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NIAID, MedImmune Agree To Develop Avian Flu Vaccines
"The threat of pandemic flu is an urgent health challenge," Secretary Leavitt said. "This agreement will help speed the process of developing vaccines we will need to fight an outbreak if the avian flu starts to spread rapidly through the human population."
Kanta Subbarao, M.D. M.P.H, and Brian Murphy, M.D., of NIAID's Laboratory of Infectious Diseases will lead NIAID's part in this collaboration. The agreement specifies that the scientists will add selected genes from avian flu viruses with pandemic potential into a weakened human flu virus to create several attenuated, live virus vaccines candidates.
"Our agreement with MedImmune coordinates public and private resources and brings a deeper pool of talent to bear on the urgent need for vaccines to combat the threat of an influenza pandemic," said NIAID director Anthony S. Fauci, M.D. "It is an example of the many productive public-private partnerships upon which we depend in our quest to develop vaccines, drugs and diagnostics for myriad infectious disease threats."
Infectious disease experts worry that avian influenza viruses, which until recently have rarely infected people, could trigger a devastating global flu outbreak. The H5N1 avian influenza is especially troubling as it has spread rapidly among birds and other animals in Asia since late 2003, and more recently has been found in birds in Russia and Kazakhstan. According to the World Health Organization, of the 115 people in four Asian countries who have been infected with H5N1 from late 2003 through 2005, 59 have died. While this virus currently is not known to spread efficiently from person to person, it could trigger a human influenza pandemic if it acquires that ability.
NIAID and MedImmune will develop at least one vaccine for each of the 16 variations of a key influenza surface protein known as hemagglutinin (represented by the letter "H" in the names of influenza strains, such as H5N1). NIAID and MedImmune will develop vaccines for the highest priority hemagglutinin subtypes first. The researchers say it will take years to systematically develop vaccines for all the hemagglutinin subtypes. Having effective vaccines against all subtypes will help us prepare for influenza pandemics in the future, explains NIAID's Dr. Subbarao.
Human influenza viruses that have circulated in the last century contain one of three possible hemagglutinin proteins (H1, H2 and H3); potential pandemic viruses contain one of the others to which humans have never been exposed. Not having any prior exposure to the hemagglutinin in H5N1 avian influenza virus currently spreading in Asia, the human immune system is unprepared to fight it. For that reason, developing an H5N1 vaccine is a high priority for the NIAID/MedImmune collaboration.
Under the agreement, NIAID and MedImmune will use methods such as reverse genetics and classical reassortment to place hemagglutinin genes with pandemic potential into an attenuated human flu virus. Reverse genetics is a laboratory method by which researchers can custom make a flu vaccine by assembling genes that code for the desired features. Reassortment is the swapping and mixing of gene segments between two different viral strains inside a chicken cell to create a new vaccine.
The NIAID/MedImmune agreement builds on research pioneered by NIAID's Dr. Murphy beginning in the 1970s. Working with the developer of the attenuated influenza virus -- John Maassab, Ph.D., of the University of Michigan School of Public Health -- Dr. Murphy and colleagues created a flu vaccine from a live flu virus weakened so that it would not cause disease. As an extra measure of safety, the researchers grew the live virus vaccine in progressively colder temperatures to prevent it from spreading beyond the relatively cool upper respiratory tract. This "cold-adapted" virus is proprietary to MedImmune and is the basis of MedImmune's FluMist® flu vaccine, also a product of a public-private partnership between NIAID and MedImmune. The researchers will use the same cold-adapted virus as the backbone for the pandemic influenza vaccines.
NIAID and MedImmune will generate many of the vaccines in NIAID's Bethesda, Md., labs. Both NIAID and MedImmune will initially conduct laboratory studies of the vaccines. MedImmune then will manufacture the vaccines for human clinical trials, which NIAID will run through a contract facility, pending Food and Drug Administration approval. These studies will assess vaccine safety and immunogenicity.
NIAID is a component of the National Institutes of Health, an agency of the U.S. Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose and treat infectious diseases such as HIV/AIDS and other sexually transmitted infections, influenza, tuberculosis, malaria and illness from potential agents of bioterrorism. NIAID also supports research on transplantation and immune-related illnesses, including autoimmune disorders, asthma and allergies.
Source: National Institute of Allergy and Infectious Diseases