Barriers to receiving hepatitis C treatment for people who inject drugs: Myths and evidence

Background: Alcohol consumption, current injecting drug use, and pre-existing mental illness have been identified as 3 of the main reasons for excluding patients from treatment for hepatitis C. Objectives: We reviewed the literature to obtain an evidence base for these common exclusion criteria. Materials and Methods: We reviewed original research and meta-analyses investigating the effects of alcohol consumption, current injecting drug use, and pre-existing mental illness. Results: We identified 66 study reports relevant to the review, but found only limited evidence to support withholding of treatment on the basis of the 3 previously mentioned exclusion criteria. Conclusions: Currently, there is a lack of evidence for many of the barriers faced by patients in availing treatment for hepatitis C. Adherence to treatment routine was found to be a better predictor of sustained virological response than injecting drug or alcohol consumption during treatment period or the presence of a pre-existing mental disorder. Although several challenges remain, we need to ensure that treatment decisions are based on the best available evidence and the treatment is performed appropriately on a case-by-case basis. © 2011 Kowsar M.P.Co. All rights reserved

Eradication of hepatitis C infection: the importance of targeting people who inject drugs

Hepatitis C virus (HCV) affects ~170 million people worldwide and causes significant morbidity and mortality.1 In high-income countries, people who inject drugs (PWID) are at greatest risk of HCV infection.2 Until recently HCV eradication seemed unlikely, but recent advances in HCV treatment and improved understanding of the effectiveness of harm-reduction intervention effectiveness give reason for optimism. Current HCV treatments can cure ~75% of patients and new drugs will further improve effectiveness (over 90% cure) and improve tolerability.3 If HCV treatment can be delivered effectively to those at highest risk of onward transmission, significant reductions in future HCV cases are possible. The feasibility of disease eradication must be assessed on both scientific criteria (e.g., epidemiological susceptibility, effective and practical intervention available, and demonstrated feasibility of elimination) and political criteria (e.g., burden of disease, cost of intervention).4 With effective, curative treatment now available, HCV meets these criteria

Self-reported recent testing and diagnosis for sexually transmitted infections among regular ecstasy users in Australia, 2011–2012

Background: Previous studies suggest that people who consume alcohol and drugs are at increased risk of sexually transmitted infections (STI). We examined the prevalence and predictors of self-reported STI testing and diagnosis among self-reported regular ecstasy users (REU). Methods: Nine hundred and fifty-five REUs from the 2011 and 2012 Ecstasy and Related Drugs Reporting System were included in the analysis. Bivariate and multivariate Poisson regression were used to identify predictors of recent STI testing, and logistic regression was used to identify predictors of recent STI diagnosis. Results: Forty-four per cent of REUs reported having a recent STI test, and 5% reported a recent diagnosis. Of the 421 REUs who reported a recent test, 10% reported a recent STI diagnosis. In multivariate analysis, REUs were more likely to report a recent STI test if they were female versus male [risk ratio (RR) = 1.56; 95% confidence interval (CI) = 1.36-1.80], aged 25–29 years versus 16–19 years (RR = 1.34; 95% CI = 1.05-1.72), or reported ≥2 casual sex partners versus no casual partners (RR = 1.48; 95% CI = 1.01–2.14). REUs reporting cannabis use in the past six months were 0.78 times less likely to report a recent STI test (95% CI = 0.66-0.94).There were no significant predictors associated with STI diagnosis. Conclusion: Encouragingly, REUs who reported having multiple casual partners in the past six months were more likely to report a recent test. However, younger REUs aged 16–19 years were least likely to test, suggesting health promotion needs to be directed to this age group. Further research is required to explain the lower testing among cannabis users

The impact of injecting networks on hepatitis C transmission and treatment in people who inject drugs

With the development of new highly efficacious direct acting antiviral treatments (DAAs) for hepatitis C (HCV), the concept of treatment as prevention is gaining credence. To date the majority of mathematical models assume perfect mixing with injectors having equal contact with all other injectors. This paper explores how using a networks based approach to treat people who inject drugs (PWID) with DAAs affects HCV prevalence. Method: Using observational data we parameterized an Exponential Random Graph Model containing 524 nodes. We simulated transmission of HCV through this network using a discrete time, stochastic transmission model. The effect of five treatment strategies on the prevalence of HCV was investigated; two of these strategies were 1) treat randomly selected nodes and 2) “treat your friends” where an individual is chosen at random for treatment and all their infected neighbours are treated. Results: As treatment coverage increases, HCV prevalence at 10 years reduces for both the high efficacy and low efficacy treatment. Within each set of parameters, the “treat your friends” strategy performed better than the random strategy being most marked for higher efficacy treatment. For example over 10 years of treating 25 per 1000 PWID, the prevalence drops from 50% to 40% for the random strategy, and to 33% for the “treat your friends” strategy (6.5% difference, 95% CI 5.1 – 8.1%). Discussion: “Treat your friends” is a feasible means of utilising network strategies to improve treatment efficiency. In an era of highly efficacious and highly tolerable treatment such an approach will benefit not just the individual but the community more broadly by reducing the prevalence of HCV amongst PWID

