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Politics : PRESIDENT GEORGE W. BUSH -- Ignore unavailable to you. Want to Upgrade?

To: Henry Niman who wrote (695645)	8/6/2005 9:26:51 PM
From: Hope Praytochange	Respond to of 769670

To Create a Vaccine, a Virus Is Tweaked, Then Replanted By LAWRENCE K. ALTMAN The new vaccine for Avian flu is derived from a strain that Dr. Robert G. Webster helped isolate from a human case in Vietnam. He is an internationally known influenza expert at St. Jude's Children's Research Hospital in Memphis whose work is supported in part by Dr. Fauci's institute. Because the A(H5N1) strain of Avian flu is lethal for chickens and so could not be grown in eggs, Dr. Webster had to use a recently developed technique known as reverse genetics to remove the gene that made the virus deadly. This altered seed virus was used by Sanofi-Pasteur to produce the vaccine in chicken eggs under contract from the government. Dr. Fauci's institute received the first batch of 8,000 doses from Sanofi-Pasteur in the spring. In April, doctors injected the vaccine into 452 healthy volunteers at three centers: The University of Maryland in Baltimore; the University of Rochester in New York; and the University of California, Los Angeles. The recipients received one of four different doses of the vaccine and the results confirmed the scientists' prediction that a larger dose of A(H5N1) virus than used in standard influenza vaccines would be needed to produce the strongest immune responses, Dr. Fauci said. Evidence that the vaccine could be protective came from analysis of 113 of the 452 participants. These findings have been discussed only among the doctors who conducted the studies and the scientists at his institute, Dr. Fauci said. Though the numbers were small, they were enough to show scientifically that the vaccine elicited a strong immune reaction - a critical point of the study. The only way scientists can prove the effectiveness of the vaccine is if an epidemic of the A(H5N1) strain occurs among people. Ethics prohibit deliberately infecting people for experimental purposes, in part because that could lead to the very pandemic scientists are trying to prevent. Under such circumstances, scientists must show that as the dose of the vaccine is progressively increased, the immune response increases proportionately. Dr. Fauci said he was "encouraged" about the findings because "many other experimental vaccines have produced flat dose-response curves," meaning that the vaccines were ineffective because they did not stimulate the necessary immune response. "What confirms the fact that you have an immunologically potent vaccine is when you get a good dose-response curve, and unquestionably we got one with this vaccine," he said.