Avian Flu Vaccine in Development for Deadly Asian Strain

BETHESDA, Maryland, May 28, 2004 (ENS) - The National Institute of Allergy and Infectious Diseases (NIAID) is giving two U.S. companies contracts to work on development of an investigational vaccine to protect against H5N1, the avian influenza flu strain that broke out in Asia in 2004, causing 23 human deaths and the destruction of hundreds of millions of birds.

The contracts were awarded to Aventis Pasteur Inc. of Swiftwater, Pennsylvania, and to Chiron Corporation of Emeryville, California. Both companies already manufacture inactivated influenza virus vaccines that are licensed for use during annual influenza seasons.

Though the H5N1 virus passed through bird flocks rapidly, it did not pass from human-to humans with ease, so widespread disease amongst Asian populations did not occur

Still, international health officials fear that the H5N1 virus could mutate into a form that might spread among humans with ease, causing a serious pandemic. Occasionally through history, influenza epidemics have swept the world, taking millions of human lives.

The 2004 experience "underscores the national and international imperative to develop new and improved medical tools to prepare for the threat of pandemic influenza," said Anthony Fauci, NIAID director on Thursday. NIAID is a component of the National Institutes of Health, an agency of the U.S. Department of Health and Human Services.

"Vaccines are key to preparing for the public health emergency that pandemic influenza would entail," he said.

To develop their inactivated vaccines, the two companies will use a strain of H5N1 avian influenza taken from a Vietnamese patient in February.

With approval from the U.S. Food and Drug Administration, the investigational vaccines will then be tested for safety and immunogenicity in Phase I and Phase II clinical trials. These trials, to be conducted by NIAID's Vaccine and Treatment Evaluation Units (VTEUs), will study the vaccine in healthy adults first with subsequent studies planned in children and the elderly.

Aventis Pasteur and Chiron will each produce between 8,000 and 10,000 doses of the investigational vaccine made through established techniques in which the virus is grown in eggs and then inactivated and further purified before being formulated into vaccines. The use of established techniques to develop the investigational vaccines will help to promote rapid licensing of commercial vaccines in the event of a pandemic outbreak.

Until 1997, avian influenza had never been known to directly infect humans, but that year an outbreak of avian influenza type H5N1 infected 18 people in Hong Kong, six of whom died.