Vaccines are considered a key defense should the H5N1 avian flu virus that has spread among birds in Asia, Europe and parts of Africa evolve into a form easily transmitted among people, sparking a pandemic.
In this respect, the companies are trying to prepare vaccines by injecting the antigen or part of the virus in bacteria, insect cells or plant cells, as an alternative to the unwieldy, egg-based system that takes months to turn out flu vaccine.
Though the scientists fear that the new approaches might not reach the market for years if an avian flu pandemic erupted in the near future.
