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BackgroundPeople who inject drugs (PWID) are at high risk for hepatitis C virus (HCV) infection and its complications in many countries, including Iran. This pilot study aimed to evaluate the effect of a community-based HCV model of care on HCV testing and treatment initiation among PWID in Kerman, Iran.MethodsThis study is part of the Rostam study and is a non-randomized trial evaluating the effect of on-site HCV- antibody rapid testing, venipuncture for HCV RNA testing, and treatment eligibility assessment on HCV testing and treatment initiation among PWID. Recruitment, interviews, and HCV screening, diagnosis, and treatment were all conducted at a community-based drop-in center (DIC) serving PWID clients.ResultsA total of 171 PWID (median age of 39 years and 89.5% male) were recruited between July 2018 and May 2019. Of 62 individuals who were HCV antibody positive, 47 (75.8%) were HCV RNA positive. Of RNA-positive individuals, 36 (76.6%) returned for treatment eligibility assessment. Of all the 36 participants eligible for treatment, 34 (94.4%) initiated HCV antiviral therapy. A sustained virologic response at 12 weeks post-treatment was 76.5% (26/34) in the intention-to-treat (ITT group) analysis and 100% (23/23) in the per-protocol (PP group) analysis.ConclusionOur integrated on-site community-based HCV care model within a DIC setting suggested that HCV care including HCV testing and treatment uptake can be successfully delivered outside of hospitals or specialized clinics; a model which is more likely to reach PWID and can provide significant progress towards HCV elimination among this population.

PurposeHepatitis C virus (HCV) is the most common blood-borne infection in the United States, and a leading cause of liver disease, transplant, and mortality. CDC HCV elimination goals include reducing HCV-related mortality by 65% (from 2015) by 2030.MethodsWe used vital registry data (CDC WONDER) to estimate overall and demographic-specific HCV-related mortality from 1999 to 2019 in San Francisco and then used an exponential model to project progress toward HCV elimination. Local trends were compared to state and national trends.ResultsBetween 1999 and 2019, there were 1819 HCV-related deaths in San Francisco, representing an overall age-adjusted mortality rate of 9.4 (95% CI 9.0, 9.9) per 100,000 population. The age-adjusted HCV-related mortality rates were significantly higher among males (13.7), persons aged 55 years and older (28.0), Black and/or African Americans (32.2) compared to other racial groups, and Hispanic/Latinos (11.6) compared to non-Hispanic and/or Latinos. Overall and in most subgroups, mortality rates were lowest between 2015 and 2019. Since 2015, San Francisco observed a significantly larger reduction in agbe-adjusted HCV-related mortality than California or the U.S. Projected age-adjusted HCV-related mortality rates for San Francisco for 2020 and 2030 were 4.7 (95% CI 3.5, 6.2) and 1.1 (95% CI 0.7, 1.8), respectively.ConclusionsBased on trends between 2015 and 2019, San Francisco, California, and the U.S. are projected to achieve 65% reduction in HCV-mortality at or before 2030. Based on current trends, San Francisco is projected to achieve this goal earlier.

