HCV epidemiology in high-risk groups and the risk of reinfection

Abstract

Injecting risk behaviours among people who inject drugs (PWID) and high-risk sexual practices among men who have sex with men (MSM) are important routes of hepatitis C virus (HCV) transmission. Current direct-acting antiviral treatment offers unique opportunities for reductions in HCV-related liver disease burden and epidemic control in high-risk groups, but these prospects could be counteracted by HCV reinfection due to on-going risk behaviours after successful treatment. Based on existing data from small and heterogeneous studies of interferon-based treatment, the incidence of reinfection after sustained virological response range from 2-6/100 person years among PWID to 10-15/100 person years among human immunodeficiency virus-infected MSM. These differences mainly reflect heterogeneity in study populations with regards to risk behaviours, but also reflect variations in study designs and applied virological methods. Increasing levels of reinfection are to be expected as we enter the interferon-free treatment era. Individual- and population-level efforts to address and prevent reinfection should therefore be undertaken when providing HCV care for people with on-going risk behaviour. Constructive strategies include acknowledgement, education and counselling, harm reduction optimization, scaled-up treatment including treatment of injecting networks, post-treatment screening, and rapid retreatment of reinfections.

Immune protection against reinfection with nonprimate hepacivirus

“…Reinfection following sustained virological response (SVR) has been reported in several studies among high-risk populations, including people who inject drugs (PWIDs) and prisoners. However, these studies are rare and sometimes show inconclusive results (32,41). Important insights regarding reinfection and protection have been gained from earlier experiments in chimpanzees.…”

Phylogenetic and phylodynamic analyses of hepatitis C virus subtype 1a in Okinawa, Japan

“…Although the MSM population was not included in our study, it has been reported that the number of HIV cases among MSM has increased in Okinawa . The HCV transmission network among MSM is international and MSM tourists visit Okinawa from other areas in Japan or overseas . These data suggest that HCV‐1a strains could possibly spread out from the HIV‐positive MSM population in Okinawa into the MSM population in the main islands of Japan or in other Asian countries.…”

“…Additionally, there were some probable transmission routes in the enrolled population that we did not analyse. Although men who have sex with men (MSM), particularly HIV‐positive individuals, have a high risk of HCV infection, they were not included in our patients based on our interview. Therefore, we have not evaluated the impact of MSM behaviour on the spread of HCV infection.…”

Chronic Hepatitis C Treatment in Patients with Drug Injection History: Findings of the INTEGRATE Prospective, Observational Study

“…In developed countries, injecting drug use typically accounts for 20–40% of HCV infections [2]; the prevalence of hepatitis C antibodies in people who inject drugs (PWIDs) is estimated at 67% worldwide [3]. High-risk behaviors among PWIDs (sharing needles, syringes, and other equipment) are common, and are responsible for a high proportion of ongoing transmission in many regions.…”

“…High-risk behaviors among PWIDs (sharing needles, syringes, and other equipment) are common, and are responsible for a high proportion of ongoing transmission in many regions. Among current PWIDs in Europe, median incidence of community-acquired HCV infection is approximately 26 infections per 100 person-years [3]. Furthermore, rates of reinfection following viral clearance are estimated to be between 1.8 and 46.7 cases per 100 person-years [4].…”