Decreasing Hepatitis C Incidence Among a Population With Repeated Tests: British Columbia, Canada, 1993-2011

Objectives. We estimated HCV incidence among individuals who repeatedly underwent anti-HCV testing. Methods. We studied HCV-negative individuals who had at least 2 tests between April 1992 and September 2012 in British Columbia, Canada. We calculated incidence as the number of new infections per 100 person-years at risk. Results. From 1992 to 2012, 323 598 individuals who persistently tested negative and 7490 HCV seroconverters contributed 1 774 262 person-years of observation time. Incidence rates ranged from 2.66 infections per 100 person-years (95% confidence interval [CI] = 2.07, 3.35) in 1993 to 0.25 infections per 100 person-years (95% CI = 0.21, 0.29) in 2011. Rates declined sharply in the 1990s and declined more gradually in the 2000s. Incidence declined with age; highest incidence rates were among those aged 15 to 24 years. Incidence among male repeat testers exceeded that of female repeat testers across all years, although the gap narrowed over time. Conclusions. Addictions treatment, harm reduction, prevention education, and novel initiatives to remove barriers in health infrastructure need to be intensified for those who inject drugs, particularly men and younger persons.