Effective Interventions Unit - Hepatitis C: Risks and prevention strategies in injecting drug users

Introduction

This review draws on key findings from recent research and surveillance activities that examine Hepatitis C among injecting drug users. It is aimed at anyone involved in planning, commissioning, developing and delivering interventions to prevent Hepatitis C.
Information on Hepatitis C, routes of transmission and the scale of the problem in Scotland are included in the review. Finally, am overview of prevention strategies is presented.

Information on the hepatitis C virus and routes of transmission

Hepatitis C is a slow progressing disease of the liver spread by blood and blood stained body fluids.
There are a number of ways in which the hepatitis C virus can be spread. These include injecting drug use, transfusion of contaminated blood and blood products, tattooing, electrolysis and body piercing, needlestick injury, perinatal transmission (from mother to baby) and sexual transmission.
Injecting drug use is the most common risk factor for the hepatitis C virus (HCV). Transmission is linked to the sharing of injecting equipment.
Approximately 80% of those infected develop chronic hepatitis C, but may be without symptoms for many years.
A combination therapy of interferon alpha and ribavirin is currently recommended by the National Institute for Clinical Excellence (NICE) for the treatment of moderate to severe hepatitis C.
Prevention measures introduced to tackle HIV among injectors appear to have been less effective in containing the spread of HCV when compared to HIV.

The scale of the problem among injecting drug users in Scotland

By June 2001 there were 12,680 known cases of hepatitis C antibody positive in Scotland. Of these, 60% were known to have injected drugs.
The estimated number of HCV infected current injectors in Scotland is 10,000.
In addition to this, there is an unknown number of HCV infected past injectors.
Scottish drug users continue to inject and to share their injecting equipment. In 2000/01 over one third of current injectors in contact with services reported that they had shared injecting equipment in the previous month.

An overview of possible prevention strategies

There is a wealth of prevention measures that can potentially impact on the level of HCV in the injecting population. Some interventions will have the primary aim of preventing or reducing HCV transmission. Other interventions will have prevention or reduction of HCV transmission as one of a range of desired outcomes.
Prevention approaches can be designed to reduce the number of injectors in a population. Examples include ensuring access to effective drug treatment, preventing initiation into injecting and promoting a move away from injecting to smoking.
Prevention approaches can also be designed to reduce the sharing of injecting equipment by ensuring access to needle and syringe exchange facilities, ensuring access to sufficient numbers of needles and syringes and by providing wider injecting paraphernalia (e.g. citric acid, water, filters and spoons).
Prevention approaches can also aim to improve knowledge of HCV and the risk factors by providing education and training to injectors, drug using peers and to service providers. Such approaches include peer education and staff training.
Overall, a strategy to prevent the spread of HCV should clearly not rely upon one of the above approaches, but should tackle the problem in a range of ways, with a combination of interventions.

Effective Interventions Unit, April 2002

The Scottish Government