Review article: treatment as prevention – targeting people who inject drugs as a pathway towards hepatitis C eradication

Abstract

Summary Background Hepatitis C virus (HCV) is a leading cause of chronic liver disease worldwide. HCV predominates in people who inject drugs; a group in whom anti‐viral therapy has previously been withheld on the basis of chaotic lifestyles and associated risks of reinfection. New research has emerged which suggests that by specifically targeting HCV‐infected people who inject drugs for treatment, the pool of HCV would deplete, thus reducing overall transmission and eventually leading to HCV eradication. Aim To outline the requirements for HCV eradication and review the evidence that this is achievable. Methods Expert review of the literature. Results The achievement of HCV eradication using ‘treatment as prevention’ is supported by numerous epidemiological modelling studies employing a variety of models in several contexts including people who inject drugs, men who have sex with men and prisoners. More recent studies also incorporate the newer, more efficacious direct‐acting anti‐viral drugs. These drugs have been shown to be safe and effective in people who inject drugs in clinical trials. There is no empirical evidence of the impact of treatment as prevention strategies on population prevalence. Conclusions This review highlights the efforts to control HCV and evaluates the possibilities of achieving eradication of HCV. Currently, the technologies required to achieve HCV eradication exist, but the infrastructure to deliver them is not generally available or of insufficient scale outside of specific areas. Such areas are yet to demonstrate that elimination is possible, but results of studies in these areas are awaited. Such a demonstration would be proof of principle for eradication. Although we are aspiring towards HCV eradication, elimination is the more realistic prospect.

HCV point‐of‐care screening programme and treatment options for people who use drugs in a metropolitan area of Southern Italy

“…Also the shorter follow‐up period (6 months) in our study versus 18 months and beyond in other studies could also explain this discrepancy . However, there is now extensive evidence that PWUD affected by HCV can be successfully targeted and treated …”

Systematic review with meta‐analysis: effectiveness and tolerability of interferon‐free direct‐acting antiviral regimens for chronic hepatitis C genotype 1 in routine clinical practice in Asia

“…The above results have important implications for Asian countries where HCV‐infected patients are ageing and can have more comorbidities such as chronic kidney disease, and these historically difficult‐to‐treat populations should be considered for treatment, except individuals with limited life expectancy due to non‐liver‐related comorbidities. Furthermore, similar to the treatment of acute hepatitis C and persons who inject recreational drugs, treating HCV patients on haemodialysis will reduce the risk of transmission of the virus to other high‐risk individuals and can contribute to the eradication of HCV …”

The Micro-Elimination Approach to Eliminating Hepatitis C: Strategic and Operational Considerations

“…[15][16][17][18][19] Micro-elimination approaches in populations at high risk of transmitting HCV can potentially contribute to "treatment as prevention." 20 The concept of treatment as prevention is to successfully treat an HCV-infected person who is at a risk of passing the virus on to others and eliminate the possibility of further transmission, thereby achieving "prevention." While there is not yet a real-world demonstration of the potency of treatment as prevention, modeling indicates that carrying out this strategy on a sufficiently large scale accelerates progression to population elimination, with especially notable gains seen when PWID are the focus in HCV epidemics driven by injecting drug use.…”

“…21,22 In other words, if a large proportion of HCVinfected PWID in a specific geographic area undergo successful treatment and achieve SVR, this will result in a sharp drop in the number of HCV-infected people who have the potential to transmit the disease to others with whom they share injecting equipment. 20 The aim of treatment as prevention is to successfully treat enough people to reach a threshold where new infections are greatly reduced. Because of the potential to prevent further infections, many of which would incur the high costs of treating end-stage liver disease, models suggest that high levels of treatment combined with other preventive measures may prove cost-effective, especially if indirect costs such as loss of earnings due to disability are considered.…”