"To share or not to share?" Serosorting by hepatitis C status in the sharing of drug injection equipment among NHBS-IDU2 participants.

Background: Persons who inject drugs (PWID) are at high risk for acquiring hepatitis C virus (HCV) infection. The Centers for Disease Control and Prevention estimates there are 17 000 new infections per year, mainly among PWID. This study examines injection equipment serosorting-considering HCV serostatus when deciding whether and with whom to share injection equipment.

Objective: To examine whether injection equipment serosorting is occurring among PWID in selected cities.

Methods: Using data from the National HIV Behavioral Surveillance System-Injection Drug Users (NHBS-IDU2, 2009), we developed multivariate logistic regression models to examine the extent to which participants' self-reported HCV status is associated with their injection equipment serosorting behavior and knowledge of last injecting partner's HCV status.

Results: Participants who knew their HCV status were more likely to know the HCV status of their last injecting partner, compared to those who did not know their status (HCV+: adjusted odds ratio [aOR] 4.1, 95% confidence interval [CI], 3.4-4.9; HCV-: aOR 2.5, 95% CI, 2.0-3.0). Participants who reported being HCV+, relative to those of unknown HCV status, were 5 times more likely to share injection equipment with a partner of HCV-positive status (aOR 4.8, 95% CI, 3.9-6.0).

Conclusions: Our analysis suggests PWID are more likely to share injection equipment with persons of concordant HCV status.