BackgroundIn 2017, San Francisco's initiative to locally eliminate hepatitis C virus (HCV) as a public health threat, End Hep C SF, generated an estimate of city-wide HCV prevalence in 2015, but only incorporated limited information about population HCV treatment. Using additional data and updated methods, we aimed to update the 2015 estimate to 2019 and provide a more accurate estimate of the number of people with untreated, active HCV infection overall and in key subgroups-people who inject drugs (PWID), men who have sex with men (MSM), and low socioeconomic status transgender women (low SES TW).MethodsOur estimates are based on triangulation of data from blood bank testing records, cross-sectional and longitudinal observational studies, and published literature. We calculated subpopulation estimates based on biological sex, age and/or HCV risk group. When multiple sources of data were available for subpopulation estimates, we calculated an average using inverse variance weighting. Plausible ranges (PRs) were conservatively estimated to convey uncertainty.ResultsThe total number of people estimated to have anti-HCV antibodies in San Francisco in 2019 was 22,585 (PR:12,014-44,152), with a citywide seroprevalence of 2.6% (PR:1.4%-5.0%)-similar to the 2015 estimate of 21,758 (PR:10,274-42,067). Of all people with evidence of past or present infection, an estimated 11,582 (PR:4,864-35,094) still had untreated, active HCV infection, representing 51.3% (PR:40.5%-79.5%) of all people with anti-HCV antibodies, and 1.3% (PR:0.6%-4.0%) of all San Franciscans. PWID comprised an estimated 2.8% of the total population of San Francisco, yet 73.1% of people with anti-HCV antibodies and 90.4% (n = 10,468, PR:4,690-17,628) of untreated, active HCV infections were among PWID. MSM comprised 7.8% of the total population, yet 11.7% of people with anti-HCV antibodies and 1.0% (n = 119, PR:0-423) of those with untreated active infections. Low SES TW comprised an estimated 0.1% of the total population, yet 1.4% of people with HCV antibodies and 1.6% (n = 183, PR:130-252) of people with untreated active infections.ConclusionsDespite the above-average number (2.6%) of people with anti-HCV antibodies, we estimate that only 1.3% (PR:0.6%-4.0%) of all San Francisco residents have untreated, active HCV infection-likely a reflection of San Francisco's robust efforts to diagnose infection among high-risk groups and initiate curative treatment with as many people as possible. While plausible ranges of infections are wide, these findings indicate that while the overall number of people with anti-HCV antibodies may have increased slightly, the number of people with active HCV infection may have decreased slightly since 2015. This estimate improves upon the 2015 calculations by directly estimating the impact of curative treatment citywide and in subgroups. However, more research is needed to better understand the burden of HCV disease among other subgroups at high risk, such as Blacks/African Americans, people with a history of injection drug use (but not injecting drugs in the last 12 months), people who are currently or formerly incarcerated, and people who are currently or formerly unhoused.

BackgroundTo achieve elimination of hepatitis C virus (HCV) infection, limited resources can be best allocated through estimation of "care cascades" among groups disproportionately affected. In San Francisco and elsewhere, these groups include young (age ≤ 30 years) people who inject drugs (YPWID), men who have sex with men who inject drugs (MSM-IDU), and low-income trans women.MethodsWe developed cross-sectional HCV care cascades for YPWID, MSM-IDU, and trans women using diverse data sources. Population sizes were estimated using an inverse variance-weighted average of estimates from the peer-reviewed literature between 2013 and 2019. Proportions of past/current HCV infection, diagnosed infection, treatment initiation, and evidence of cure (sustained virologic response at 12 weeks posttreatment) were estimated from the literature using data from 7 programs and studies in San Francisco between 2015 and 2020.ResultsThe estimated number of YPWID in San Francisco was 3748; 58.4% had past/current HCV infection, of whom 66.4% were diagnosed with current infection, 9.1% had initiated treatment, and 50% had confirmed cure. The corresponding figures for the 8135 estimated MSM-IDU were: 29.4% with past/current HCV infection, 70.3% diagnosed with current infection, 28.4% initiated treatment, and 38.9% with confirmed cure. For the estimated 951 low-income trans women, 24.8% had past/current HCV infection, 68.9% were diagnosed with current infection, 56.5% initiated treatment, and 75.5% had confirmed cure.ConclusionsIn all 3 populations, diagnosis rates were relatively high; however, attention is needed to urgently increase treatment initiation in all groups, with a particular unmet need among YPWID.

Whether requiring Graduate Record Examinations (GRE) results for doctoral applicants affects the diversity of admitted cohorts remains uncertain. This study randomized applications to 2 population-health doctoral programs at the University of California San Francisco to assess whether masking reviewers to applicant GRE results differentially affects reviewers' scores for underrepresented minority (URM) applicants from 2018-2020. Applications with GRE results and those without were randomly assigned to reviewers to designate scores for each copy (1-10, 1 being best). URM was defined as self-identification as African American/Black, Filipino, Hmong, Vietnamese, Hispanic/Latinx, Native American/Alaska Native, or Native Hawaiian/Other Pacific Islander. We used linear mixed models with random effects for the applicant and fixed effects for each reviewer to evaluate the effect of masking the GRE results on the overall application score and whether this effect differed by URM status. Reviewer scores did not significantly differ for unmasked versus masked applications among non-URM applicants (β = 0.15; 95% CI: -0.03, 0.33) or URM applicants (β = 0.02, 95% CI: -0.49, 0.54). We did not find evidence that removing GREs differentially affected URM compared with non-URM students (β for interaction = -0.13, 95% CI: -0.55, 0.29). Within these doctoral programs, results indicate that GRE scores neither harm nor help URM applicants.

