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.