Invasive Group A Streptococcal Infections Among People Who Inject Drugs and People Experiencing Homelessness in the United States, 2010-2017.

Public health data signal increases in the number of people who inject drugs (PWID) in the United States during the past decade. An updated PWID population size estimate is critical for informing interventions and policies aiming to reduce injection-associated infections and overdose, as well as to provide a baseline for assessments of pandemic-related changes in injection drug use. We used a modified multiplier approach to estimate the number of adults who injected drugs in the United States in 2018. We deduced the estimated number of nonfatal overdose events among PWID from 2 of our previously published estimates: the number of injection-involved overdose deaths and the meta-analyzed ratio of nonfatal to fatal overdose. The number of nonfatal overdose events was divided by prevalence of nonfatal overdose among current PWID for a population size estimate. There were an estimated 3 694 500 (95% confidence interval [CI], 1 872 700-7 273 300) PWID in the United States in 2018, representing 1.46% (95% CI, .74-2.87) of the adult population. The estimated prevalence of injection drug use was highest among males (2.1%; 95% CI, 1.1-4.2), non-Hispanic Whites (1.8%; 95% CI, .9-3.6), and adults aged 18-39 years (1.8%; 95% CI, .9-3.6). Using transparent, replicable methods and largely publicly available data, we provide the first update to the number of people who inject drugs in the United States in nearly 10 years. Findings suggest the population size of PWID has substantially grown in the past decade and that prevention services for PWID should be proportionally increased.

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.

Background People who inject drugs (PWID) are at higher risk for severe bacterial infectious diseases (ID), which drive expensive hospitalizations. Identification of PWID allows for linkage to clinical interventions, such as multidisciplinary ID-addiction treatment teams, which improve clinical outcomes. Yet injection drug use (IDU) is often captured only in the text of clinical notes and is not easily queried. We sought to demonstrate text-based IDU classification by a large language model (LLM), a type of artificial intelligence.Figure 1Workflow of the Classification and Labeling Procedures and Full Text of the Prompt. IDU, injection drug use; LLM, large language model; LLaMA 3.3 is the LLM used.Figure 2Confusion matrix of LLM labeling performance compared to human classification (treated as the ground truth). IDU, injection drug use; LLM, large language model. Methods Hospital encounters at an academic medical center between 2018 and 2022 were included if they featured ICD codes for both acute infections and opioid use. Encounters were reviewed by trained research assistants and classified as “IDU” or “non-IDU” based on clinical notes. A balanced sample of 100 encounters was selected randomly for the LLM classification. The hospital admission note was extracted from the electronic medical record (Epic). A zero-shot prompt instructed the LLM (LLaMA 3.3; Meta, 70B parameters) to label each encounter as “IDU” or “non-IDU” (Figure 1). LLM labels were compared to human classifications. Positive and negative predictive values (PPV, NPV) were estimated for varying IDU prevalence. 95% confidence intervals were estimated with the Wilson-Brown method.Figure 3LLM labeling compared to human classification. Error bars, 95% CIFigure 4Estimated PPV and NPV of LLM labeling compared to classification in theoretical cohorts of varying IDU prevalence. IDU, injection drug use; LLM, large language model; NPV, negative predictive value; PPV, positive predictive value. Error bars, 95% CI. Results Of the 50 IDU and 50 non-IDU encounters, the LLM labeling yielded 34 true positives, 16 false negatives, 40 true negatives, and 10 false positives (Figure 2). Sensitivity was 0.68 (95% CI 0.54-0.79); specificity 0.80 (95% CI 0.67-0.89; Figure 3). Accuracy of the LLM label was 0.74; F1-score 0.72. Estimates of PPV with IDU prevalence of 50%, 10%, and 1% were 0.77, 0.27, and 0.03; estimates of NPV were 0.71, 0.96, and >0.99 (Figure 4). Conclusion In this small pilot study, an LLM demonstrated moderate performance on identifying PWID. The performance would likely limit usability in screening cohorts with real-world prevalence of IDU (1-10%). Future work will seek improved performance by refining the LLM prompt, evaluating other LLMs, and examining additional data (eg, ID consultation notes). Additional validation is needed with larger, distinct datasets. LLMs holds promise to identify hospitalized PWID to improve health outcomes. Disclosures All Authors: No reported disclosures