BackgroundPeople who inject drugs (PWID) are disproportionately affected by hepatitis C virus (HCV). Data tracking the engagement of PWID in the continuum of HCV care are needed to assess the reach, target the response, and gauge impact of HCV elimination efforts.MethodsWe analyzed data from the National HIV Behavioral Surveillance (NHBS) surveys of PWID recruited via respondent driven sampling (RDS) in San Francisco in 2018. We calculated the number and proportion who self-reported ever: (1) tested for HCV, (2) tested positive for HCV antibody, (3) diagnosed with HCV, (4) received HCV treatment, (5) and attained sustained viral response (SVR). To assess temporal changes, we compared 2018 estimates to those from the 2015 NHBS sample.ResultsOf 456 PWID interviewed in 2018, 88% had previously been tested for HCV, 63% tested antibody positive, and 50% were diagnosed with HCV infection. Of those diagnosed, 42% received treatment. Eighty-one percent of those who received treatment attained SVR. In 2015 a similar proportion of PWID were tested and received an HCV diagnosis, compared to 2018. However, HCV treatment was more prevalent in the 2018 sample (19% vs. 42%, P-value 0.01). Adjusted analysis of 2018 survey data showed having no health insurance (APR 1.6, P-value 0.01) and having no usual source of health care (APR 1.5, P-value 0.01) were significantly associated with untreated HCV prevalence.ConclusionWhile findings indicate an improvement in HCV treatment uptake among PWID in San Francisco, more than half of PWID diagnosed with HCV infection had not received HCV treatment in 2018. Policies and interventions to increase coverage are necessary, particularly among PWID who are uninsured and outside of regular care.

Housing status affects drug using behaviors, but less is known about the relationship between housing patterns and hepatitis C virus (HCV) infection. HCV-negative young people who inject drugs (PWID) were enrolled into a prospective cohort (2003-2019) with quarterly study visits. We used Cox regression to estimate the independent association of recent housing status (housed vs. unhoused, housing stability, and housing trajectory) on HCV incidence. Among 712 participants, 245 incident HCV infections occurred over 963.8 person-years (py) (cumulative incidence 24.4/100 py). An inverse relationship between time housed and HCV incidence was observed (always unhoused 45.0/100 py, 95% confidence interval (CI) 37.1, 54.5; variably housed 18.0/100 py, 95% CI 15.0, 21.3; and always housed 7.0/100 py, 95% CI 3.0, 17.3). In Cox regression models controlling for confounders, those unhoused versus housed at baseline had a 1.9-fold increased infection risk (95% CI 1.4, 2.6). Those always unhoused versus always housed had a 1.5 times greater risk of HCV (95% CI 1.0, 2.3), and those spending a portion of time in stable housing a lower risk (adjusted relative hazard 0.05, 95% CI 0.3, 0.9) with a similar trend for those being housed for less time. Young adult PWID experiencing both recent and chronic states of being unhoused are at elevated risk for HCV infection. Importantly for this group of PWID, our findings indicate that some frequency of residential housing significantly reduces HCV infection risk.

