Hepatitis C virus vaccines among people who inject drugs

Abstract

Most people who inject drugs (PWID) are infected with hepatitis C virus (HCV), and PWID have the highest risk of HCV infection of any risk group. The incidence of HCV infection is 5%-25% per year, demonstrating continued need for HCV infection prevention in PWID. Existing data in chimpanzees and PWID suggest that protective immunity against persistent HCV infection is achievable. Due to the high incidence of infection, PWID are both the most likely to benefit from a vaccine and a population in which vaccine efficacy could be tested. Challenges to testing a vaccine in PWID are significant. However, the first HCV vaccine trial in at-risk HCV-uninfected PWID was initiated in 2012. The results will likely guide future vaccine development and strategies for vaccination of this and other high-risk populations.

Keywords: hepatitis; hepatitis C virus; injection drug users; vaccine; viral hepatitis.

Figure 1.

Clearance of a primary infection attenuates the infection kinetics of subsequent hepatitis C virus (HCV) infections in injection drug users. A, Maximum HCV RNA concentrations (IU/mL) detected in serum samples obtained during primary and subsequent infections in subjects with sufficient follow-up after the detection of a reinfection. Triangles represent maximum viremia detected in reinfection-persistent subjects. The maximum viremia in each subject during initial infection and reinfection is connected by a line. Median maximum HCV RNA concentration of reinfections was significantly lower than that of primary infections (P < .001). B, Duration of viremia (days) during primary infections and subsequent infections in reinfection-cleared subjects. The duration of initial and reinfection viremia in each subject is connected by a line. The duration of viremia during reinfection was significantly lower than in primary infection (P = .019). Reprinted from Osburn et al [26] with permission. Abbreviation: HCV, hepatitis C virus.