Incidence Of HCV Among Participants In The Stockholm Needle Exchange Program

Author: Kåberg M, Navér G, Hammarberg A, Weiland O

Theme: Epidemiology & Public Health Research Year: 2017

Introduction: The hepatitis C virus (HCV) epidemic is driven by people who inject drugs (PWID). Effective prevention of HCV transmission includes needle exchange programs (NEP), opiate substitution treatment (OST) and scaled-up HCV treatment. More data on HCV incidence need to be presented to better understand HCV incidence and associated risk factors in different HCV settings.

Methods: 2320 PWID were enrolled in the Stockholm NEP. All responded to baseline questions and were tested for HCV every three to six months. Overall, 59% were HCV RNA positive. After exclusion of participants not susceptible for HCV infection and participants without follow-up testing, 594 participants were included in this retrospective cohort study on incidence of new HCV infections between April 8th 2013 and September 23rd 2016. Mean follow-up time was 2.1 years.

Results: The incidence rate of HCV infection was 16.3 per 100 person years (PY). Female sex, homelessness and low education level had significant impact on the risk of contracting HCV in the anti-HCV negative group. The relationship between risk factors and re-infection were more complex in the anti-HCV positive but HCV RNA negative group, with no significant differences between those who became re-infected or not.

Discussion: HCV treatment in active PWID is currently being scaled-up in the world. Our data on the HCV incidence in PWID in Stockholm could be used as a proxy for possible re-infection rates post HCV treatment in a high HCV prevalence setting of active PWID. A continuous high level of HCV surveillance is needed within the NEP to effectively identify continuous HCV transmission.