We used two national surveys (2010: N = 1597; 2013: N = 1057) of people who inject drugs (PWID) in past-month to assess the prevalence and population size of PWID with either safe or unsafe injection and sex behaviors, overall and by HIV status. In 2013, only 27.0% (vs. 32.3% in 2010) had safe injection and sex, 24.6% (vs. 23.3% in 2010) had unsafe injection and sex, 26.4% (vs. 26.5% in 2010) had only unsafe injection, and 22.0% (vs. 18.0% in 2010) had unsafe sex only. Among HIV-positive PWID in 2013, only 22.1% (~ 2200 persons) had safe injection and sex, 14.2% (~ 1400 persons) had unsafe injection and sex, 53.1% (~ 5200 persons) had unsafe injection, and 10.6% had unsafe sex (~ 1100 persons). Among HIV-negative PWID in 2013, only 27.5% (~ 22,200 persons) had safe injection and sex, 25.9% (~ 20,900 PWID) had unsafe injection and sex, 23.2% (~ 18,700 persons) had unsafe injection, and 23.3% (~ 18,800 persons) had unsafe sex. HIV-positive and -negative PWID in Iran continue to be at risk of HIV acquisition or transmission which calls for targeted preventions services.

OBJECTIVE:To understand the number of young adult people who inject drugs (PWID) with hepatitis C virus (HCV) infection accessing direct-acting antiviral (DAA) treatment and their barriers and facilitators to treatment uptake. METHODS:Using prospective cohort data from young adult PWID in San Francisco with newly identified HCV infection, we calculated the number who: (i) accepted referral to DAA therapy, (ii) initiated DAA therapy, (iii) completed DAA therapy, and (iv) achieved sustained virologic response (SVR) or cure. Behavioral survey data identified possible barriers and facilitators to DAA therapy. RESULTS:Of 60 young adult PWID with new HCV infection identified between February 2015 and January 2018, thirty accepted a referral to HCV care; five initiated and completed HCV treatment and achieved cure. Barriers to DAA uptake included fear of medical establishments, competing basic needs, and delaying care because they were feeling well. CONCLUSION:While few HCV-positive young adult PWID engaged in DAA therapy, all those who did achieved cure. Youth-tailored services that overcome the stigma and marginalization related to injection drug use are needed to improve treatment uptake.

Sharing of injection drug use paraphernalia is a dyadic process linked to the transmission of HIV and hepatitis C virus (HCV). Despite this, limited research exists identifying specific dyadic interpersonal factors driving injecting partners' engagement in needle/syringe and ancillary injecting equipment sharing among young adults. Using semi-structured in-depth interview data collected between 2014 and 2015 from twenty-seven people who inject drugs (PWID), we applied an inductive approach to identify key injection drug-related interpersonal factors and developed a conceptual model integrating the findings based on interdependence theory. Interactions between injecting partners resulted in varying levels of injecting-related trust, cooperation, intimacy, and power. These factors interacted to collectively influence the type and level of risk perceived and enacted by injecting partners. The relationship between these injecting-related interpersonal factors, on the one hand, and risk perception on the other was dynamic and fluctuated between actions that protect the self (person-centered) and those that protect the partnership (partnership-centered). These findings indicate that the interpersonal context exerts substantial influence that shapes risk perception in all types of injecting partnerships. Partnership-focused prevention strategies should consider the dynamics of trust, cooperation, intimacy, and power, in characterizing dyadic risk perceptions and in understanding risky injecting practices among PWID.

BackgroundHCV incidence is increasing in the US, notably among younger people who inject drugs (PWID). In a cohort of young adult (age

BackgroundTo date, research applying the Sexual Relationship Power Scale (SRPS) has been limited to sexual risk behaviors.ObjectiveWe measured levels of sexual relationship power and examined associations between sexual relationship power and injecting and sexual behaviors that place women at increased risk for blood borne infections.MethodsUsing data from a cross-sectional study of young women who inject drugs (WWID) in San Francisco, USA, logistic regression analysis identified independent associations between SRPS and subscale scores (relationship control [RC] and decision making dominance [DMD]) and injecting and sexual behaviors.ResultsOf the 68 young WWID, 24 (34%) reported receptive syringe sharing, 38 (56%) reused/shared a cooker to prepare drugs, and 25 (37%) injected someone else's drug residue during the three-months prior to enrollment. Most (60, 88%) reported condomless sex with main sex-partner, 8 (12%) reported transactional sex, and 36 (53%) had two or more recent sex partners. The median SRPS score was 2.98 (IQR: 2.65, 3.18), 3.23 (IQR: 3.23, 3.57) for RC and 2.40 (IQR: 2.20, 2.60) for DMD. No significant associations were detected between SRPS or DMD and injecting or sexual risk behaviors. After adjusting for gender and years injecting, for every one-point increase in RC, women had a 6.70 lower odds of recent condomless sex (95%CI: 0.92, 50.00, p = 0.06), and a 3.90 lower odds of recent transactional sex (95%CI: 1.22, 12.50, p = 0.02).ConclusionOur study findings suggest that some components of sexual relationship power may play a role in sexual risk, but not in injecting risk.

