Around 70 million people worldwide have chronic hepatitis C virus (HCV) infections. This may lead to the development of severe liver diseases such as cirrhosis or liver cancer. New curative therapies have significantly improved the treatment options. However, these therapies are expensive and therefore often unavailable, especially in countries with high rates of infection. In addition, many people with HCV infection are unaware of their infection – it is estimated that only 20 percent of all infections worldwide are diagnosed. Furthermore, virus elimination, be it after an untreated infection or following successful treatment, does not protect against re-infection with HCV. Unfortunately, the number of cases of new or recurring infections worldwide still exceeds the number of cures. Therefore, the WHO’s goal of reducing the number of new HCV infections by 90 percent by 2030 will be almost impossible to achieve without a vaccine.
Understanding natural protection paves the way to hepatitis C vaccine development
A major challenge in the development of a hepatitis C vaccine is the enormous diversity of the virus. The diversity is essentially driven by a high error rate during viral genome replication, which constantly creates new virus variants – totaling up to an estimated trillion variants per infected person per day. We are working intensively on the development of a vaccine that generates protective immunity against as many virus variants as possible. An important starting point is the observation that approximately 30 percent of people infected with HCV spontaneously eliminate the infection, i.e. develop an effective antiviral immune response. Both neutralizing antibodies and specific immune cells are key players in self-limiting HCV infection. The DZIF scientists therefore aim to identify the essential components of antibody and immune cell responses against HCV based on which they will develop a prophylactic vaccine candidate. A large cohort of hepatitis C patients has been established with the help of the HepNet study house of the German Liver Foundation which is being used to study immune responses in humans.