Theme: Epidemiology & Public Health Research Year: 2019
Background: Direct-acting antiviral therapies (DAA) remove many barriers to the treatment of people
who inject drugs (PWID). However, reinfection among PWID remains a concern and may hamper
elimination efforts. We estimated HCV reinfection rates among DAA-treated individuals, including PWID
in a population-based cohort study in British Columbia (BC), Canada.
Methods: We analyzed data from the BC Hepatitis Testers Cohort which included ~1.7 million individuals
screened for HCV in BC. We followed HCV-infected individuals treated with DAAs who achieved
sustained virologic response (SVR) and had ≥1 subsequent HCV RNA measurement from SVR until
October 9, 2018. Reinfection was defined as a positive RNA measurement after SVR. PWID were
identified using a validated algorithm and classified based on recent (≤3 years) or former (>3 years
before SVR) injection drug use (IDU). Crude reinfection rates per 100 person-years (PYs) were calculated.
Results: Of 4,563 individuals who received DAA treatment, the majority were male (n=2,972, 65%), born
before 1965 (n=3,730, 82%), and were PWID (n=2972, 65%). Among PWID, 907 (20%) and 2065 (45%)
were classified as recent and former IDU, respectively, and 20% were on opioid-agonist therapy (OAT).
We identified 43 reinfections during 3,267 PYs (1.32/100 PYs) accumulated over one year of follow-up
post SVR. Reinfection rates were higher among people with recent (n=19, 2.55/100 PYs) and former IDU
(n=20, 1.42/100 PYs) than non-PWIDs (n=4, 0.36/100 PYs). Cumulative incidence curves showed an
increase in incidence among PWID over time. Among people with recent IDU, reinfection rates were
higher among those born after 1975 (7.1/100 PYs) or co-infected with HIV (3.6/100 PYs).
Conclusions: Population-level reinfection rates after DAA therapy are higher among PWIDs, especially
those with recent IDU compared to those with no IDU. Rapid scale-up HCV treatment along with high
coverage of harm reduction services for high risk groups will be needed to achieve HCV elimination.
Disclosure of Interest Statement: MK has received grant funding via his institution from Roche
Molecular Systems, Boehringer Ingelheim, Merck, Siemens Healthcare Diagnostics and Hologic Inc.