We mapped hot spots and estimated the numbers of people who use drugs (PWUD) and who inject drugs (PWID) in 12 regions of Tanzania. Primary (ie, current and past PWUD) and secondary (eg, police, service providers) key informants identified potential hot spots, which we visited to verify and count the number of PWUD and PWID present. Adjustments to counts and extrapolation to regional estimates were done by local experts through iterative rounds of discussion. Drug use, specifically cocaine and heroin, occurred in all regions. Tanga had the largest numbers of PWUD and PWID (5190 and 540, respectively), followed by Mwanza (3300 and 300, respectively). Findings highlight the need to strengthen awareness of drug use and develop prevention and harm reduction programs with broader reach in Tanzania. This exercise provides a foundation for understanding the extent and locations of drug use, a baseline for future size estimations, and a sampling frame for future research.

Background:The objective of this study was to assess differences in hepatitis C virus (HCV) incidence by sex in people who inject drugs (PWID), using a large international multicohort set of pooled biological and behavioral data from prospective observational studies of incident human immunodeficiency virus (HIV) and HCV infections in high-risk cohorts (the InC3 Collaborative). Methods:HCV infection date was estimated based on a hierarchy of successive serological (anti-HCV), virological (HCV RNA), and clinical (symptoms and/or liver function tests) data. We used a Cox proportional hazards model to calculate the crude and adjusted female to male (F:M) hazard ratio (HR) for HCV incidence using biological sex as the main exposure. Results:A total of 1868 PWID were observed over 3994 person-years of observation (PYO). Unadjusted F:M HR was 1.38 (95% confidence interval [CI], 1.15-1.65) and remained significant after adjusting for behavioral and demographic risk factors (1.39 [95% CI, 1.12-1.72]). Although syringe and equipment sharing were associated with the highest HCV incidence rate in women (41.62 and 36.83 PYO, respectively), we found no sex differences attributed to these risk factors. Conclusions:Our findings indicate that women who inject drugs may be at greater risk of HCV acquisition than men, independent of demographic characteristics and risk behaviors. Multiple factors, including biological (hormonal), social network, and differential access to prevention services, may contribute to increased HCV susceptibility in women who inject drugs.

BACKGROUND:Initiated in 2016, End Hep C SF is a comprehensive initiative to eliminate hepatitis C (HCV) infection in San Francisco. The introduction of direct-acting antivirals to treat and cure HCV provides an opportunity for elimination. To properly measure progress, an estimate of baseline HCV prevalence, and of the number of people in various subpopulations with active HCV infection, is required to target and measure the impact of interventions. Our analysis was designed to incorporate multiple relevant data sources and estimate HCV burden for the San Francisco population as a whole, including specific key populations at higher risk of infection. METHODS:Our estimates are based on triangulation of data found in case registries, medical records, observational studies, and published literature from 2010 through 2017. We examined subpopulations based on sex, age and/or HCV risk group. When multiple sources of data were available for subpopulation estimates, we calculated a weighted average using inverse variance weighting. Credible ranges (CRs) were derived from 95% confidence intervals of population size and prevalence estimates. RESULTS:We estimate that 21,758 residents of San Francisco are HCV seropositive (CR: 10,274-42,067), representing an overall seroprevalence of 2.5% (CR: 1.2%- 4.9%). Of these, 16,408 are estimated to be viremic (CR: 6,505-37,407), though this estimate includes treated cases; up to 12,257 of these (CR: 2,354-33,256) are people who are untreated and infectious. People who injected drugs in the last year represent 67.9% of viremic HCV infections. CONCLUSIONS:We estimated approximately 7,400 (51%) more HCV seropositive cases than are included in San Francisco's HCV surveillance case registry. Our estimate provides a useful baseline against which the impact of End Hep C SF can be measured.

