Scientists modifies smallpox vaccine to fight H5N1 bird flu

HONG KONG, March 1 (Xinhua) -- A team of scientists
from the University of Hong Kong and the United States on Sunday said they have
developed a new vaccine strategy against the H5N1 bird flu virus by genetically
modifying a smallpox vaccine.

The new vaccine is potentially a sound solution in
case of an H5N1 bird flu pandemic, which many scientists have been worried
about, said Malik Peiris, a microbiologist and bird flu research authority at
the University of Hong Kong.

Peiris said that the new vaccine has proven safer in
experiments on mice and that "a single vaccine dose will provide rapid
protective immune responses."

It is also expected to enable fast mass production
thanks to the possibility of using cell-culture methods, which could help avoid
potential production bottlenecks as eggs will have to be used in the production
of vaccines currently on offer.

And the existing facilities used for the production
of smallpox vaccines can be used to produce the bird flu vaccines without much
trouble, which can help reduce the costs, said another member of the research
team, adding that alternative strategies available involving genetic engineering
methods have been typically expensive.

The highly contagious H5N1 bird flu virus has
infected hundreds of people around the globe over the past decade, with the
death rate standing at round 60 percent.

There had been no confirmed cases of the virus
spreading from human to human but scientists fear that a genetic mutation might
enable it to jump from human to human someday, thereby leading to a global
pandemic that could kill millions.

Many scientists have been working on the development
of effective vaccines to prevent such a bird flu outbreak and the University of
Hong Kong was among the leaders.

There are now vaccines for sale in the United States
and eggs were essential in manufacturing the vaccines, which might lead to
bottlenecks as eggs may not be readily available in large amount in the case of
a bird flu pandemic.

Peiris said his team planned to optimize the efficacy
of the new vaccine.

They will explore the new strategy to create a
"universal influenza vaccine" that can fight a range of subtypes of the H5
strain of bird flu virus.

The study, co-authored by scientists from the U.S.
National Institutes of Health, is published on the March issue of the Journal of
Immunology.