Hepatitis C viral clearance in an intravenous drug-using cohort in the Dublin area.

BACKGROUND The rate of spontaneous HCV viral clearance is reported as 20-25% but recent data indicate a higher frequency in some cohorts. The rate of spontaneous clearance in intravenous drug users has not been reported in an Irish setting. AIMS To determine the rate of spontaneous hepatitis C viral clearance and genotype in an Irish intravenous drug-using cohort. METHODS Drug users attending five drug treatment clinics in the Dublin were investigated. Data were prospectively recorded from January 1997 to June 2001 and follow-up testing completed in 2003. There were 496 HCV antibody positive patients identified and assessed for HCV RNA clearance. All were HIV and hepatitis B negative, 68.8% were male. RESULTS HCV RNA negativity (viral clearance) was documented in 38% of patients. Viral clearance was 47.4% in females and 34.5% in males (p = 000.6). Clearance was independent of age or duration of intravenous drug use. Viral clearance as defined as two negative consecutive HCV RNA tests, a minimum of one year apart, was sustained in 82.2% at two-year follow-up, giving an overall viral clearance of 31.1%. HCV genotype 1 and 3 were most commonly identified at 48.8% and 48.5% respectively in those with chronic infection. CONCLUSIONS Spontaneous HCV viral clearance occurs at a higher frequency than previously reported. Genotype 1 and 3 are commonest in the patient cohort.