Aims Young injection drug users (IDU) are at high risk for hepatitis C virus (HCV). We sought to determine whether perceiving one's injecting partner to be HCV positive was associated with decreased odds of engaging in receptive needle/syringe sharing (RNS) or ancillary equipment sharing (AES) with that partner.
Design Cross sectional study.
Setting 2003 to 2007 in San Francisco.
Participants 212 young (under age 30) IDU who were HCV antibody negative reported on 492 injecting partnerships.
Measurements Self-reported RNS and AES within injecting partnerships.
Findings RNS and AES (in the absence of RNS) occurred in 23% and 64% of injecting partnerships in the prior month. The odds of engaging in RNS were significantly lower for relationships in which the participant reported that his/her partner was HCV positive (odds ratio [OR] 0.49; 95% confidence interval [CI] 0.25–0.95). This association was attenuated when adjusted for reusing one's own needle/syringe (adjusted OR 0.57; 95% CI 0.28–1.15). The odds of engaging in AES were lower for participants who did not know the HCV status of their partner, only among non-sexual partnerships (OR 0.47; 95% CI 0.29–0.76).
Conclusions Because perceiving one's partner to be HCV positive was associated with decreased RNS, increased HCV testing and partner disclosure may be warranted. AES was common and was decreased only among non-sexual partnerships in which the HCV status of the partner was not known. This suggests that interventions to reduce AES in young IDU must be widespread.