) years. The prevalence of HIV, HBV, and HCV infection in the study was 2.5%, 4.6%, and 5.9%, respectively. The prevalence of HIV, HBV, and HCV among drug users was 2.5% (95% CI: 0.7%–4.2%), 4.1% (95% CI: 1.8%–6.2%), and 6.7% (95% CI: 3.9%–9.4%), respectively. Most drug injectors and users started using and injecting drugs at ages less than 20 years and between 20 and 29 years, respectively. Drug users who identified themselves as part of the general population were 66% less likely to be tested HIV positive (POR = 0.34, CrI: 0.12–0.81) compared to sex workers. Part time employment respondents had fivefold odds (POR = 5.50, CrI: 1.20–16.16) of being HBV positive as against full-time employment. Conclusion Most of the injectors and users started drugs at an early age. Drug users and injectors are at higher risk of these infections because of associated risky sexual behaviors and risky injection practices. Harm reduction programs to help addicts who are willing to quit the practice are recommended.

People who inject drugs (PWID) are at higher risk of acquiring HIV due to risky injection and sexual practices. We measured HIV prevalence and behaviors related to acquisition and transmission risk at two time points (2007 and 2012) in Zanzibar, Tanzania. We conducted two rounds of behavioral and biological surveillance among PWID using respondent-driven sampling, recruiting 499 and 408 PWID, respectively. Through faceto- face interviews, we collected information on demographics as well as sexual and injection practices. We obtained blood samples for biological testing. We analyzed data using RDSAT and exported weights into STATA for multivariate analysis. HIV prevalence among sampled PWID in Zanzibar was 16.0 % in 2007 and 11.3 % in 2012; 73.2 % had injected drugs for 7 years or more in 2007, while in the 2012 sample this proportion was 36.9 %. In 2007, 53.6 % reported having shared a needle in the past month, while in the 2012 sample, 29.1 % reported having done so. While 13.3 % of PWID in 2007 reported having been tested for HIV infection and received results in the past year, this proportion was 38.0 % in 2012. Duration of injection drug use for 5 years or more was associated with higher odds of HIV infection in both samples. HIV prevalence and indicators of risk and preventive behaviors among PWID in Zanzibar were generally more favorable in 2012 compared to 2007-a period marked by the scale-up of prevention programs focusing on PWID. While encouraging, causal interpretation needs to be cautious and consider possible sample differences in these two cross-sectional surveys. HIV prevalence and related risk behaviors persist at levels warranting sustained and enhanced efforts of primary prevention and harm reduction.

BackgroundThe growing HIV epidemic in Eastern Europe and Central Asia has been driven by high rates of injection drug use. The Republic of Georgia has among the highest injection drug use rates globally, with a prevalence of 2.24%. The reach of evidence-based HIV prevention interventions like needle and syringe programs (NSP) among people who inject drugs (PWID) has remained below rates that could significantly impact the epidemic. Syringe vending machines (SVM) are an effective and cost-effective supplement to standard NSP; if acceptable to PWID, SVM could reach hard-to-reach PWID and cover geographic areas where fixed or mobile NSPs do not operate. The aim of this study was to assess the perceived acceptability of SVM among out-of-service (harm reduction or substance use treatment) PWID in Tbilisi, Georgia.MethodologyParticipants were recruited using respondent-driven sampling (RDS) to participate in cross-sectional, face-to-face interviews. We conducted individual interviews using a structured questionnaire that covered participants’ socio-demographics, drug use practices, and perceived acceptability of SVM. Uni-variate analyses were employed for data analysis.ResultsThe final sample (n = 149) was almost exclusively male with a mean age of 42.2 years and mean years of injection drug use of 14.4 years. Heroin, buprenorphine, and stimulants were the main drugs injected. Eighty-five percent of the sample had never received any harm reduction services, and 30% had never been tested for HIV. Fifteen percent of the sample reported sharing injection equipment with others during last month. All but one participant agreed that PWID would benefit from SVM and 145 (97%) said they would personally use SVM. Ninety percent of those sampled stated that they would use HIV self-tests if available from vending machines. The most highly endorsed features of SVM were provision of free injection equipment, no need to deal with pharmacies, uninterrupted 24/7 access, and availability of HIV self-testing kits.DiscussionPerceived acceptability of syringe vending machines was extremely high among PWID not currently receiving any harm reduction or treatment services, with strong support indicated for uninterrupted free access to sterile injection equipment, privacy, and anonymity. Introducing SVM in Georgia holds the potential to deliver significant public health benefits by attracting hard-to-reach PWID, reducing unsafe injection behavior, and contributing to HIV testing uptake and linkage to care.