BackgroundPeople who inject drugs with sexual partners or close friends have high rates of syringe/ancillary equipment sharing and HIV and hepatitis C virus (HCV) infection. Although evidence suggests that interpersonal factors underlie these higher risk profiles, there is no quantitative measure of how interpersonal factors operate within injecting relationships. We aimed to develop and validate a quantitative scale to assess levels of injecting drug-related interpersonal factors associated with risky injecting behaviours within injecting partnerships.MethodsWe conducted qualitative interviews with 45 people who inject drugs (PWID) who reported having injecting partners to inform item development, and tested these items in a quantitative study of 140 PWID from San Francisco, USA, to assess internal reliability (Cronbach's alpha) and validity (convergent, and discriminant validity).ResultsWith results from the qualitative interview data, we developed the Interpersonal Dynamics in Injecting Partnerships (IDIP) scale with 54 final items for 5 subscales of injecting-related interpersonal factors. Exploratory factor analysis revealed 5 factors ("trust", "power", "risk perception", "intimacy", and "cooperation") with eigenvalues of 14.32, 6.18, 3.55, 2.46, and 2.14, explaining 57% of the variance, and indicating good internal reliability (alpha: 0.92-0.68). Strong convergent validity was observed in bivariate logistic regression models where higher levels of trust, intimacy, and cooperation within partnerships were positively associated with partners sharing needles and injecting equipment, whereas higher levels of power and risk perception were negatively associated with partners sharing needles and injecting equipment.ConclusionsThese findings offer strong evidence that the IDIP scale provides a psychometrically sound measure of injecting drug-related interpersonal dynamics. This measurement tool has the potential to facilitate additional investigations into the individual and collective impact of trust, intimacy, power, cooperation, and risk perception on injection drug using behaviours and engagement in HIV and HCV testing and treatment among PWID in a variety of settings.

BackgroundWe determined temporal trends (1985-2011) in hepatitis C virus (HCV) incidence and associated behavioral exposures for people who inject drugs (PWID) from the United States (Boston, Baltimore, and San Francisco), Canada (Montreal), the Netherlands (Amsterdam), and Australia (Sydney and Melbourne).MethodsUsing population-based cohort data from HCV-negative PWID, we calculated overall and within-city HCV incidence trends, HCV rates by study enrollment period (1985-2011), and temporal trends in exposure behaviors. Poisson regression models estimated trends in HCV incidence over calendar-time. Survival models identified risk factors for HCV incidence across cities and estimated independent effects of city and calendar period on HCV infection risk.ResultsAmong 1391 initially HCV-negative participants followed prospectively (1644.5 person-years of observation [PYO]), 371 HCV incident infections resulted in an overall incidence of 22.6 per 100 PYO (95% confidence interval [CI], 20.4-25.0). Incidence was highest and remained elevated in Baltimore (32.6/100 PYO), San Francisco (24.7/100 PYO), and Montreal (23.5/100 PYO), lowest in Melbourne and Amsterdam (7.5/100 PYO and 13.1/100 PYO, respectively), and moderate (21.4/100 PYO) in Sydney. Higher rates of syringe and equipment sharing and lower prevalence of opioid agonist therapy were associated with HCV incidence in cities with the highest incidence. Risk for infection dropped by 18% for every 3-year increase in calendar-time (adjusted hazard ratio, 0.8 [95% CI, .8-.9]) in the multivariable model.ConclusionsDifferences in prevention strategies and injecting contexts may explain the ongoing high HCV incidence in these North American cities and emphasize the need for scale-up of opioid agonist therapy and increased coverage of needle and syringe programs in North America.

