Hepatitis C virus primary and reinfection among MSM in the DAA era Changes in infections, behaviours and prevention

Hepatitis C virus (HCV) is a type of viral hepatitis which is primarily transmitted by blood-to-blood contact. Since 2000, outbreaks of sexually transmitted HCV have been reported among men who have sex with men (MSM) with HIV in high-income countries, including the Netherlands. The introduction of highly effective direct-acting antiviral treatment in 2014 has substantially changed the epidemiology of HCV in this group. This thesis examines recent HCV epidemiology among MSM, explores behavioural changes after HCV clearance, and aims to develop and implement interventions to potentially reduce the risk of HCV reinfection.
Chapters 2 and 3 investigate the epidemiology of HCV among MSM without HIV who are not using HIV pre-exposure prophylaxis (PrEP), and among MSM and transgender persons using PrEP in the Netherlands. Chapter 4 validates the HCV-MOSAIC risk score as a tool to support testing for HCV reinfection among MSM with HIV. In chapter 5, we describe changes in HCV-related behaviours before, during and after treatment, comparing the former pegylated interferon regimen with modern DAA-based therapy. Chapter 6 and 7 present different behavioural trajectories following HCV clearance among MSM with HIV and within an international cohort of people with HIV. In chapter 8, we examine the impact of the COVID-19 and mpox outbreaks on behaviours associated with HCV among MSM with a cleared infection. Finally, chapter 9 outlines a study protocol including two interventions – home-based self-sampling for HCV testing and an online behavioural intervention – aimed at reducing behaviours and prevent onward transmission.