An effective vaccine for bird flu?

The words ‘bird flu’ have struck terror into many in the food industry as well as those concerned for wildlife. The H5N1 avian flu virus has become entrenched among birds in much of Asia and parts of Europe, Africa and the Middle East. It rarely infects people but it has killed 243 people out of 385 infected in 15 countries, according to the World Health Organization.

Experts fear the constantly mutating virus could change into a form easily transmitted from person to person, perhaps sweeping the world and killing millions. At least 16 companies are working on vaccines against H5N1, and although it may be too early to claim complete victory, a DNA-based vaccine against bird flu has been developed by Vical Inc. This is a US company based in San Diego who research and develop biopharmaceutical products based on a patented DNA delivery technology. They have previously been involved in developing gene-based treatments for cancer and infectious disease vaccines, and with the bird flu vaccine they are claiming that it can safely stimulate the immune system to levels expected to protect against this disease.

However, their study is a small one, using only 100 volunteers, although 67% 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. This was a Phase I clinical trial, meant to demonstrate the vaccine is safe, and is continuing.

DNA vaccines use bits of genetic material called plasmids. They are meant to generate an immune response against a specific bit of the virus and are designed to last longer than standard vaccines under conditions of heat and cold. If successful, Vical says a DNA-based vaccine could be made in six to eight weeks, compared with four to six months for influenza vaccines made the current way, using bits of the actual virus grown in chicken eggs and this shorter time scale is a tremendous advantage when dealing with a potentially worldwide infectious disease.