BackgroundStudies have shown intimate injection partners engage in higher rates of syringe and injecting equipment sharing. We examined the drug use context and development of injection drug use behaviors within intimate injection partnerships.MethodsIn-depth interviews (n=18) were conducted with both members of nine injecting partnerships in Sydney, Australia. Content analysis identified key domains related to the reasons for injecting with a primary injection partner and development of drug injection patterns.Main findingsMost partnerships (n=5) were also sexual; three were blood-relatives and one a friend dyad. The main drug injected was heroin (66%) with high rates of recent sharing behaviors (88%) reported within dyads. Injecting within a primary injection partnership provided perceived protection against overdose events, helped reduce stress, increased control over when, where, and how drugs were used, and promoted the development of an injecting pattern where responsibilities could be shared. Unique to injecting within primary injection partnerships was the social connection and companionship resulted in a feeling of fulfillment while also blinding one from recognizing risky behavior.ConclusionsFindings illuminated the tension between protection and risks within primary injection partnerships. Primary injection partnerships provide a potential platform to expand risk reduction strategies.

IntroductionYoung injection drug users (IDU, under age 30) often inject with other IDU, creating an environment for risk of blood-borne disease transmission through sharing of needles and drug preparation equipment. Epidemiologic studies rely on self reported injection behavior data for measures of transmission risk, therefore we sought to quantify the degree of concordance of reported injecting risk behaviors between injecting dyads.MethodsFrom May, 2006 through 2013 we enrolled 72 injecting dyads in San Francisco, California, who were hepatitis C virus (HCV) RNA discordant. Each partnership was followed prospectively for up to six months. Monthly interviews from each partner were date-matched and responses to relationship characteristics and risk behavior questions were compared. Concordance of reporting was estimated with the concordance correlation coefficient for longitudinal data (CCC) and the prevalence adjusted bias adjusted kappa (PABAK).ResultsParticipants had a median age of 26 (IQR: 23, 28) years and median years injecting of 7.0 (IQR: 3.0, 10.6). Thirty-eight percent of the injecting dyads were also sexual partners. Concordance levels were highest for partnership characteristics, such as length of acquaintance, number of days cohabitating, and sexual intercourse in the past month (CCC=0.95; 0.82, and 0.90, respectively). Shared injection risk behaviors such as injecting with the HCV+ partner's previously used syringe and using contaminated injection preparation equipment had slight to fair agreement (CCC=0.22; 0.23; PABAK=0.43, 0.36, respectively).ConclusionsConcordance levels ranged from low to high. Potential sources of measurement error for low agreement items include recall and social-desirability biases and question interpretation.

BackgroundFemale injection drug users (IDUs) may report differences in injection behaviours that put them at greater risk for hepatitis C virus (HCV). Few studies have examined these in association with HCV incidence.MethodsLongitudinal data from a cohort of 417 HCV-uninfected IDU aged 30 or younger were analysed. Cox proportional hazards was used to model female sex as a predictor of new HCV infection. General estimating equation (GEE) analysis was used to model female sex as a predictor of HCV-associated risk behaviour prospectively.ResultsWomen were significantly more likely than men to become infected with HCV during study follow-up (HR 1.4, p

The hepatitis C virus (HCV) virus epidemic is ongoing in the United States and globally. Incidence rates remain high, especially in young adult injection drug users. New outbreaks of HCV in the United States among young adults, in predominantly suburban and rural areas, have emerged and may be fueling an increase in HCV. This paper discusses some key HCV prevention strategies that to date have not been widely researched or implemented, and wherein future HCV prevention efforts may be focused: (1) reducing sharing of drug preparation equipment; (2) HCV screening, and testing and counseling; (3) risk reduction within injecting relationships; (4) injection cessation and "breaks"; (5) scaled-up needle/syringe distribution, HCV treatment, and vaccines, according to suggestions from mathematical models; and (6) "combination prevention." With ongoing and expanding transmission of HCV, there is little doubt that there is a need for implementing what is in the prevention "toolbox" as well as adding to it. Strong advocacy and resources are needed to overcome challenges to providing the multiple and comprehensive programs that could reduce HCV transmission and associated burden of disease worldwide in people who inject drugs.