West Nile virus vaccine under development

LEIPZIG, Germany, Nov. 4 (UPI) -- German scientists say they are developing a DNA-based West Nile virus vaccine that can also be effective after onset of the disease.

The researchers at the Fraunhofer Institute for Cell Therapy and Immunology in Leipzig said in their vaccine DNA molecules known as plasmids are extracted from the pathogen and are used for inoculation, instead of the whole virus.

"They contain the genetic code for the antigens that stimulate the body to produce antibodies," said Matthias Giese, who is leading the vaccine development. "We can thus replicate the virus's natural infection route without actually triggering the disease."

Such vaccines, he said, are inexpensive and do not require refrigeration, which makes them ideal for use in subtropical and tropical climates. And unlike conventional vaccines, DNA vaccines can be used both prophylactically and therapeutically.

Giese expects the laboratory research to be completed by the end of 2009. After that, at least another three years will be needed for clinical trials and regulatory approval.

Then, he said, it is hoped, the world's first therapeutic West Nile virus vaccine will be ready for market.