High hepatitis C seroprevalence in Thai intravenous drug abusers and qualitative risk analysis.

ABSTRACT

One of the high risk groups of hepatitis C virus infection is intravenous drug abusers (IVDAs). The study of HCV seroprevalence and some qualitative risk factors in this target group can be valuable for prevention of the infection. During June to October 1992, a cross-sectional study of 150 intravenous male drug abusers seeking medical treatment at Phranangkhlao and Rajavithi Hospitals was conducted. Blood specimens were collected for determining anti-HCV antibody by EIA. An in-depth interview was carried out searching for some qualitative risk factors in anti-HCV positive and negative IVDAs. It was found that 95.33% of studied IVDAs were positive for anti-HCV antibody. There was no significant difference between the prevalence of anti-HCV and their ages (p > 0.05). The antibody prevalence trended to be higher with the longer duration of drug use. The positive rate of IVDAs who had injected more than 8 years was significantly higher than that of IVDAs who had injected less than 2 years (100% and 85.71), p = 0.004. Alanine amino-transferase (ALT) levels and anti-HIV antibodies were determined. IVDAs with higher levels of anti-HCV had higher percentages of ALT abnormality and anti-HIV positive rates. Data from in-depth interview showed that the longer duration of imprisonment, tattoo/ear piercing, extramarital relations without using condoms, the longer duration of drug use and needle/syringe sharing were potential risk factors for HCV infection in this target group.