In an effort to thwart an influenza strain that has jumped from bird to man, Chiron Corp. won a government contract to produce a vaccine that could keep the population safe from a pandemic.

The National Institutes of Allergy and Infectious Diseases (NIAID) signed Emeryville, Calif.-based Chiron to find an effective way of protecting people from a strain of avian influenza that recently surfaced in China and the Far East, killing more than 20 humans and resulting in the cull of poultry throughout the region. The NIAID granted a similar contract on Thursday to Aventis SA, of Strasbourg, France.

"Since the outbreak everyone was very relieved that it was contained in the Far East," said Rob Budge, divisional vice president of corporate communications at Oxford, UK-based Chiron Vaccines, a division of Chiron. "There's been a number of national and international bodies looking at pandemic preparedness."

While Chiron already has produced vaccines against other types of avian influenza, including a strain that circulated in the Hong Kong region in 1997, killing several people, the company will focus on the H5N1 influenza strain under the new contract. Chiron published a couple of papers after developing the vaccine for the last strain. That research will help the company in developing a vaccine for the newest strain, Budge said.

"It pieces together the jigsaw as to how you actually go about doing these things," he told BioWorld Today.

Chiron Vaccines and Aventis each intend to produce 8,000 doses of the H5N1 vaccine. The NIAID would conduct all clinical studies evaluating the vaccines for safety and immunogenicity at two different dose levels. Chiron plans to produce the vaccine at its Liverpool, UK, manufacturing facility, using the same process as it does for its Fluvirin influenza vaccine. Sales of Fluvirin in 2003 were $219 million.

Chiron will use reverse genetics to make the vaccine from seed virus. Aventis said it intends to produce its version of the vaccine at the Aventis Pasteur facility in Swiftwater, Pa. Financial terms of the contracts were not disclosed.

Avian influenza outbreaks occurred last winter, causing concern over the threat of widespread infection. According to figures from the Centers for Disease Control and Prevention in Atlanta, influenza results in 36,000 U.S. deaths each year, mostly of people who are chronically ill or seniors. But a pandemic could be far worse, resulting in 1 million to 2.3 million hospitalizations and 280,000 to 650,000 deaths in industrialized nations, the World Health Organization said.

"What you get with a pandemic is a strain that emerges in which people don't have immunity. It's a new strain that people haven't encountered," Budge said.

While avian influenza - or "bird flu" - has not infected humans in the past, it has transmitted to people in recent years. If an avian strain recombines with a human influenza strain, it would become more transmissible among humans.

The World Health Organization estimates that the avian influenza outbreak last winter in Southeast Asia resulted in 34 human cases, in which 23 people died. It also resulted in the deaths of 100 million birds either from the disease itself or the subsequent cull.

Pandemics occur every so often around the world when a new strain develops faster than people can build up immunity. In 1918-1919 the Spanish flu killed between 20 million and 50 million people.

"We do expect another pandemic at some point," Budge said. "Nobody knows when, but we did have three last century."

Chiron's stock (NASDAQ:CHIR) dropped 17 cents on Thursday, to close at $44.92.