Drug use stigma and its association with active hepatitis C virus infection and injection drug use behaviors among community-based people who inject drugs in India.

Background It is widely perceived that little is known about the epidemiology of HIV infection among people who inject drugs (PWID) in the Middle East and North Africa (MENA). The primary objective of this study was to assess the status of the HIV epidemic among PWID in MENA by describing HIV prevalence and incidence. Secondary objectives were to describe the risk behavior environment and the HIV epidemic potential among PWID, and to estimate the prevalence of injecting drug use in MENA. Methods This was a systematic review following the PRISMA guidelines and covering 23 MENA countries. PubMed, Embase, regional and international databases, as well as country-level reports were searched up to December 16, 2013. Primary studies reporting 1) the prevalence/incidence of HIV, other sexually transmitted infections, or hepatitis C virus (HCV) among PWIDs; or 2) the prevalence of injecting or sexual risk behaviors, or HIV knowledge among PWID; or 3) the number/proportion of PWID in MENA countries, were eligible for inclusion. The quality, quantity, and geographic coverage of the data were assessed at country level. After multiple level screening, 192 eligible reports were included in the review. There were 197 HIV prevalence measures on a total of 58,241 PWID extracted from reports, and an additional 226 HIV prevalence measures extracted from the databases. Findings We estimated that there are 626,000 PWID in MENA (range: 335,000-1,635,000, prevalence of 0.24 per 100 adults). We found evidence of HIV epidemics among PWID in at least one-third of MENA countries, most of which are emerging concentrated epidemics and with HIV prevalence overall in the range of 10-15%. Some of the epidemics have however already reached considerable levels including some of the highest HIV prevalence among PWID globally (87.1% in Tripoli, Libya). The relatively high prevalence of sharing needles/syringes (18-28% in the last injection), the low levels of condom use (20-54% ever condom use), the high levels of having sex with sex workers and with men who have sex with men (15-30% and 2-10% in the last year, respectively), and of selling sex (5-29% in the last year), indicate a high injecting and sexual risk environment. The prevalence of HCV (31-64%) and of sexually transmitted infections suggest high levels of risk behavior indicative of the potential for more and larger HIV epidemics. Conclusions Our study identified a large volume of HIV-related biological and behavioral data among PWID in the MENA region. The coverage and quality of the data varied between countries. There is robust evidence for HIV epidemics among PWID in multiple countries, most of which have emerged within the last decade and continue to grow. The lack of sufficient evidence in some MENA countries does not preclude the possibility of hidden epidemics among PWID in these settings. With the HIV epidemic among PWID in overall a relatively early phase, there is a window of opportunity for prevention that should not be missed through the provision of comprehensive programs, including scale-up of harm reduction services and expansion of surveillance systems.

Prevalence of hepatitis C virus in young people who inject drugs in four Colombian cities: A cross-sectional study using Respondent Driven Sampling

