A number of studies published in 2004 and 2005 update or advance our knowledge of hepatitis C among drug users in Ireland.

Grogan et al.1 assessed the uptake of screening for, and estimated the prevalence of, hepatitis C in 358 heroin users attending 21 drug treatment clinics in the HSE South Western Area up to December 2001. A one-in-four systematic sample of clients prescribed methadone in the 21 drug treatment clinics in the area in December 2001 was selected from the Central Treatment List. Data collected from the clinical records showed that 88% of the sample had had a test for hepatitis C, of whom 66% had tested positive. These results are in line with those from other studies in a similar setting. The authors point out that the results were ascertained from clinical records and pertain only to those documented in the clinical records. The tests recorded had been administered over an extended time period and those testing negative at their first test may have subsequently sero-converted and not have had a repeat test. In addition, injector status was not ascertained and the authors acknowledge that the proportion of injectors testing positive for each virus would be higher.

A study by O’Sullivan,2 using a cross-sectional survey method, assessed the prevalence of blood-borne viruses among 90 injecting drug users attending an opiate-substitution programme at the Drug Treatment Centre Board. The sample size was estimated using a wide 10% level of precision and a 95% level of confidence. The author obtained adequate blood samples from 65 of the 90 clients interviewed. In total, 72% tested positive for hepatitis C.  

In another published study, Keating and colleagues3 estimated the proportion of hepatitis C positive individuals with each genotype in an intravenous drug-using cohort, and then estimated the proportion that spontaneously cleared the hepatitis C virus. The study followed the progress of 496 hepatitis C antibody-positive individuals attending five drug treatment centres in Dublin. Of the 299 PCR-positive samples that had their genotype determined, genotypes 1 and 3 were the most common (see table). The PCR test detects whether the virus is still in the blood and will show if a person has an ongoing infection.

Number of PCR positive samples of selected hepatitis C antibody positive individuals attending five drug treatment centres in Dublin, by genotype

Of the 496 hepatitis C antibody-positive participants in the sample, 191 (38.5%) were shown to be HCV RNA negative when re-tested, indicating that they had spontaneously cleared the virus. A higher proportion of women (47.4%) than men (34.5%) cleared the virus spontaneously. A higher proportion of those with a history of jaundice (12.0%) than those who reported no history of jaundice (7.9%) cleared the virus.

Smyth et al. 4 examined the contribution of unsafe injecting practices and the social context of injecting in Dublin to infection with hepatitis C. Of the 242 participants who completed the questionnaire, 159 were tested for hepatitis C; of these, 61% tested positive for hepatitis C. After controlling for other factors, the authors found that an increased number of lifetime injecting episodes increased the risk of hepatitis C infection. In relation to the social context, individuals who injected in the home of another injecting drug user were almost five times more likely to test positive for hepatitis C than those who injected in their own home or elsewhere. Individuals who injected in the company of close friends or family members were around three times more likely to test positive for hepatitis C than those who injected with acquaintances.

Cullen et al.5 examined the experiences with respect to risk practices of heroin users attending a general practice for investigation of and treatment for hepatitis C. The study questionnaire had a mix of closed and open questions. At the time of the study, 38 former or current heroin users were registered with the practice. Of these, 25 (66%) agreed to be interviewed. Those interviewed were more likely to be female and older than the other heroin users attending the practice. At the time of the study, 23 of the 25 participants were receiving methadone maintenance. Twenty-two participants said that they had tested positive for hepatitis C and, of these, 15 had consumed alcohol in the week prior to the study. Nine had consumed more than the recommended amount of alcohol per week for their gender. Of note, eight reported neither drinking excessively nor using heroin in the previous six months and were therefore suitable for investigation. Only four of the eight suitable clients were referred for further investigation and one had commenced treatment. Those respondents who reduced their alcohol intake did so because they were concerned about their health, while those who increased their alcohol intake did so to substitute for heroin. Some respondents had a negative perception of liver biopsy; those who had undergone this investigation reported that the procedure was not as difficult to tolerate as expected. Many respondents had negative perceptions of antiviral treatment. The experience of treatment by medical and nursing personnel at secondary treatment services was mixed.

Over two-thirds of opiate users have tested positive for hepatitis C in Dublin. The rate of spontaneous viral clearance for this infection was higher than previously reported. There are a number of barriers to hepatitis C treatment for injecting drug users which need to be addressed so as to encourage uptake of treatment.  

1. Grogan L, Tiernan M, Geoghegan N, Smyth B and Keenan E (2005) Bloodborne virus infections among drug users in Ireland: a retrospective cross-sectional survey of screening, prevalence, incidence and hepatitis B immunisation uptake. Irish Journal of Medical Science, 174(2): 14–20.

2. O'Sullivan P (2004) A study of the prevalence of blood-borne viral diseases in injecting drug users receiving methadone maintenance in the National Drug Treatment Centre at Trinity Court in Dublin. Thesis submitted for membership of the Faculty of Public Health Medicine, Royal College of Physicians of Ireland.

3. Keating S, Coughlan S, Connell J, Sweeney B and Keenan E (2005) Hepatitis C viral clearance in an intravenous drug-using cohort in the Dublin area. Irish Journal of Medical Science, 174 (1): 37–41.

4. Smyth BP, Barry J, and Keenan E (2005) Irish injecting drug users and hepatitis C: the importance of the social context of injecting. International Journal of Epidemiology, 34(1): 166–172.

5. Cullen W, Kelly Y, Stanley J, Langton D and Bury G (2005) Experience of hepatitis C among current or former heroin users attending general practice. Irish Medical Journal, 98 (3): 73–74.