Vical Inc. has announced that preliminary clinical trial data demonstrate that DNA vaccines can safely achieve significant immune responses against H5N1 pandemic influenza in humans.

DNA vaccines are fundamentally different from conventional vaccines because they do not contain any part of the virus itself, and may offer compelling advantages in response to a pandemic outbreak because of significantly reduced development and manufacturing times.

The company said in a study of 100 volunteers, 67 per cent of the patients receiving the higher dose had immune responses that could protect against infection with the H5N1 avian flu virus, with no serious adverse reactions after two injections. The Phase I clinical trial currently underway is hoped to demonstrate that the vaccine is safe.