&lt;p dir="ltr"&gt;Hepatitis C virus (HCV) infection can progress to liver cirrhosis and hepatocellular carcinoma (HCC) and was in 2022 estimated to cause 240,000 deaths worldwide. The virus is bloodborne, and a main transmission route is injection drug use through sharing of unsterile needles and syringes. The prevalence of HCV infection is consequently high in people who inject drugs (PWID). The World Health Organization (WHO) has set a goal to eliminate HCV as a public health threat, by the year 2030, which includes a 90% reduction in new chronic infections, a 65% reduction in mortality, and a target of &gt;80% treated. To achieve this goal a deeper understanding of the epidemiology of HCV in PWID, the main drivers of the epidemic, is essential. The aims of this thesis were to study the prevalence and incidence of HCV infection, liver-related mortality, and HCV treatment uptake in PWID.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In Study I&lt;/b&gt;, we demonstrated a high prevalence of HCV infection (11%) in detainees in Stockholm County, which highlights that prisons could constitute a target facility for testing and treatment of HCV infection.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In Study II&lt;/b&gt;, we reported a high liver-related mortality in PWID with HCV infection. Amphetamine users had an even higher liver-related mortality than opioid users, probably as they lived longer and were less likely to die from drug-related causes at younger ages, which enabled late consequences of HCV infection to emerge. In addition, amphetamine users had a higher alcohol-consumption, which was a risk factor for liver-related death.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In Study III&lt;/b&gt;, we noted a great decline in HCV prevalence in PWID in Stockholm (from 62% to 30%) in recent years, following the introduction of direct-acting antiviral (DAA) treatment and the startup of a needle syringe program (NSP) in Stockholm. However, no significant reduction in incidence was observed, indicating that treatment efforts to date have primarily reached individuals with lower injection-related risk behaviors, while those at highest risk of onward transmission may remain untreated.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In study IV&lt;/b&gt;, we reported that &gt;80% of individuals notified with HCV infection in Sweden have initiated treatment, indicating that Sweden has reached the WHO HCV treatment target. Median time to treatment initiation was only a few months in recent years. The odds of receiving treatment were, however, lower among people with drug use diagnoses.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In conclusion&lt;/b&gt;, this thesis demonstrates high HCV prevalence and incidence rates in PWID, as well as elevated liver-related mortality. Along with an increasing treatment uptake in recent years, the HCV prevalence has decreased, suggesting that a scale up of HCV treatment is effective. However, the lack of reduction in incidence among PWID highlights the importance of further expanded testing and treatment efforts. To achieve the WHO elimination goal, PWID need to remain a key focus, especially those with the highest risk behaviors for viral transmission, and high-prevalence settings such as prisons, NSPs, and addiction treatment centers should be targeted.&lt;/p&gt;&lt;h3&gt;List of scientific papers&lt;/h3&gt;&lt;p dir="ltr"&gt;I. &lt;b&gt;Gahrton C,&lt;/b&gt; Westman G, Lindahl K, Öhrn F, Dalgard O, Lidman C, Nilsson LH, Said K, Duberg AS, Aleman S. Prevalence of Viremic hepatitis C, hepatitis B, and HIV infection, and vaccination status among prisoners in Stockholm County. BMC Infect Dis. 2019;19(1):955. &lt;a href="https://doi.org/10.1186/s12879-019-4581-3" rel="noreferrer" target="_blank"&gt;https://doi.org/10.1186/s12879-019-4581-3&lt;/a&gt;&lt;/p&gt;&lt;p dir="ltr"&gt;II. &lt;b&gt;Gahrton C,&lt;/b&gt; Håkansson A, Kåberg M, Jerkeman A, Häbel H, Dalgard O, Duberg AS*, Aleman S*. Mortality among amphetamine users with hepatitis C virus infection: A nationwide study. PLoS One.2021;16(6):e0253710. &lt;a href="https://doi.org/10.1371/journal.pone.0253710" rel="noreferrer" target="_blank"&gt;https://doi.org/10.1371/journal.pone.0253710&lt;/a&gt;&lt;/p&gt;&lt;p dir="ltr"&gt;III. &lt;b&gt;Gahrton C,&lt;/b&gt; Navér G, Warnqvist A, Dalgart O, Aleman S, Kåberg M. Changes in hepatitis C virus prevalence and incidence among people who inject drugs in the direct acting antiviral era. International Journal on Drug Policy, 2024;128:104433. &lt;a href="https://doi.org/10.1016/j.drugpo.2024.104433" rel="noreferrer" target="_blank"&gt;https://doi.org/10.1016/j.drugpo.2024.104433&lt;/a&gt;&lt;/p&gt;&lt;p dir="ltr"&gt;IV. &lt;b&gt;Gahrton C,&lt;/b&gt; Kåberg M, Lybeck C, Lindahl K, Patil S, Dalgard O, Aleman S*, Duberg AS*. Treatment uptake among individuals notified with HCV infection 1990- 2022 in Sweden. Infectious diseases. 2025:1-11. &lt;a href="https://doi.org/10.1080/23744235.2025.2569504" rel="noreferrer" target="_blank"&gt;https://doi.org/10.1080/23744235.2025.2569504&lt;/a&gt;&lt;/p&gt;&lt;p dir="ltr"&gt;*shared last authorship&lt;/p&gt;

