Can intranasal drug use reduce HCV infection among injecting drug users?

Background: Preventing HCV infection among people who inject drugs is a difficult public health challenge. We examined the potential role of intranasal drug use in reducing HCV acquisition. Methods: Subjects were recruited from IDUs entering the Beth Israel drug detoxification program from 2005 to 2010. A structured interview was administered and serum samples were collected for HCV testing. Results: 726 active injecting drug users were recruited from 2005 to 2010. HCV prevalence was 71%, 90% reported recent heroin injection and 44% reported recent intranasal heroin use. In a multiple logistic regression analysis, being HCV seropositive was associated with more years injecting, Latino ethnicity, previous testing for HCV, and recent injection of speedball, and negatively associated with recent intranasal use of heroin (AOR = 0.52, 95% CI 0.33-0.82) and intranasal use of speedball (AOR = 0.41, 95% CI 0.31-0.80). The association between intranasal heroin use and lower HCV seroprevalance was observed among both new injectors and persons with long injecting histories (16+ years since first injection). Conclusion: Encouraging intranasal use as an alternative to injection among persons currently injecting drugs may be a viable strategy for reducing HCV transmission.