Hepatitis C Vaccine Remains Elusive
Several types of Hepatitis C viruses exist, and unfortunately, recovering from one virus does not guarantee protection from future HepC viruses, according to new research from the University of British Columbia (UBC) Faculty of Medicine.
The findings, published September in Scientific Reports, provide further evidence that a prophylactic vaccine, consisting of a cocktail of virus types, might be the way forward to controlling the hepatitis c virus.
Hepatitis C is a liver infection caused by the HCV, a blood-borne virus.
Most people today become infected with the Hepatitis C virus by sharing needles or other equipment to inject drugs. For some people, hepatitis C is a short-term illness but for 70%–85% of people who become infected with Hepatitis C, it becomes a long-term, chronic infection.
A hepatitis C vaccine is not available.
Although vaccines exist for hepatitis A and hepatitis B, development of a hepatitis C vaccine has presented challenges. No vaccine is currently available, but several vaccines are currently under development.
Nazrul Islam, a post-doctoral fellow in the UBC School of Population and Public Health and lead author of the article, explains the toll that hepatitis C takes on people and society, and the barriers to preventing it.
HCV affects about 68,000 people in British Columbia.
“While newer hepatitis C treatments, such as direct-acting antivirals, are highly effective, with cure rates of around 95 per cent, and few side-effects, they are very expensive, costing from $45,000 to up to $110,000 for a 12- to 24-week course in British Columbia,’ said Islam.
“Since people are at risk of a second (or third) infection, even after a successful treatment, reinfections add a significant monetary toll on the health system. Thus, an effective hepatitis C vaccine is needed to prevent infections and re-infections, which will ultimately help the health system as well as patients,” said Islam.
Previous studies have indicated that reinfection with HCV results in a higher likelihood of clearing the virus and a shortened period of infection.
In this study, UBC followed individuals who cleared their first infection, and became reinfected with the same or a different virus type, and observed whether they were able to clear the second infection.
People who were able to clear their first infection without any treatment, were almost half as likely to clear their second infection if the second infection was caused by a different virus type than the first.
“This indicates that protection against a particular HCV virus type is not able to protect against a different HCV virus type,” said Islam.
While a vaccine that prevents infection is the ultimate goal, it is not yet a reality.
Based on our results, and given the genetic diversity of HCV virus types, it is probably more pragmatic to develop a prophylactic vaccine containing a mix of HCV types that aids clearance of the virus, creating partial protective immunity.
This would shorten viral presence in the body, and prevent long-term consequences of viral persistence including liver cirrhosis and liver cancer.
This will not only improve peoples’ quality of life, it will save a significant amount of public expenditure by reducing HCV treatment cost, and health care costs of treating liver-related complications, Islam added.