Vaccine makers, including an AstraZeneca subsidiary, are gearing up to produce vaccines to protect against a global outbreak of swine flu.
 
But if health authorities direct manufacturers to produce the vaccine, the doses won't be available until months from now. And if swine flu turns out to be less severe than its seasonal cousin, it could deprive millions of people of a vaccine they need each year.
 
That's because drugmakers like Sanofi-Aventis, the world's biggest vaccine maker, and GlaxoSmithKline don't have the capacity to produce vaccines against several types of flu at the same time.
 
"That will be a very difficult choice," Sanofi Chief Executive Chris Viehbacher said at a news conference Wednesday. Sanofi's Sanofi-Pasteur U.S. vaccine unit is headquartered in Swiftwater, Pa. "Clearly, if you make a swine flu vaccine and the pandemic doesn't actually occur, we could end up with no seasonal flu vaccine."
 
The World Health Organization raised its pandemic alert for swine flu to the second-highest level Wednesday, although authorities have not yet directed manufacturers to pursue a vaccine for the new strain. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Wednesday that a vaccine for swine flu may be tested in people within "a couple of months."
 
Among the companies researching a potential vaccine is Gaithersburg, Md.-based MedImmune, an independent subsidiary of drug maker AstraZeneca that produces the FluMist vaccine.
 
FluMist is unique among flu vaccines in that it uses a live, weakened influenza virus, administered through a nasal spray. Other vaccines use killed viruses that are injected.
 
George Kemble, vice president of research and development for MedImmune, said company researchers are working with swine flu virus provided by federal health authorities to isolate the genes that provoke a response from the human immune system.
 
Using an approach called reverse genetics, MedImmune scientists would combine the swine flu antigens with a weakened virus that's safe enough for use in a nasal spray. Kemble said the full production process probably would take about six months.
 
"Obviously, with the events around us, we're trying to accelerate that as much as we can, but there are finite limits," Kemble said.
 
Kemble said he thinks it is likely health authorities will ask vaccine makers to produce a swine flu vaccine. MedImmune, which distributed about 7 million doses of FluMist last year, is in the process of making the raw materials for its yearly vaccines for the 2009-2010 flu season.
 
That production would probably be finished by the time MedImmune is ready to produce material for swine flu vaccine, Kemble said. But, he said, the process of finishing, packaging and distributing both the seasonal and swine flu vaccine doses could overwhelm the manufacturers' capacity.
 
"That's where the struggle will come," he said.
 
The dilemma underlines concerns about the current methods of vaccine production, which involves growing viruses in chicken eggs. Researchers are exploring a number of alternative methods of vaccine production that could provide a faster response time.
 
The Fraunhofer Center for Molecular Biotechnology in Newark and its private-sector partner, iBioPharma, are developing a process to grow material for vaccines in tobacco plants. 
 
Fraunhofer Executive Director Vidadi Yusibov said he is hopeful the nonprofit research group could play a role in the swine flu response.
 
"We have a technology that has great value for situations like this," Yusibov said.
 
Yusibov was reached Wednesday at a conference in France. The topic, coincidentally, was the development of flu vaccines, and Yusibov said swine flu was the subject everyone was discussing.
 
"This is just another proof that a virus may come out of left field," Yusibov said. "It shows us that we need to be prepared."