We examined whether gang membership history was associated with earlier age of first drug use, first drug injection, and shorter time to injection (TTI) drug use among people who inject drugs (PWID). PWID ( N = 438) were interviewed in California (2011-2013). Surveys addressed demographics, current/former drug use practices, gang membership, and parental drug use. Multivariate analyses were conducted to identify whether gang membership history was associated with age at first drug use, first injection drug use, and TTI. Gang membership was reported by 23% of sample. Gang membership history was associated with earlier ages of first drug use (–1.35 years; 95% confidence interval [CI]= [−0.50, −2.20]), age at first injection (–1.89 years; 95% CI = [0.00, −3.78]), but not TTI. Gang involvement facilitates drug use including earlier age of first injection drug use.

BackgroundInfective endocarditis (IE) remains highly morbid, but few studies have evaluated factors associated with IE mortality. We examined correlates of 90-day mortality among people who inject drugs (PWID) and people who do not inject drugs (non-PWID).MethodsWe queried the electronic medical record for cases of IE among adults ≥18 years of age at 2 academic medical centers in Seattle, Washington, from 1 January 2014 to 31 July 2019. Cases were reviewed to confirm a diagnosis of IE and drug use status. Deaths were confirmed through the Washington State death index. Descriptive statistics were used to characterize IE in PWID and non-PWID. Kaplan-Meier log-rank tests and Cox proportional hazard models were used to assess correlates of 90-day mortality.ResultsWe identified 507 patients with IE, 213 (42%) of whom were PWID. Sixteen percent of patients died within 90 days of admission, including 14% of PWID and 17% of non-PWID (P = .50). In a multivariable Cox proportional hazard model, injection drug use was associated with a higher mortality within the first 14 days of admission (adjusted hazard ratio [aHR], 2.33 [95% confidence interval {CI}, 1.16–4.65], P = .02); however, there was no association between injection drug use and mortality between 15 and 90 days of admission (aHR, 0.63 [95% CI, .31–1.30], P = .21).ConclusionsOverall 90-day mortality did not differ between PWID and non-PWID with IE, although PWID experienced a higher risk of death within 14 days of admission. These findings suggest that early IE diagnosis and treatment among PWID is critical to improving outcomes.

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.

BackgroundThe United States’ opioid epidemic has led to an increase in people who inject drugs (PWID) and opioid-associated infections, including infectious endocarditis (IE). Cardiac surgery is often indicated in IE to improve outcomes but is controversial in PWID due to the concerns about continued injection drug use leading to risk for reinfection and decreased survival. In response, we assessed the long-term survival after cardiac valve surgery in PWID compared with people who do not inject drugs (non-PWID) in the published literature.MethodsWe performed a systematic review and meta-analysis (MA) of studies that reported survival data after surgery for IE in PWID. We searched PUBMED up to April 2018. We extracted Kaplan–Meier (KM) curves from included studies. From the KM curves, we used an algorithm to estimate individual participant data (eIPD). In a one-step approach, we ran a Cox proportional hazards (CPH) model analysis of the eIPD with study random effects. In a two-step approach, we fitted CPH models by individual study; then, we ran a mixed-effects MA model of the log hazard ratios (HR) and standard errors.ResultsWe identified 11 retrospective studies. Of these, six reported comparisons of PWID vs. non-PWID, and five reported results for PWID only. Based on eIPD, we included 407 PWID and 1,877 non-PWID. Mean age for PWID was 36.7 years (95% CI 34.4–39.1) and for non-PWID was 52.0 years (95% CI 45.3–59.4). There were 144 deaths (35.3%) in PWID and 559 (29.8%) deaths in non-PWID. We present by study and by group KM curves of eIPD (Figures 1 and 2). In one-step MA (included all 11 studies), the HR for PWID was 1.13 (95% CI 0.92–1.39). In two-step MA (included six comparison studies), heterogeneity was high (I2 = 72%); and there was no significant between-group difference (HR 1.29, 95% CI 0.80–2.07) (Figure 3).ConclusionSurvival time post-surgery of PWID was similar to that of non-PWID. These estimates are concerning, as PWID on average are much younger than non-PWID with IE. Future studies should explore interventions to improve outcomes in PWID after surgery, including treatment of addiction during and after the index hospitalization and provision of naloxone at the time of discharge.DisclosuresAll authors: No reported disclosures.

