Modeling Combination Hepatitis C Virus Treatment and Prevention Strategies in a Network of People Who Inject Drugs in the United States.

BACKGROUND: Hepatitis C virus (HCV) treatment as prevention (TasP) strategies can contribute to HCV microelimination, yet complimentary interventions such as opioid agonist therapies (OAT) with methadone or buprenorphine and syringe services programs (SSPs) may improve the prevention impact. This modeling study estimates the impact of scaling up the combination of OAT and SSPs with HCV TasP in a network of people who inject drugs (PWID) in the United States. METHODS: Using empirical data from Hartford, Connecticut, we deployed a stochastic block model to simulate an injection network of 1574 PWID. We used a susceptible-infected model for HCV and human immunodeficiency virus to evaluate the effectiveness of several HCV TasP strategies, including in combination with OAT and SSP scale-up, over 20 years. RESULTS: At the highest HCV prevalence (75%), when OAT coverage is increased from 10% to 40%, combined with HCV treatment of 10% per year and SSP scale up to 40%, the time to achieve microelimination is reduced from 18.4 to 11.6 years. At the current HCV prevalence (60%), HCV TasP strategies as low as 10% coverage per year may achieve HCV microelimination within 10 years, with minimal impact from additional OAT scale-up. Strategies based on mass initial HCV treatment (50 per 100 PWID the first year followed by 5 per 100 PWID thereafter) were most effective in settings with HCV prevalence of 60% or lower. CONCLUSIONS: Scale-up of HCV TasP is the most effective strategy for microelimination of HCV. OAT scale-up, however, scale-up may be synergistic toward achieving microelimination goals when HCV prevalence exceeds 60% and when HCV treatment coverage is 10 per 100 PWID per year or lower.

Estimating HIV and HCV prevalence among people who inject drugs in 5 Ukrainian cities using stratification-based respondent driven and random sampling.

BACKGROUND: Ukraine, a country of 45.5 million people, has one of the most volatile HIV and HCV epidemics in the world. In this paper, we estimate the prevalence of HIV and HCV among PWID in five Ukrainian cities. METHODS: A cross-sectional study was conducted in 2014-2015, based on stratified hybrid sampling with random and respondent driven sampling in five cities: Kyiv, Odesa, Mykolaiv, Dnipro and Lviv. Using data on HIV and HCV antibody testing from 1613 respondents, we evaluate selection bias in the sampling methods by analyzing spatial and network patterns of sampling processes. We develop and apply inverse probability weights in order to estimate the HIV and HCV prevalence in each city, as well as in the overall sample. FINDINGS: The aggregate HIV prevalence for the five cities is 35.1% (95% CI: 29.5%-38.5%) but this varied considerably by city: in Kyiv the HIV prevalence is 26.6% (95% CI: 20.3.8%-33.4%), in Odesa - 38.2% (95% CI: 29.8% and 47.1%), in Mykolaiv - 42.0% (95% CI: 34.3%-49.2%), in Dnipro - 58.8% (95% CI: 52.2%-65.8%), and in Lviv 24.6% (95% CI: 18.8%-30.8%). The aggregate HCV prevalence estimate for the five cities is 58.6% (95% CI: 54.9%-61.7%). The highest HCV prevalence is estimated in Kyiv - 84.8% (95% CI: 78.5%-90.1%). HCV prevalence in Odesa is the lowest and estimated to be 36.5% (95% CI: 29.5%-45.1%), in Mykolaiv - 49.1% (95% CI: 41.5%-57.0%), in Dnipro - 56.1% (95% CI: 50.3%-63.4%) and in Lviv 38.5% (95% CI: 31.8%-45.0%). CONCLUSIONS: Monitoring behavioral and health outcomes of PWID on a regular basis is necessary for determining prevention and treatment priorities for HIV and HCV infections in Ukraine and elsewhere. The heterogeneity of the local epidemics provides insights into the best prevention and treatment strategies to be deployed in low-resource settings.

Assessment of barrier severity and willingness to enter opioid agonist treatment among people who inject drugs in Ukraine.

BACKGROUND: Opioid agonist therapies (OAT) in Ukraine were first introduced in 2004 not as addiction treatment, but for HIV prevention. Numerous obstacles have thwarted OAT scale-up, including individual constraints and structural barriers. METHODS: A cross-sectional survey of 1613 opioid dependent people who inject drugs (PWID) were recruited in 2014-2015 using stratified sampling in Kyiv, Odesa, Mykolayiv, Dnipro and Lviv. Analysis was restricted to a subset of 811 PWID who never received OAT. Barriers to OAT were assessed based on reasons why study participants were reluctant to enroll into OAT. A Rasch model from the Item Response Theory was applied to 24 potential barriers, used to score their severity and estimate a latent composite measure for each person's willingness and ability to participate in OAT. RESULTS: The Rasch model confirmed the cumulative nature of barriers with concerns over treatment efficacy, safety and tolerability being more prevalent than barriers related to logistical constraints, opportunity costs and social stigma. If barriers related to treatment perception and logistics were eliminated, the average barrier number would decrease from 10 to 2.2. Participants were more likely to have a higher resistance to OAT entry if they experienced fewer overdoses, did not attain higher education, were not previously incarcerated and if their peers did not have a higher level of resistance to OAT. CONCLUSIONS: Understanding the interdependence of various barriers and attitudes toward OAT can improve the rate of OAT expansion and ameliorate entry into substance abuse treatment programs in Ukraine.