Perfectly matched layers in transmission lines

The field distribution at the ports of the transmission line structure is computed by applying Maxwell's equations to the structure and solving an eigenvalue problem. The high dimensional sparse system matrix is complex in the presence of losses and Perfectly Matched Layer. A method is presented which preserves sparseness and delivers only the small number of interesting modes out with the smallest attenuation. The modes are found solving a sequence of eigenvalue problems of modified matrices with the aid of the invert mode of the Arnoldi iteration using shifts. A new strategy is described which allows the application of the method, first developed for microwave structures, to optoelectronic devices

Description of social contacts among student cases of pandemic influenza during the containment phase, Melbourne, Australia, 2009

Introduction: Students comprised the majority of early cases of influenza A(H1N1)pdm09 in Melbourne, Australia. Students and school settings were targeted for public health interventions following the emergence of pH1N1. This study was conducted to describe changes in social contacts among the earliest confirmed student cases of pH1N1 in Melbourne, Australia, to inform future pandemic control policy and explore transmission model assumptions. Methods: A retrospective cross-sectional behavioural study of student cases with laboratory-confirmed pH1N1 between 28 April and 3 June 2009 was conducted in 2009. Demographics, symptom onset dates and detailed information on regular and additional extracurricular activities were collected. Summary measures for activities were calculated, including median group size and median number of close contacts and attendance during the students' exposure and infectious periods or during school closures. A multivariable model was used to assess associations between rates of participation in extracurricular activities and both school closures and students' infectious periods. Results: Among 162 eligible cases, 99 students participated. Students reported social contact in both curricular and extra-curricular activities. Group size and total number of close contacts varied. While participation in activities decreased during the students' infectious periods and during school closures, social contact was common during periods when isolation was advised and during school closures. Discussion: This study demonstrates the potential central role of young people in pandemic disease transmission given the level of non-adherence to prevention and control measures. These finding have public health implications for both informing modelling estimates of future pandemics and targeting prevention and control strategies to young people

Hepatitis C transmission and treatment as prevention - The role of the injecting network

Background: The hepatitis C virus (HCV) epidemic is a major health issue; in most developed countries it is driven by people who inject drugs (PWID). Injecting networks powerfully influence HCV transmission. In this paper we provide an overview of 10 years of research into injecting networks and HCV, culminating in a network-based approach to provision of direct-acting antiviral therapy. Methods: Between 2005 and 2010 we followed a cohort of 413 PWID, measuring HCV incidence, prevalence and injecting risk, including network-related factors. We developed an individual-based HCV transmission model, using it to simulate the spread of HCV through the empirical social network of PWID. In addition, we created an empirically grounded network model of injecting relationships using exponential random graph models (ERGMs), allowing simulation of realistic networks for investigating HCV treatment and intervention strategies. Our empirical work and modelling underpins the TAP Study, which is examining the feasibility of community-based treatment of PWID with DAAs. Results: We observed incidence rates of HCV primary infection and reinfection of 12.8 per 100 person-years (PY) (95%CI: 7.7-20.0) and 28.8 per 100 PY (95%CI: 15.0-55.4), respectively, and determined that HCV transmission clusters correlated with reported injecting relationships. Transmission modelling showed that the empirical network provided some protective effect, slowing HCV transmission compared to a fully connected, homogenous PWID population. Our ERGMs revealed that treating PWID and all their contacts was the most effective strategy and targeting treatment to infected PWID with the most contacts the least effective. Conclusion: Networks-based approaches greatly increase understanding of HCV transmission and will inform the implementation of treatment as prevention using DAAs

稲垣足穂『少年愛の美学』の読書論的研究 --念者としての語り--

千葉大学大学院人文社会科学研究科研究プロジェクト報告書第144集 『パフォーマンスの民族誌的研究』橋本裕之