Twin epidemics of new and prevalent hepatitis C infections in Canada: BC Hepatitis Testers Cohort

Naveed Zafar Janjua, Amanda Yu, Margot Kuo, Maria Alvarez, Darrel Cook, Jason Wong, Mark W. Tyndall, Mel Krajden

We characterized the twin epidemics of new and prevalent hepatitis C virus (HCV) infections in British Columbia, Canada to inform prevention, care and treatment programs. The BC Hepatitis Testers Cohort (BC-HTC) includes individuals tested for HCV, HIV or reported as a case of HBV, HCV, HIV or active TB between 1990-2013 linked with data on their medical visits, hospitalizations, cancers, prescription drugs and mortality. Prevalent infection was defined as being anti-HCV positive at first test. Those with a negative test followed by a positive test were considered seroconverters or new infections. Of 1,132,855 individuals tested for HCV, 64,634 (5.8 %) were positive and an additional 3092 cases tested positive elsewhere for a total of 67,726. Of 55,781 HCV positive individuals alive at the end of 2013, 7064 were seroconverters while 48,717 had prevalent infection at diagnosis. The HCV positivity rate (11.2 %) was highest in birth cohort 1945-1964 which declined over time. New infections were more likely to be male, 15-34 years of age (born 1965-1984), HIV- or HBV-coinfected, socioeconomically disadvantaged, have problematic drug and alcohol use and a mental health illness. The profile was similar for individuals with prevalent infection, except for lower odds of HBV-coinfection, major mental health diagnoses and birth cohort >1975. The HCV positivity rate is highest in birth cohort 1945-1964 which represents most prevalent infections. New infections occur in younger birth cohorts who are commonly coinfected with HIV and/or HBV, socioeconomically marginalized, and living with mental illness and addictions.