John Law, a research associate, is part of a team that has made a significant discovery in the search for a vaccine against hepatitis C at the University Hospital in Edmonton. Photograph by: Ed Kaiser, Ed Kaiser
By Jodie Sinnema, Postmedia NewsFebruary 15, 2012
EDMONTON — A University of Alberta research team is one step closer to discovering a vaccine for hepatitis C that appears to work against all the major strains of the disease.
Michael Houghton, a researcher at the Li Ka Shing Institute of Virology at the university, says his discovery was unexpected. That's because there are six major strains of hepatitis C and hundreds more subtypes infecting 170 million people around the world. Hepatitis C is spread through contaminated blood and can be associated with needle-sharing, medical procedures involving unsterilized equipment or blood transfusions.
Vaccines, made with the antibodies of specific strains, tend to only work against those specific disease types. Think, for instance, about the flu vaccine and how it covers only certain strains expected to circulate during a given flu season.
Houghton said new data from the University of Alberta shows his vaccine, made from one strain of the hepatitis disease, produces antibodies that can neutralize all the hepatitis C types around the world.
"I think that's great news for our efforts to develop a vaccine for hepatitis C," said Houghton, a world-renowned expert in medical microbiology and immunology who discovered the hepatitis C virus in 1989. He presented his recent findings during Wednesday's Canada Excellence Research Chairs Summit in Vancouver. "It's a very unexpected result and it's guiding us toward the development of a successful hepatitis vaccine."
Such a vaccine was thought impossible and impractical, since hepatitis C is more heterogeneous — or has more varieties — than HIV.
"I think it's a very big step forward," he said. "I've been working on the vaccine for 15 years (and) for so many years, the field felt that antibodies would be very restricted in their neutralizing ability, that you could only neutralize the same strain that the vaccine was derived from."
John Law, Houghton's research partner, said preliminary tests show the vaccine blocked some strains from entering a person better than others, with success rates ranging from 40 per cent to 100 per cent. He said the effectiveness could be improved in clinical trials by playing with the dosage.
Houghton said while it would take five to seven years before such a vaccine could hit the market — it must be proven safe and effective in large clinical trials involving humans — he said the vaccine could also help those already infected with the disease. Of the millions who carry the infection, up to 20 per cent develop chronic illness, including cirrhosis of the liver.
A drug cocktail already on the market cures 70 per cent of those infected with hepatitis C, Houghton said. He said further research needs to determine if a combination of that antiviral with the new vaccine could increase the success rate.
"It may also be beneficial as a therapeutic vaccine," he said. "That does deserve attention in the future."
Dr. Lorne Tyrrell, a hepatitis expert and the Canadian Institutes of Health Research and GlaxoSmithKline chair in virology at the University of Alberta, said if the vaccine proves effective, it will have a global impact. In Egypt, for instance, 10 per cent of the population carries hepatitis C.
"In many parts of the world, the antiviral therapy we currently have for hepatitis C is often out of the reach of most people's affordability so having a (cheaper) vaccine that could be used to prevent the disease in those countries is particularly important," Tyrrell said.
"There's still a lot of work that needs to be done, but at least it's a clue and an indication that we can develop a potential vaccine for hepatitis C."
jsinnema@edmontonjournal.com
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Also See: Alberta researchers develop vaccine to fight hep C
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