&lt;p dir="ltr"&gt;Hepatitis C virus (HCV) infection can progress to liver cirrhosis and hepatocellular carcinoma (HCC) and was in 2022 estimated to cause 240,000 deaths worldwide. The virus is bloodborne, and a main transmission route is injection drug use through sharing of unsterile needles and syringes. The prevalence of HCV infection is consequently high in people who inject drugs (PWID). The World Health Organization (WHO) has set a goal to eliminate HCV as a public health threat, by the year 2030, which includes a 90% reduction in new chronic infections, a 65% reduction in mortality, and a target of &gt;80% treated. To achieve this goal a deeper understanding of the epidemiology of HCV in PWID, the main drivers of the epidemic, is essential. The aims of this thesis were to study the prevalence and incidence of HCV infection, liver-related mortality, and HCV treatment uptake in PWID.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In Study I&lt;/b&gt;, we demonstrated a high prevalence of HCV infection (11%) in detainees in Stockholm County, which highlights that prisons could constitute a target facility for testing and treatment of HCV infection.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In Study II&lt;/b&gt;, we reported a high liver-related mortality in PWID with HCV infection. Amphetamine users had an even higher liver-related mortality than opioid users, probably as they lived longer and were less likely to die from drug-related causes at younger ages, which enabled late consequences of HCV infection to emerge. In addition, amphetamine users had a higher alcohol-consumption, which was a risk factor for liver-related death.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In Study III&lt;/b&gt;, we noted a great decline in HCV prevalence in PWID in Stockholm (from 62% to 30%) in recent years, following the introduction of direct-acting antiviral (DAA) treatment and the startup of a needle syringe program (NSP) in Stockholm. However, no significant reduction in incidence was observed, indicating that treatment efforts to date have primarily reached individuals with lower injection-related risk behaviors, while those at highest risk of onward transmission may remain untreated.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In study IV&lt;/b&gt;, we reported that &gt;80% of individuals notified with HCV infection in Sweden have initiated treatment, indicating that Sweden has reached the WHO HCV treatment target. Median time to treatment initiation was only a few months in recent years. The odds of receiving treatment were, however, lower among people with drug use diagnoses.&lt;/p&gt;&lt;p dir="ltr"&gt;&lt;b&gt;In conclusion&lt;/b&gt;, this thesis demonstrates high HCV prevalence and incidence rates in PWID, as well as elevated liver-related mortality. Along with an increasing treatment uptake in recent years, the HCV prevalence has decreased, suggesting that a scale up of HCV treatment is effective. However, the lack of reduction in incidence among PWID highlights the importance of further expanded testing and treatment efforts. To achieve the WHO elimination goal, PWID need to remain a key focus, especially those with the highest risk behaviors for viral transmission, and high-prevalence settings such as prisons, NSPs, and addiction treatment centers should be targeted.&lt;/p&gt;&lt;h3&gt;List of scientific papers&lt;/h3&gt;&lt;p dir="ltr"&gt;I. &lt;b&gt;Gahrton C,&lt;/b&gt; Westman G, Lindahl K, Öhrn F, Dalgard O, Lidman C, Nilsson LH, Said K, Duberg AS, Aleman S. Prevalence of Viremic hepatitis C, hepatitis B, and HIV infection, and vaccination status among prisoners in Stockholm County. BMC Infect Dis. 2019;19(1):955. &lt;a href="https://doi.org/10.1186/s12879-019-4581-3" rel="noreferrer" target="_blank"&gt;https://doi.org/10.1186/s12879-019-4581-3&lt;/a&gt;&lt;/p&gt;&lt;p dir="ltr"&gt;II. &lt;b&gt;Gahrton C,&lt;/b&gt; Håkansson A, Kåberg M, Jerkeman A, Häbel H, Dalgard O, Duberg AS*, Aleman S*. Mortality among amphetamine users with hepatitis C virus infection: A nationwide study. PLoS One.2021;16(6):e0253710. &lt;a href="https://doi.org/10.1371/journal.pone.0253710" rel="noreferrer" target="_blank"&gt;https://doi.org/10.1371/journal.pone.0253710&lt;/a&gt;&lt;/p&gt;&lt;p dir="ltr"&gt;III. &lt;b&gt;Gahrton C,&lt;/b&gt; Navér G, Warnqvist A, Dalgart O, Aleman S, Kåberg M. Changes in hepatitis C virus prevalence and incidence among people who inject drugs in the direct acting antiviral era. International Journal on Drug Policy, 2024;128:104433. &lt;a href="https://doi.org/10.1016/j.drugpo.2024.104433" rel="noreferrer" target="_blank"&gt;https://doi.org/10.1016/j.drugpo.2024.104433&lt;/a&gt;&lt;/p&gt;&lt;p dir="ltr"&gt;IV. &lt;b&gt;Gahrton C,&lt;/b&gt; Kåberg M, Lybeck C, Lindahl K, Patil S, Dalgard O, Aleman S*, Duberg AS*. Treatment uptake among individuals notified with HCV infection 1990- 2022 in Sweden. Infectious diseases. 2025:1-11. &lt;a href="https://doi.org/10.1080/23744235.2025.2569504" rel="noreferrer" target="_blank"&gt;https://doi.org/10.1080/23744235.2025.2569504&lt;/a&gt;&lt;/p&gt;&lt;p dir="ltr"&gt;*shared last authorship&lt;/p&gt;

