Researchers are reporting preliminary success with a vaccine against a possible "bird flu" pandemic, using a process they say could deliver the product in half the time required by older technology.
The milestone, experts said, also offers hope for speedier production of a vaccine against seasonal flu, potentially eliminating contamination problems and shortages that have cropped up in recent years.
Reporting today in a leading medical journal, scientists with Baxter International Inc. said their avian flu vaccine - which dispenses with the cumbersome process of growing vaccine in chicken eggs - was safe and triggered an immune response.
"This of course changes the whole game," Dr. Hartmut J. Ehrlich, a research and development chief for Baxter, said of the results. "We have shown that influenza vaccines can be produced in substrates different from chicken eggs."
As with any flu vaccine, it remains to be seen whether the vaccine would protect people in the face of a true pandemic. The vaccine has protected animals in earlier studies, but ethical constraints prevent researchers from exposing immunized humans to the virus to see what happens.
The Euro-Asian trial, described in today's New England Journal of Medicine, was conducted among 284 human subjects in Austria and Singapore and was designed to help Baxter win regulatory approval from European authorities. A parallel study involving the same vaccine has been under way in the United States to meet requirements of the Food and Drug Administration.
Although the U.S. trial results have not been published, "I can tell you the immune response was very, very similar," Ehrlich said in an interview. With slight differences, the two trials showed that the vaccine triggered an immune response in about 70 percent of volunteers.
It could take four or five more years of testing and data analysis to produce a vaccine ready for FDA review, Baxter officials said.
Rather than growing each vaccine in a fertilized egg, scientists produced them in large vats containing cell cultures. The process takes about 12 weeks, compared to the nearly half-year timetable for egg-based manufacture.
"If you can use a cell culture, it's like brewing beer," said Dr. Wilbur H. Chen, an assistant professor with the University of Maryland School of Medicine's Center for Vaccine Development. "You have a big vat full of cell culture. You stick virus in it and grow it."
