Breakthrough Hepatitis C Vaccine Shows Promising Results

A hepatitis C vaccine manufactured by researchers from Oxford University has shown promising potential in an early clinical trial.

Worldwide, 180 million people are reported to have been affected by hepatitis C. The chronic infection, which persistently attacks the body for years on end, is the leading cause of liver cirrhosis. Hepatitis C had also been associated with cases of liver failure and cancer, an Oxford University statement claimed.

Twenty-five percent of individuals are able to fight off the virus on the first infection — an indication there are immune responses present to combat hepatitis C. However, for people not so lucky, medications to treat the condition are not only expensive, but they also require continuous use to be effective.

The vaccine, which is currently being tested on its efficacy at 2 US sites, is the first one to get this far in testing, the Oxford University release also pointed out.

Working with Okairos, a biotechnology company, investigators published their findings in Science Translational Medicine. By evoking an immune response, the first vaccine is followed by a second treatment 8 weeks later. The subsequent vaccine intends to raise a person’s immune system to a point where they can easily eradicate hepatitis C.

“We assessed a heterologous prime-boost vaccination strategy based on a replicative defective simian adenoviral vector (ChAd3) and modified vaccinia Ankara (MVA) vector encoding the NS3, NS4, NS5A, and NS5B proteins of HCV genotype 1b,” the authors reported.

For their study, the researchers found increased and sustained levels of T cells in volunteers given the vaccine, levels comparable to individuals who can naturally fight off hepatitis C.

The investigators noted, “We show that HCV-specific T cells induced by ChAd3 are optimally boosted with MVA, and generate very high levels of both CD8⁺ and CD4⁺ HCV-specific T cells targeting multiple HCV antigens.” Additionally, they pointed out, “We have developed an HCV vaccine strategy, with durable, broad, sustained, and balanced T cell responses, characteristic of those associated with viral control, paving the way for the first efficacy studies of a prophylactic HCV vaccine.”

Eleanor Barnes, the study’s principal investigator and professor of the Nuffield Department of Medicine at Oxford University, called the results “unprecedented”. Cautious about providing the vaccine the full green light, she was awaiting results of future trials.

“The T cell response is really high, and what's promising is that this is a broad response. A range of different T cells are produced targeting different parts of the hepatitis C virus,” Barnes said. “This is the first highly immunogenic T cell vaccine developed against hepatitis C. We found it to be safe and well tolerated in this group of 15 healthy volunteers. But we won't really know if it works — if it is able to prevent hepatitis C infection – until we have the results of the efficacy studies in the USA.”