Hepatitis C in injecting drug users in the North West A Multi-Agency Study
Penny A. Cook, Jim McVeigh, Apurva Patel, Qutub Syed, Ken Mutton and Mark A. Bellis

EXECUTIVE SUMMARY

Viruses such as HIV, hepatitis C and hepatitis B that are transmitted in the blood pose a major health threat for people who inject drugs. Hepatitis C is a particular cause for concern for several reasons. Firstly, its prevalence is extremely high among injecting drug users (IDUs) (reported levels range between 60 - 80%). Secondly, no vaccine is as yet available, and the rapid mutation rate of the virus makes the imminent development of one unlikely. Thirdly, treatment is often ineffective, with even the most advanced treatment available clearing the infection on only 40% of occasions. Finally, a high proportion of cases (around 80%) become chronically infected, and of these, around 20% go on to develop serious liver damage, such as cirrhosis or hepatic carcinomas. Because individuals can have many years of asymptomatic infection before presenting to health services with chronic disease, the scale of the problem is hard to assess. Moreover, in IDUs infection with multiple strains of hepatitis C or co-infection with hepatitis B or HIV is common, and this exacerbates damage to the liver.

In the wake of the HIV crisis and the provision of needle exchange schemes, IDUs reduced the levels of high risk sharing behaviour. However, hepatitis C is much more efficiently transmitted in small amounts of blood, and infections occur via indirect sharing of other injecting paraphernalia. At present there is no national strategy for the screening and treatment of IDUs. Treatment requires a high level of compliance, and has unpleasant side effects such as depression. Since IDUs often display chaotic behaviour, they are generally not considered suitable for treatment. However, taking a hepatitis C test and the counselling that accompanies it may represent an opportunity for addressing risk behaviours and possibly stabilising drug use.

Aims

Reviewing current knowledge about hepatitis C epidemiology reveals a number of factors that are at present unmeasured but necessary to implement effective and economic policies for hepatitis C prevention and treatment. Key amongst these is the level of infection in wider drug injecting communities in the North West (not just those requesting a test or in treatment at specialist drug agencies). Equally however, additional data are needed on the risk behaviours associated with infection and information is required on whether and how individuals change such behaviour once aware of their hepatitis C serostatus. Consequently, a group of IDUs in the North West were recruited in order to:

1. compare the prevalence of hepatitis C among drug users accessing different types of service, and among drug users not accessing services
2. establish the extent of co-infection of hepatitis C and hepatitis B
3. elucidate risk factors for hepatitis C infection
4. explore the effect of knowledge of previous hepatitis test results on behaviour
5. identify factors that predict sharing of equipment
6. establish a cohort for follow up and establish feasibility of monitoring hepatitis C infection among drug using populations using saliva samples (results not covered in this report).

Key Findings and Recommendations

This study has identified the following key findings and recommendations:

• Among the 341 injecting drug users in this study, the prevalence of hepatitis C was 53.1% (181 people), hepatitis B 26.6% (89 people) and 19.0% (65 people) were co-infected with hepatitis C and B (Section 4.1). Although the study was relatively small, different areas of study recruitment provided different levels of hepatitis C infection, with those presenting to drugs services requesting a test or those in treatment with community drugs teams having the highest prevalence. Those who had been for a hepatitis C test before this study were 1.68 times more likely to be hepatitis C positive in this study, again suggesting that people presenting for tests are more likely to be hepatitis C positive (Section 4.4)

  Models of health impact of hepatitis C should consider potential variations in prevalence rates between settings and recognise that most studies to date have assessed those most at risk of infection.

• We crudely estimate that there are around 30,200 drug users currently in contact with services in the North West. Using estimates of the proportion of these injecting drugs, and applying the hepatitis C prevalence of 53% found in this study, we estimate that there are 12,800 people currently chronically infected with hepatitis C. Of these, 2,600 will go on to develop serious liver damage (cirrhosis or hepatic carcinoma) (Section 5.1). This figure does not include the hidden population of drug users, previous or new users entering the drug-using population.

  Health Authorities should anticipate the increase in treatment costs associated with treating this high number of patients with liver damage over the next twenty years.

• Those who are infected with hepatitis C are four times more likely to also be infected with hepatitis B (Section 4.1). Co-infection increases the risk of progression to serious disease.

  Current hepatitis B vaccination programmes should attempt to protect people early in their drug injecting career before exposure to hepatitis C.

• Having ever visited prison, and the number of prison stays, were both strong predictors of hepatitis C infection (Figure 1). Prison represents a potential injecting and non-injecting risk for hepatitis C. For example sharing of personal items such as razors may lead to infection, and those few study participants infected but not identified as injectors were more likely to have been in prison.

  More awareness of these other, albeit low risk, activities is needed generally but in particular in prisons.

• Chaotic behaviours such as polydrug use (Figure 3), use of less commonly misused drugs (Section 4.3) and a longer history of injecting (Figure 2) all predicted hepatitis C infection.

  Harm reduction measures can be targeted at such high risk groups and predictors identified in this study can be used as indicators as to which populations or individuals are at most risk of infection or most likely to be infected.

• Significant levels of sharing were revealed. Almost 40% had shared some form of injecting equipment over the previous four weeks, and 7% had shared needles (Table 4). Consistent with more chaotic behaviour, sharing injecting equipment is more likely to occur in those with polydrug use (Section 4.5). Also, sharing injecting equipment is most common in new injectors (those who have been injecting for up to five years) (Figure 5).

  Work is urgently needed to reach young vulnerable groups of drug users who have recently begun injecting or may progress to injecting drugs. Such work requires education on the risks of injecting to reduce high risk behaviours or ideally prevent them even before they begin.

• A previous positive result for hepatitis C did not appear to result in a change in sharing behaviour (Section 4.4). However, those who had presented for previous tests were more likely to be reformed sharers (i.e. not currently sharing). This may be because counselling received at the time of the test was successful in reducing subsequent risk behaviour regardless of the actual results of the test. However, it may relate to those asking for a test already having decided to protect their health.

  Further work should examine in more detail the links between hepatitis C testing and the identified reduction in sharing behaviour.

• Sharing injecting equipment is more likely to occur in smaller groups of fellow users (Figure 4), possibly because the user feels safe among friends or with a partner. The high prevalence of hepatitis C in drug users in the North West means sharing with anyone carries a high risk of hepatitis C infection.

  Information about the risks of sharing should stress this includes close friends and sexual partners. Health information should also help users address the problems around refusing to share with a partner.