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Bird flu vaccines: Challenges of preventing a pandemic
From MayoClinic.com
Special to CNN.com
Researchers are working hard to create a vaccine that can prevent bird flu. The process currently used to create, produce and distribute traditional seasonal flu vaccine is slow, and it won't be adequate if a bird flu pandemic occurs. Gregory Poland, M.D., director of the Vaccine Research Group at Mayo Clinic, Rochester, Minn., explains what options exist. How close are we to having an effective vaccine for bird flu?Several companies have initiatives to make a bird flu vaccine. These are all in development and testing, however, and not likely to be available soon. Why is it not possible to rapidly develop new vaccines against newly formed flu viruses?The problem with the vaccines in development is that they use 50-plus-year-old technology in which the vaccine is produced using chicken eggs. This process is slow. If a highly contagious bird flu strain were identified today, it would take a minimum of four to six months to make and distribute the first doses of a vaccine against it. New technologies, however, are on the horizon. Primary among these is one that uses mammalian cells instead of eggs. Scientists would grow and store cells in large quantities so that they'd be ready and waiting. As soon as a flu strain becomes apparent, scientists could infect those cell cultures, then quickly harvest the resulting influenza proteins and distribute them as a human vaccine. Given the challenges of producing a bird flu vaccine in large quantities, what can we expect in terms of vaccine protection?I'm hopeful that we'll have a larger stockpile of vaccine in the next one to two years. In the meantime, large quantities of a pandemic influenza vaccine are not available. If a pandemic occurred right now, the best we could do to deal with it would be to enact a quarantine to contain spread of the virus — if the outbreak was limited to a geographical area — and to use antiviral medications and what little vaccine is currently available. October 02, 2006 |