Making a better flu shot

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SAN FRANCISCO -- The flu vaccine-making system that serves as the best available protection against a pandemic relies on millions of chicken eggs, takes nine months to produce each year's flu shots and has changed little since the 18th century.

This creaky system poses a big problem if a new, deadly strain emerges once the annual and inflexible production process begins.

Several biotechnology companies are working on a quicker way of making a flu vaccine that they hope can replace one that requires people to be inoculated with the entire influenza virus. Their technique is to extract just a few genes from the virus and inject it into people.

The nascent technology, called DNA vaccines, is a form of gene therapy that proponents argue is the best way to overhaul a 50-year-old vaccine manufacturing system.

The gene jockeys touting DNA vaccines say they are getting close to making vaccines with less effort. They say they can soon produce flu vaccines in less than three months that would inject people with key bits of a flu's DNA.

If a flu were to mutate into something unexpected, researchers say, they can simply grab a gene from the new strain and gin up more vaccine. Best of all, they argue, their technology knocks drug makers out of the chicken-wrangling business.

"We are badly in need of flexible vaccines programs," said Erik Henchal, a former commander of the U.S. Army Medical Research Institute of Infectious Diseases.

Mr. Henchal said the current production system requires researchers to handle live influenza viruses, a dangerous procedure that DNA vaccines promise to eliminate if successful.

DNA vaccines were introduced about 10 years ago as prospective treatments for diseases from AIDS to cancer. They worked great in mice, but largely failed to work in humans because the injected genes did not find their way into the cells.

Vijay Samant, chief executive of Vical Inc. in San Diego, said those initial problems have been overcome and that his company is testing DNA vaccines in cancer and AIDS patients to battle those diseases.

Canadian fish farmers are using the firm's technology to inoculate salmon against a deadly virus that makes them bleed from their gills.

The company PowderMed overcame the problem of getting the flu's DNA to cells that need to be tricked into thinking the body has been infected with flu by coating the flu's genetic material with microscopic gold particles and shooting it into skin cells at the speed of sound, said PowderMed's chief scientist, Dr. John Beadle.

"I think people are looking at older and more established technology as the safe bet right now," Dr. Beadle said. "And that this stuff is too far out and risky."