How to eliminate HCV in people who inject drugs in the USA

Modeling hepatitis C micro-elimination among people who inject drugs with direct-acting antivirals in metropolitan Chicago

Hepatitis C virus (HCV) infection is a leading cause of chronic liver disease and mortality worldwide. Direct-acting antiviral (DAA) therapy leads to high cure rates. However, persons who inject drugs (PWID) are at risk for reinfection after cure and may require multiple DAA treatments to reach the World Health Organization's (WHO) goal of HCV elimination by 2030. Using an agent-based model (ABM) that accounts for the complex interplay of demographic factors, risk behaviors, social networks, and geographic location for HCV transmission among PWID, we examined the combination(s) of DAA enrollment (2.5%, 5%, 7.5%, 10%), adherence (60%, 70%, 80%, 90%) and frequency of DAA treatment courses needed to achieve the WHO's goal of reducing incident chronic infections by 90% by 2030 among a large population of PWID from Chicago, IL and surrounding suburbs. We also estimated the economic DAA costs associated with each scenario. Our results indicate that a DAA treatment rate of >7.5% per year with 90% adherence results in 75% of enrolled PWID requiring only a single DAA course; however 19% would require 2 courses, 5%, 3 courses and <2%, 4 courses, with an overall DAA cost of $325 million to achieve the WHO goal in metropolitan Chicago. We estimate a 28% increase in the overall DAA cost under low adherence (70%) compared to high adherence (90%). Our modeling results have important public health implications for HCV elimination among U.S. PWID. Using a range of feasible treatment enrollment and adherence rates, we report robust findings supporting the need to address re-exposure and reinfection among PWID to reduce HCV incidence.

People who inject drugs in metropolitan Chicago: A meta-analysis of data from 1997-2017 to inform interventions and computational modeling toward hepatitis C microelimination

Progress toward hepatitis C virus (HCV) elimination in the United States is not on track to meet targets set by the World Health Organization, as the opioid crisis continues to drive both injection drug use and increasing HCV incidence. A pragmatic approach to achieving this is using a microelimination approach of focusing on high-risk populations such as people who inject drugs (PWID). Computational models are useful in understanding the complex interplay of individual, social, and structural level factors that might alter HCV incidence, prevalence, transmission, and treatment uptake to achieve HCV microelimination. However, these models need to be informed with realistic sociodemographic, risk behavior and network estimates on PWID. We conducted a meta-analysis of research studies spanning 20 years of research and interventions with PWID in metropolitan Chicago to produce parameters for a synthetic population for realistic computational models (e.g., agent-based models). We then fit an exponential random graph model (ERGM) using the network estimates from the meta-analysis in order to develop the network component of the synthetic population.

Changing Urban-Rural Disparities in the Utilization of Direct-Acting Antiviral Agents for Hepatitis C in U.S. Medicare Patients, 2014-2017

INTRODUCTION

The advent of direct-acting antiviral agents for treating hepatitis C virus infection has made hepatitis C virus elimination possible. Rural patients with hepatitis C virus infection may be less likely to access direct-acting antiviral agents, but the real-world evidence is scarce on urban-rural disparities in direct-acting antiviral agent utilization.

METHODS

This retrospective cohort study was conducted in 2019-2020 using Medicare data to examine urban-rural disparities in direct-acting antiviral agent utilization among newly diagnosed patients with hepatitis C virus infection in 2014-2016. Direct-acting antiviral agent use was defined as filling ≥1 prescription for direct-acting antiviral agents during 2014-2017, and patient's urban-rural status was classified on the basis of their ZIP code of residence. This study evaluated the associations between multilevel factors and direct-acting antiviral agent use with a focus on urban-rural disparities. It also assessed changes over time in urban-rural disparities in direct-acting antiviral agent utilization using multivariable cause-specific Cox regression analyses with time-varying hazard ratios.

RESULTS

Among 204,018 new patients with hepatitis C virus infection, about 30% received direct-acting antiviral agents during 2014-2017. Cumulative direct-acting antiviral agent use gradually increased over time in both urban and rural patients. However, the increase was greater in urban patients than in rural patients. In the first year of follow-up, rural patients had a similar rate of receiving direct-acting antiviral agents (adjusted hazard ratio=1.03, 95% CI=1.00, 1.07), but they were less likely to use direct-acting antiviral agents in later years than urban patients (adjusted hazard ratio=0.85, 95% CI=0.81, 0.90 in the second year, adjusted hazard ratio=0.82, 95% CI=0.76, 0.89 in the third year, and adjusted hazard ratio=0.76, 95% CI=0.64, 0.90 in the fourth year of follow-up).

CONCLUSIONS

This study reveals important gaps in hepatitis C virus treatment and suggests increasing urban-rural disparities in direct-acting antiviral agent utilization. Enhancing direct-acting antiviral agent uptake in rural populations with hepatitis C virus infection will help reduce hepatitis C virus‒related health disparities and reach the national goal of eliminating hepatitis C virus infection.

