Using hepatitis C virus and herpes simplex virus-2 to track HIV among injecting drug users in New York City

Objective: To explore the potential utility of hepatitis C virus (HCV) seroprevalence as a biomarker for injection risk, and herpes simplex virus-2 (HSV-2) as a biomarker for sexual risk among injecting drug users (IDUs). We examined the relationships between HCV and HIV and between HSV-2 and HIV among injecting drug users in New York City relative to the large-scale implementation of syringe exchange in the mid-1990s. Methods: 397 injecting drug users were recruited from a drug detoxification program in New York from 2005 to 2007. Informed consent was obtained, a questionnaire covering demographics, drug use and HIV risk was administered. Blood samples were tested for antibody to HIV, HCV and HSV-2. Results: Among all subjects, HIV prevalence was 17%, HCV prevalence 72% and HSV-2 prevalence 48%. Among IDUs who began injecting before 1995, HIV was 28%, HCV serostatus was strongly associated with HIV serostatus (AOR = 8.96, 95% CI 1.16-69.04) and HSV-2 serostatus was not associated with HIV serostatus (AOR = 1.31, 95% CI 0.64-2.67). Among subjects who began injecting in 1995 or later, HIV was 6%, HCV was not associated with HIV (AOR = 1.04, 95% CI 0.27-4.08) and HSV-2 serostatus was strongly related to HIV serostatus (AOR = 10.71, 95% CI 1.18-97.57). Conclusions: HCV and HSV-2 HCV and HSV-2 may provide important new tools for monitoring evolving HIV epidemics among IDUs. Reconsideration of the current CDC hierarchical transmission risk classification system may also be warranted.