Screening, linkage to care and treatment of chronic hepatitis C infection in high-risk populations in Hong Kong

Abstract

Background: The identification of high-risk groups for micro-elimination of hepatitis C virus (HCV) infection is a pragmatic strategy for regions where the overall prevalence of HCV is not high. We aimed to screen for HCV and provide linkage to care (LTC) for high-risk populations in Hong Kong. Methods: Between 2019 and 2021, we initiated the Conquering Hepatitis vIa Micro-Elimination (CHIME) program and performed a prospective study by forming an outreach team to conduct site visits to halfway house or drug rehabilitation centers run by non-governmental organizations in Hong Kong. Subjects with history of illicit drug use, needle sharing, or prior imprisonment were included. We performed point-of-care (POC) test for antibody to HCV (anti-HCV), and venipuncture for subjects with positive POC results to check for HCV RNA. Viraemic subjects were invited to attend the LTC clinic for counselling and treatment with direct acting antiviral (DAA). Results: 22 site visits were conducted and 396 subjects were screened. A total of 229 subjects had positive POC (57.8% anti-HCV+) with 100% concordance with serum anti-HCV testing, while 187 subjects were found to have HCV infection (47.2% RNA+). Compared to non-viraemic subjects, viraemic subjects were older, more likely to be divorced, unemployed, had lower education level, with longer duration of heavy cigarette smoking and illicit drug use (Figure 1A). Among 124 viraemic subjects (66.3% linkage) who attended the LTC (median waiting time: 21.9 weeks), the most predominant genotype was 6 (59.2%) (Figure 1B). Two-thirds (66.9%) subjects had abnormal liver biochemistries and 21 (16.9%) subjects were cirrhotic (defined by liver stiffness >12.5 KPa at transient elastography, with only 1 being Child Pugh class B/C). Co-infection with hepatitis B virus and human immunodeficiency virus was found in 6.4% and 0.8%, respectively. Among 104 subjects started on DAA (96% pan-genotypic regimen), the sustained virological response rate was 98%, with no serious side effects reported. Non-engagement in care was common (18.7% 1st visit, 8% 2nd visit, 6.3% 3rd visit), and was associated with unemployment, longer duration of smoking, and prolonged illicit drug use (Figure 1C). Conclusion: The CHIME program successfully allowed high-risk populations with HCV in Hong Kong to be identified and linked to care with excellent treatment outcomes. Subject engagement needs to be improved to enhance efficiency of micro-elimination efforts.