Bird flu vaccine shows promise16th June 2008
A clinical trial by corporate researchers in the United States says a new bird flu vaccine made using monkey cells instead of chicken eggs appears to be safe and effective.
Baxter International said its vaccine against H5N1 avian influenza underwent the phase I/II safety trial involving more than 250 people, and produced a strong immune response in people who received two doses.
The vaccine, called Celvapan, is made in Bohumil in the Czech Republic. During the trial, researchers measured antibodies in volunteers in Austria and Singapore, saying those vaccinated showed an immune response similar to the body's defense against a natural virus infection.
In a report published in the New England Journal of Medicine, Baxter scientists said the vaccine was the first bird flu vaccine to be made using cells in a lab dish instead of chicken eggs.
H5N1 kills chickens rapidly, and the right type of chicken eggs are difficult to obtain.
But they said that adding an immune system booster called an adjuvant did not make the vaccine work any better.
The team, led by Hartmut Ehrlich, vice president of global research and development for Baxter's BioScience business and colleagues, found the lack of booster effect was puzzling as adjuvants have helped other bird flu vaccines.
Apart from Baxter, another 15 companies are currently known to be developing H5N1 avian influenza vaccines.
So far, there have been 382 human cases of the H5N1 bird flu virus, mostly in south-east Asia, of which 241 have died in 15 countries.
Most cases have been in poultry workers and at present the virus cannot pass that easily from human to human, but if that changes it will pose a potential threat across the world. Experts fear a pandemic strain could emerge, killing millions of people.
While there is no guarantee that the vaccines currently in development will offer protection against an emerging strain of pandemic flu, world health experts say it is better to be prepared, especially as existing vaccine manufacturing capacity could be quickly converted in the event of pandemic.
Fertilised chicken eggs have been used until now to produce all influenza vaccines.
But they are available only seasonally, creating a time constraint in the manufacture of yearly vaccine. This could affect the world's ability to prepare for a pandemic, experts say.
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Title: Bird flu vaccine shows promise
Author: Luisetta Mudie
Article Id: 7105
Date Added: 16th Jun 2008