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.

Reply to: ‘High prevalence of hepatitis C infection among multidrug-resistant tuberculosis patients’

Background: Previous research has shown that People Who Inject Drugs (PWID) are subject to public stigma, which affects access to, and provision and quality of, treatment and support services. Less is known about the socio-cognitive processes that support the development and maintenance of public stigma toward PWID. The present study investigated the role of disgust sensitivity in implicit disgust to injecting drug use. Methods: 126 participants took part in an online Implicit Association Task (IAT) measuring implicit disgust to pictorial stimuli of injecting drug use or medical injecting. Participants also completed The Disgust Scale Revised, Injecting Phobia Scale (Short Form), Attitudes to People Who Use Drugs (PWUD) scale and a substance use inventory. Results: Average IAT score was negative indicating significantly higher implicit disgust to injecting drug use. Hierarchical linear regression found that injecting phobia predicted implicit disgust to injecting drug use. Questionnaire measures of disgust did not predict implicit disgust. While animal reminder disgust and injecting phobia were significantly correlated with each other, animal reminder disgust did not predict implicit disgust scores. Conclusions: On the basis of our findings, stigma toward PWID may not be a result of feelings of disgust toward injecting drug use. We discuss findings in the context of the underlying cortical processes supporting implicit and explicit representations of disgust. Future research should seek to investigate neurophysiological evidence for disgust to and stigmatization of injecting drug use and the potential role of domains of disgust in this.

Objectives: High levels of morbidity and mortality associated with injection drug use continue to represent a significant public health challenge in many settings worldwide. Previous studies have shown an association between cannabis use and decreased risk of some drug-related harms. We sought to evaluate the association between high-intensity cannabis use and the frequency of injection drug use among people who inject drugs (PWID). Methods: The data for this analysis were collected from three prospective cohorts of PWID in Vancouver, Canada, between September 2005 and May 2018. Generalized linear mixed-effects models were used to analyze the association between daily cannabis use and the frequency of injecting illegal drugs (i.e., self-reported average number of injections per month). Results: Among the 2,619 active PWID, the frequency of injection drug use was significantly lower among people who use cannabis daily compared with people who use it less than daily (adjusted odds ratio [AOR]=0.84, 95% confidence interval [CI]: 0.73-0.95). Sub-analyses indicated that this effect was restricted to the frequency of illegal opioid injection (AOR=0.78, 95% CI: 0.68-0.90); the association between daily cannabis use and the frequency of illegal stimulant injection was not significant (AOR=1.08, 95% CI 0.93-1.25). Discussion: The findings from these prospective cohorts suggest that people who use cannabis daily were less likely to report daily injection of illegal drugs compared with people who use it less than daily. These results suggest the potential value of conducting experimental research to test whether controlled administration of cannabinoids impacts the frequency of illegal opioid injection among PWID.

Introduction: Injecting drug use is a public health concern due to its clinical, social, economic, and legal consequences. Objective: (1) To evaluate the prevalence of infections associated with injecting drug use; and (2) To assess the social profile of substance users and high-risk behaviors among people who inject drugs (PWID) receiving opioid substitution therapy (OST). Materials and Methods: A cross-sectional study was conducted among 100 PWID who were deemed eligible using inclusion and exclusion criteria. Data were collected through an interviewer-administered structured questionnaire after obtaining informed written consent. Results: The results revealed that 14% of PWID had human immunodeficiency virus (HIV), 7% had tuberculosis, and 2% had hepatitis B virus (HBV). None of the PWID self-reported hepatitis C virus (HCV) infection. Importantly, 71% of PWID were living on the streets (i.e. homeless), and 41% of PWID had a history of sharing needles with other users in the preceding 3 months. Unmarried or single PWID had significantly increased risk of homelessness (χ2 = 4.570; P = 0.032) and reported high-risk sexual practices with commercial sexual partners in the preceding 3 months (χ2 = 4.163; P = 0.041). Homeless PWID had significantly increased frequency of injecting practices (P = 0.020). Conclusion: Despite the higher global prevalence of HCV compared with HBV and HIV among PWID, HCV testing is not currently conducted at most OST centers in India. Access to free needles and syringes should be enhanced to reduce the morbidity associated with injecting drug use.