MULTI-OBJECTIVE MODEL EXPLORATION OF HEPATITIS C ELIMINATION IN AN AGENT-BASED MODEL OF PEOPLE WHO INJECT DRUGS

Hepatitis C (HCV) is a leading cause of chronic liver disease and mortality worldwide and persons who inject drugs (PWID) are at the highest risk for acquiring and transmitting HCV infection. We developed an agent-based model (ABM) to identify and optimize direct-acting antiviral (DAA) therapy scale-up and treatment strategies for achieving the World Health Organization (WHO) goals of HCV elimination by the year 2030. While DAA is highly efficacious, it is also expensive, and therefore intervention strategies should balance the goals of elimination and the cost of the intervention. Here we present and compare two methods for finding PWID treatment enrollment strategies by conducting a standard model parameter sweep and compare the results to an evolutionary multi-objective optimization algorithm. The evolutionary approach provides a pareto-optimal set of solutions that minimizes treatment costs and incidence rates.

Modeling of patient virus titers suggests that availability of a vaccine could reduce hepatitis C virus transmission among injecting drug users

The major route of hepatitis C virus (HCV) transmission in the United States is injection drug use. We hypothesized that if an HCV vaccine were available, vaccination could affect HCV transmission among people who inject drugs by reducing HCV titers after viral exposure without necessarily achieving sterilizing immunity. To investigate this possibility, we developed a mathematical model to determine transmission probabilities relative to the HCV RNA titers of needle/syringe-sharing donors. We simulated sharing of two types of syringes fitted with needles that retain either large or small amounts of fluid after expulsion. Using previously published viral kinetics data from both naïve subjects infected with HCV and reinfected individuals who had previously cleared an HCV infection, we estimated transmission risk between pairs of serodiscordant injecting drug users, accounting for syringe type, rinsing, and sharing frequency. We calculated that the risk of HCV transmission through syringe sharing increased ~10-fold as viral titers (log₁₀ IU/ml) increased ~25-fold. Cumulative analyses showed that, assuming sharing episodes every 7 days, the mean transmission risk over the first 6 months was >90% between two people sharing syringes when one had an HCV RNA titer >5 log₁₀ IU/ml. For those with preexisting immunity that rapidly controlled HCV, the cumulative risk decreased to 1 to 25% depending on HCV titer and syringe type. Our modeling approach demonstrates that, even with transient viral replication after exposure during injection drug use, HCV transmission among people sharing syringes could be reduced through vaccination if an HCV vaccine were available.

Modeling indicates efficient vaccine-based interventions for the elimination of hepatitis C virus among persons who inject drugs in metropolitan Chicago

BACKGROUND AND AIMS

Persons who inject drugs (PWID) are at highest risk for acquiring and transmitting hepatitis C (HCV) infection. The recent availability of oral direct-acting antiviral (DAA) therapy with reported cure rates >90% can prevent HCV transmission, making HCV elimination an attainable goal among PWID. The World Health Organization (WHO) recently proposed a 90% reduction in HCV incidence as a key objective. However, given barriers to the use of DAAs in PWID, including cost, restricted access to DAAs, and risk of reinfection, combination strategies including the availability of effective vaccines are needed to eradicate HCV as a public health threat. This study aims to model the cost and efficacy of a dual modality approach using HCV vaccines combined with DAAs to reduce HCV incidence by 90% and prevalence by 50% in PWID populations.

METHODS

We developed a mathematical model that represents the HCV epidemic among PWID and calibrated it to empirical data from metropolitan Chicago, Illinois. Four medical interventions were considered: vaccination of HCV naive PWID, DAA treatment, DAA treatment followed by vaccination, and, a combination of vaccination and DAA treatment.

RESULTS

The combination of vaccination and DAAs is the lowest cost-expensive intervention for achieving the WHO target of 90% incidence reduction. The use of DAAs without a vaccine is much less cost-effective with the additional risk of reinfection after treatment. Vaccination of naïve PWID alone, even when scaled-up to all reachable PWID, cannot achieve 90% reduction of incidence in high-prevalence populations due to infections occurring before vaccination. Similarly, the lowest cost-expensive way to halve prevalence in 15 years is through the combination of vaccination and DAAs.

CONCLUSIONS

The modeling results underscore the importance of developing an effective HCV vaccine and augmenting DAAs with vaccines in HCV intervention strategies in order to achieve efficient reductions in incidence and prevalence.

Federal Response to the Opioid Crisis

PURPOSE OF REVIEW

In light of the current crisis in opioid involved overdose deaths, the federal Department of Health and Human Services operating divisions are working together to implement a data-driven, research-based strategy to reduce opioid misuse and its consequences.

RECENT FINDINGS

The strategy has five elements: (1) strengthening public health data collection and reporting; (2) advancing the practice of pain management; (3) improving access to addiction prevention, treatment, and recovery support services; (4) increasing availability of overdose-reversing drugs; and (5) supporting cutting-edge research in treatment of pain, opioid use disorder, and associated conditions. The Department of Health and Human Services has developed a concerted, coordinated evidence-based effort across department divisions to reduce opioid misuse, prevalence of opioid use disorder, and reduce deaths due to opioid use.