BackgroundRespondent Driven Sampling (RDS) is an effective sampling strategy to recruit hard-to-reach populations but the impact of the COVID-19 pandemic on the use of this strategy in the collection of data involving human subjects, particularly among marginalized and vulnerable populations, is not known. Based on an ongoing study using RDS to recruit and study the interactions between HIV infection, injection drug use, and the microbiome in Puerto Rico, this paper explores the effectiveness of RDS during the pandemic and provided potential strategies that could improve recruitment and data collection.ResultsRDS was employed to evaluate its effectiveness in recruiting a group of people who inject drugs (PWID) and controls (N = 127) into a study in the midst of the COVID-19 pandemic. The participants were distributed among three subsets: 15 were HIV+ and PWID, 58 were HIV- PWID, and 54 were HIV+ and not PWID.FindingsResults show that recruitment through peer networks using RDS was possible across all sub-groups. Yet, while those in the HIV+ PWID sub-group managed to recruit from other-sub groups of HIV- PWID and HIV+, this occurred at a lower frequency.ConclusionDespite the barriers introduced by COVID-19, it is clear that even in this environment, RDS continues to play a powerful role in recruiting hard-to-reach populations. Yet, more attention should be paid at how future pandemics, natural disasters, and other big events might affect RDS recruitment of vulnerable and hard-to-reach populations.

BackgroundPeople who use non-injection drug use are at risk of transitioning to injecting drugs, which increases their vulnerability to HIV and other blood-borne infections. This study aimed to investigate the correlates of the duration between the first drug use and the first drug injection among people who inject drugs (PWID) in Iran, as well as the reasons for injection initiation.MethodsWe analyzed data from the fourth national bio-behavioral surveillance survey among PWID in Iran, conducted in 2020 across 11 cities using respondent-driven sampling (n = 2,684). A generalized linear mixed model with a gamma-distributed dependent variable and log link function was used to investigate the correlates of transition time from non-injection to injection drug use.ResultsAmong 2,356 participants included in the analysis, the mean ± SD of the duration between the first drug use and the first drug injection was 9.37 ± 6.8 years. Factors associated with earlier injection initiation included: age under 30 years (p-value < 0.001), being single (p-value < 0.001) or divorced/widowed (p-value = 0.007), history of incarceration (p-value = 0.001), sexual debut before age 18 (p-value < 0.001), and history of depression (p-value < 0.001). Peer influence (665;29.1%) and pleasure-seeking behavior (534; 23.3%) were the most common motives for injection initiation.ConclusionsThe transition to injection drug use among PWID in Iran often occurs within a decade of initial drug use and is influenced by demographic, social, and psychological factors. Prevention strategies should focus on early intervention for at-risk youth, address mental health needs, and leverage peer influence. Policymakers should prioritize evidence-based, multi-faceted approaches that target both individual and structural factors to delay or prevent the transition to injection drug use and reduce associated health risks.