Trials conducted at the St. Jude Children's Research Hospital showed that Vical's DNA vaccine candidate against avian flu showed 100% efficacy in mice and ferrets infected with a highly virulent strain of the H5N1 Avian influenza virus (isolated from Vietnam). In contrast to conventional vaccines using chiken eggs or cell culture for production, Vical's DNA vaccine is produced via fermentation carried out by bacteria engineered to produce the necessary proteins to make up a vaccine. This novel method of vaccine production allows vaccine to be produced in large quantities over a short period of time.

The vaccine tested was composed of two highly-conserved influenza virus proteins, nucleoprotein (NP) and matrix protein (M2), as well as the H5 avian influenza virus surface protein. Tests using a vaccine without the surface protein in addition provided high levels of protection against multiple human flu strains, suggesting an advantage in adressing a potential flu pandemic that may arise.

"A vaccine that provides cross-protection against more than one strain of flu is important for addressing a pandemic flu threat because it is likely that the H5N1 virus could mutate before it becomes transmissible from human to human," said Dr. Webby. "The current data show that this vaccine has the potential to achieve cross-protection because it targets two conserved flu virus proteins as well as H5."

Details of the study are provided in Vical's and St. Jude's press releases. A webcast replay is also available to interested parties at Vical's webcast center.

Following this news release, Vical's shares rose 31% yesterday.