Vical Inc., a San Diego-based company, announced today that researchers have made a DNA-based vaccine that can safely fuel the immune system to levels expected to protect against avian flu.
Researchers have been worried that if there is a global outbreak of bird flu, existing anti-flu remedies could fail to be effective because some strains of the virus have already developed a resistance to them.
Vical said a DNA-based vaccine is preferable because it could be made in six-to-eight weeks, compared with four-to-six months for flu vaccines made the traditional way, using pieces of the actual virus grown in chicken eggs.
DNA vaccines, on the other hand, use bits of genetic material called plasmids that can trigger an immune response against a specific part of the virus. Plus, they’re designed to hold up better than traditional vaccines under extreme heat or cold, Vical said.
In a study of 100 volunteers, 67 patients receiving the trial dose had immune responses that could protect against bird-flu. No serious adverse reactions were observed after two injections, company officials said in a statement about early trial results. The complete Phase I clinical trial, to demonstrate whether the vaccine is safe, is still underway.
The bird flu virus — technically called avian virus H5N1 — has been found in birds in Asia, 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 with the organization worry that the frequently mutating virus could morph into a form that could be easily transmitted between people.
At least 16 companies are working on bird-flu vaccines, the organization said. It’s unclear which particular vaccines would work against whatever strain might eventually cause a pandemic, but the ability to make a vaccine in weeks instead of months could be an advantage.