Quickie Bird Flu Vaccine Created

WASHINGTON -- A new bird flu vaccine made using cleaner technology took just a month to make and completely protected chickens from the deadly H5N1 virus, U.S. researchers reported Thursday.

The genetically engineered vaccine appears to fulfill the promise of modern influenza vaccine technology being pushed by public health experts who want to improve the slow, old-fashioned methods now used to fight the flu.

The team at the University of Pittsburgh is now putting together a plan to test the vaccine in humans.

"This is a very potent vaccine," Dr. Andrea Gambotto of the University of Pittsburgh School of Medicine, who led the study, said in a phone interview. "It took roughly about 30 days to make the vaccine from when we received the sequence information from (the Centers for Disease Control and Prevention) in Atlanta."

Current influenza vaccines for both chickens and humans take months to make and are grown in chicken eggs. Production is uncertain and the vaccines do not provide perfect protection.

Experts agree the way to go is cell-based production -- growing the vaccine in batches of human cells grown in the lab instead of in eggs.

Several shortages of vaccine for the seasonal flu made this need even more dire. But the spread of the H5N1 virus has made the need for better vaccine technology urgent.

H5N1 affects mostly birds but it has infected more than 150 people and killed more than 80 of them. Experts fear it could acquire the ability to pass from person to person, sparking a pandemic that could kill millions around the globe.

Because no one knows just how H5N1 will mutate, experts say it will not be possible to start making a vaccine against it until the pandemic strain emerges. Gambotto hopes his team's approach will provide a way to start making such a vaccine quickly.

They did not use the actual H5N1 virus -- just genetic sequence data from the Centers for Disease Control and Prevention. "We have the technique to go from an e-mail to a virus," Gambotto said. They artificially generated the DNA coding for the hemagglutinin gene -- which controls a protein found on the surface of all influenza viruses and provides the "H" in a virus' name.

"We generated the portion that we think was important for immunity," Gambotto said. "We never manipulated the actual H5N1 virus ourselves, so it is safe to generate this kind of vaccine."

They then spliced this artificial DNA into a human adenovirus, a common cold virus. Tests in mice and chickens showed it provided partial protection when given nasally, and 100 percent protection against H5N1 when injected, they report in the Feb. 15 issue of the Journal of Virology. And it produced what is known as a dual immunological response -- the body generated both antibodies to neutralize the virus, and T-cells, a kind of immune cell that also attacks viruses.

"That means there is a lot of chance of getting cross-reactivity," Gambotto said. In other words, the vaccine may work against mutated versions of the flu virus, something current vaccines cannot do. This is why the flu vaccine now must be reformulated every year.

Gambotto also hopes the nasal vaccine might work better in people than it did in animals, because the vaccine uses a live human adenovirus.

His team is working with the U.S. Food and Drug Administration to get approval to move ahead with human trials.

The University has the technology to make and test its own vaccines. "Eventually we will need to partner with a company for large-scale production of vaccine," Gambotto said.