Association between first injection risk behaviors and hepatitis C seropositivity among injecting drug users.

HCV infection is rapidly acquired after drug addicts first inject drug intravenously. The risk behaviors accompanying the first intravenous substance injection are not well known. We used in 1997 a structured questionnaire to investigate the relationships between risk behaviors at the first injection and current reported HCV status. We interviewed 151 injecting drug users from four treatment centers and one prison in Paris. Risk markers for reported HCV seroconversion were explored by use of logistic regression models. One hundred and forty-three injecting drug users (95%) agreed to participate in the study. At the first injection, 50% shared preparation equipment; 22% borrowed and 26% lent injecting equipment. At the time of the study, 46% reported that they were HCV-positive. Sharing preparation equipment (odds ratio=3.1; 95% confidence interval: 1.2-7.8) and lending injection equipment (odds ratio=3.0; 95% confidence interval: 1.1-8.5) during the first injection were independently associated with reported HCV seropositivity. The high-risk behaviors accompanying the first intravenous injection of drugs justifies the implementation of specific prevention measures, aimed at young drug users who have not started to inject.