Hepatitis C virus (HCV) infection is a major global health concern – 170 million people are infected worldwide, with 3–4 million new infections annually. Many chronically infected patients develop complications of liver disease that include hepatocellular cancer, liver cirrhosis and liver failure.

Despite advances in HCV treatment, a prophylactic vaccine remains the most cost-effective and realistic means to significantly reduce the worldwide mortality and morbidity associated with persistent HCV infection.

A major challenge for HCV vaccine development is the significant viral diversity. However, parts of the viral genome are conserved, making these excellent targets in the context of a T cell vaccine. Hope for a vaccine for HCV lies in the fact that after primary infection spontaneous viral eradication occurs in a significant minority of patients, T cell immunity critically affects the clinical outcome.

The Jenner researchers have developed a HCV vaccine using non-replicating viral-vectored vaccines to induce T-cell responses against a single immunogen incorporating the most conserved proteins of HCV, including non-structural proteins. The use of specially selected conserved viral segments from the non-structural proteins can provide protection against multiple HCV genotypes.

The HCV immunogen was designed using a software-based approach to identify the most conserved and functionally critical protein sequences in all HCV genotypes. The researchers have developed a single immunogen that has been expressed in a simian adenoviral vector.

Immunogenicity trials of the HCV vaccine in mice have shown the induction of abundant T cells against the individual components of the antigen.