Theme: Clinical Research Year: 2022
The introduction of direct-acting antiviral therapy (DAA) marked a new treatment era for hepatitis C
virus (HCV) infection. Despite the success of DAA treatment, a major hurdle has been re-infection among
people who inject drugs (PWID) or engage in other high-risk behaviours. The objective of this study was
to assess the re-infection rates in individuals who were successfully treated with DAAs and to identify
common underlying factors.
Data were extracted from the Hepatitis C Positive and At-Risk (HEAR) database on all individuals who: 1)
underwent direct acting antiviral (DAA) therapy to treat HCV from December 2014 to November 2020,
2) have a history of substance use, and 3) had at least one HCV viral load collected > 12-weeks posttreatment. Follow-up time was calculated from the last day of treatment to the date the latest HCV viral
load was collected.
Overall, 143 patients were included with a mean age of 46.2 years and total follow-up time of 164.6
years. At the time of treatment start, snorting and/or injection drug use (IDU) was reported by 49.0% in
the preceding 2 years. A total of 17 re-infections were identified for a rate of 10.3 (95% CI 6.4-16.6) reinfections per 100 patient years. Younger age, lack of primary care, unstable housing and recent IDU
(within 6 months) appear to be factors pre-treatment that may increase the likelihood of re-infection.
Despite the success of DAA therapy to treat individuals with HCV, the results of this study further
underline the disproportionate re-infection rates in those engaging in high-risk behaviours. In addition,
we identified factors such as younger age, lack of primary care and unstable housing as risk factors for
re-infection. Within these high-risk populations, education about the risks of re-infection as well as
public health programs to reduce risk could be beneficial.
Disclosure of Interest: