WEDNESDAY, Jan. 4 (HealthDay News) -- A vaccine to protect
against the hepatitis C virus, which can cause severe liver damage
and even liver cancer, might be possible -- but it's likely years
away, researchers are reporting.
There is currently no vaccine for hepatitis C, which afflicts an
estimated 170 million people worldwide.
Like HIV, the hepatitis C virus mutates easily and has always
been considered a difficult pathogen to immunize against because
it's constantly changing. However, preliminary research by British
and Italian scientists suggests that the virus might one day be
beatable due to a novel approach.
The researchers treated 41 healthy volunteers with a vaccine
designed to generate a response by T cells (infection-fighting
cells) against the virus' internal proteins, instead of aiming to
create an antibody attack on the ever-changing outer coat of the
virus. Study lead author Dr. Paul Klenerman, a senior research
fellow at Oxford University's Nuffield Department of Clinical
Medicine, said the new vaccine is based on research by a biotech
company in Italy. The researchers are calling it the first clinical
trial of a hepatitis C vaccine in humans.
The inside of the virus is much more stable than its outer coat,
Klenerman explained, and it's also headquarters for "crucial pieces
of machinery." He said the researchers used a chimpanzee-based
adenovirus (similar to the common cold virus) as a method of
vaccine transmission, and were able to prime a large cellular
immune response against hepatitis C that lasted for a year -- the
length of the study.
But many questions remain to be answered, Klenerman said. "At
the moment the trial is just Phase 1 and it looked at safety and an
appropriate dose. It needs to go through at least a Phase 2 trial
to show whether it's protective. That trial would probably take two
or three years," he said.
Klenerman added that even if the researchers do develop a safe,
effective vaccine, it's not certain whether it would protect
against different strains of hepatitis C.
"This vaccine is based around one particular genotype -- or strain. The virus itself is very variable. So there's a chance that even if it works well against one strain, it could be less effective against other strains. Viral variation is really a big challenge," he said.
The study is published in the Jan. 4 issue of
Science Translational Medicine.
Commenting on the trial, Dr. Andrew Muir, director of
gastroenterology and hepatology research at the Duke Clinical
Research Institute, said: "It's a novel approach toward a vaccine
we've never had much enthusiasm for. We'd been told it's unlikely
there would be a hepatitis C vaccine."
Muir said that, while many questions remain, if a hepatitis C
vaccine were developed, it would be a boon. "Treatment is
incredibly expensive," he said, with the current cost ranging from
about $50,000 to $100,000.
Dr. Bruce Bacon, professor of internal medicine in the division
of gastroenterology and hepatology at St. Louis University School
of Medicine, said the payoff from such a vaccine is likely years
away. "It's early yet and a lot has to be done to prove efficacy.
If you can develop a vaccine that's effective, you can
significantly reduce the burden of disease, but maybe the burden of
disease 20 years from now."
Prevention and screening efforts, and developing effective
medications may be more practical areas of focus for now, Bacon
People are risk of hepatitis C infection include those on
long-term kidney dialysis; have regular contact with blood at work
(such as health-care workers); and those who use injectable street
drugs, according to the U.S. National Institutes of Health.
To learn more about hepatitis C, visit the
U.S. National Digestive Diseases Information
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