Examination of the risk of reinfection with hepatitis C among injecting drug users who have been tested in Glasgow

Abstract

a b s t r a c tBackground: Unsafe injecting practices put injecting drug users (IDUs) at repeat exposure to infection with the hepatitis C virus (HCV). It has not yet been determined if spontaneously clearing one's primary infection influences the risk of reinfection; our aim was to estimate the relative risk of reinfection in IDUs who have cleared the virus. Methods: We conducted a retrospective study using a large database of HCV test results covering Greater Glasgow Health Board during 1993-2007 to calculate rates of infection and reinfection in current/former IDUs. The relative risk of (re)infection in previously infected compared with never-infected IDUs was estimated using Poisson regression, adjusting for age at study entry, sex, and calendar period of test. Results: Although the rate of reinfection in IDUs who were HCV antibody-positive, RNA-negative at baseline was lower (7/100 person-years, 95% CI: 5-9) than the rate of acute infection in IDUs who were HCV antibody-negative at baseline (10/100 person-years, 95% CI: 9-12), the risk of reinfection was not significantly different than the risk of initial infection (adjusted rate ratio = 0.78, 95% CI: 0.57-1.08). Conclusion: We found only weak evidence for a reduced risk of HCV reinfection in IDUs who had cleared their previous infection. Further research among those who have cleared infection through antiviral therapy is needed to help inform decisions regarding treatment of IDUs.

The effects of needle-sharing and opioid substitution therapy on incidence of hepatitis C virus infection and reinfection in people who inject drugs

“…As such, this study strengthens the evidence [5, 10] that HCV incidence in Australian PWID has declined over the past decade or more. Our study also reaffirms our previous finding that, descriptively, HCV reinfection incidence is greater than the rate of naive infection [22], although this is not universally the case in longitudinal cohorts of PWID [3, 23]. However, these data suggest a substantially greater decline in HCV reinfection (compared to naive infection) in PWID in Melbourne.…”

Factors associated with spontaneous clearance of chronic hepatitis C virus infection

“…We also accept the possibility that a high HCV re-infection rate post clearance amongst PWIDs may be masking the incidence of spontaneous clearance in our cohort [6,40]. However, one study based in NHSGGC reported a trend towards a lower incidence of re-infection post spontaneous clearance [41] as described in previous studies [42].…”

Association between harm reduction intervention uptake and recent hepatitis C infection among people who inject drugs attending sites that provide sterile injecting equipment in Scotland

“…Notably, the RDS study may have overestimated HCV incidence due to detection of a transmission cluster; the authors note that exclusion of this cluster would result in an incidence rate of 18-25 per 100 person-years (Hope et al, 2011). Historically, regional incidence rate estimates among PWID in Scotland have ranged from 10 to 29 per 100 person-years (McDonald et al, 2012;Roy et al, 2007). However, whereas the latter estimates were generally confined geographically, our estimate applies to mainland Scotland.…”