BackgroundGroup A Streptococcus is responsible for severe and potentially lethal invasive conditions requiring intensive care unit (ICU) admission, such as streptococcal toxic shock-like syndrome (STSS). A rebound of invasive group A streptococcal (iGAS) infection after COVID-19-associated barrier measures has been observed in children. Several intensivists of French adult ICUs have reported similar bedside impressions without objective data. We aimed to compare the incidence of iGAS infection before and after the COVID-19 pandemic, describe iGAS patients’ characteristics, and determine ICU mortality associated factors.MethodsWe performed a retrospective multicenter cohort study in 37 French ICUs, including all patients admitted for iGAS infections for two periods: two years before period (October 2018 to March 2019 and October 2019 to March 2020) and a one-year after period (October 2022 to March 2023) COVID-19 pandemic. iGAS infection was defined by Group A Streptococcus isolation from a normally sterile site. iGAS infections were identified using the International Classification of Diseases and confirmed with each center's microbiology laboratory databases. The incidence of iGAS infections was expressed in case rate.ResultsTwo hundred and twenty-two patients were admitted to ICU for iGAS infections: 73 before and 149 after COVID-19 pandemic. Their case rate during the period before and after COVID-19 pandemic was 205 and 949/100,000 ICU admissions, respectively (p < 0.001), with more frequent STSS after the COVID-19 pandemic (61% vs. 45%, p = 0.015). iGAS patients (n = 222) had a median SOFA score of 8 (5–13), invasive mechanical ventilation and norepinephrine in 61% and 74% of patients. ICU mortality in iGAS patients was 19% (14% before and 22% after COVID-19 pandemic; p = 0.135). In multivariate analysis, invasive mechanical ventilation (OR = 6.08 (1.71–21.60), p = 0.005), STSS (OR = 5.75 (1.71–19.22), p = 0.005), acute kidney injury (OR = 4.85 (1.05–22.42), p = 0.043), immunosuppression (OR = 4.02 (1.03–15.59), p = 0.044), and diabetes (OR = 3.92 (1.42–10.79), p = 0.008) were significantly associated with ICU mortality.ConclusionThe incidence of iGAS infections requiring ICU admission increased by 4 to 5 after the COVID-19 pandemic. After the COVID-19 pandemic, the rate of STSS was higher, with no significant increase in ICU mortality rate.

BackgroundThe age-adjusted rate of drug overdose deaths in the United States tripled from 1999 to 2016. Public health surveillance data indicate that an increasing proportion of infections due to bacterial and fungal pathogens is associated with injection drug use (IDU). We describe healthcare encounters (HCEs) of PWID as potential opportunities to prevent infections related to IDU by identifying risks and treating SUD, including with medication-assisted treatment (MAT) for opioid use disorder.MethodsAt six hospitals in western New York, we abstracted medical records from hospital admissions and emergency department (ED) visits for PWID (i.e., IDU in the preceding year) who had positive cultures for Staphylococcus aureus (any clinical specimen, April–July 2017), group A Streptococcus (invasive specimens, all of 2017) or Candida spp. (blood specimens, all of 2017). We reviewed hospital admission and ED records for 1 year preceding the positive culture to identify visits during which opportunities to prevent infection and treat SUD by addressing SUD and IDU were missed.ResultsWe identified 99 PWID with positive cultures. The median age was 33 years (range 19–68) and 61 were female. Sixty-nine had a skin and soft-tissue infection, 44 had a bloodstream infection, and 20 had both. Thirty-one PWID left against medical advice during a hospital admission or an ED visit. Seventy-nine PWID were hospitalized, of whom 4 died. Ninety-five used opioids and 71 used cocaine in the preceding year. Seventy-five PWID had an HCE in the 12 months prior to the index visit, with a median of two HCE per person (interquartile range 1–4); 53 of PWID had a previous HCE for infection and 28 for opioid overdose. SUD was documented during a prior HCE at the same hospital for 61 PWID, but only 10 (16%) were offered MAT during any prior HCE and for 24 (39%) there was no documentation that any form of treatment for SUD was offered.ConclusionIn this cohort, PWID frequently had one or more healthcare encounters documented at the same hospital in the year prior to a serious bacterial or fungal infection. These prior HCEs were often for infections or overdose that signaled the need for MAT, demonstrating that there are critical missed opportunities to identify risks, prevent infection, and treat SUD.DisclosuresAll Authors: No reported Disclosures.

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.