Researchers hope to develop effective vaccines against the avian flu, which broke out on two Delaware farms in 2004. (Photo courtesy of the USDA)

By Jacqueline Ruttimann
Capital News Service
Wednesday, Sept. 28, 2005

WASHINGTON - Gaithersburg-based MedImmune Inc. will join forces with the National Institute of Allergy and Infectious Diseases in developing a series of vaccines against the avian flu virus, Health and Human Services Secretary Mike Leavitt announced Wednesday.

"The threat of pandemic flu is an urgent health challenge," Leavitt said on The Diane Rehm Show on WAMU. "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."

MedImmune, one of the nation's four vaccination providers for the common flu, will use its nasal spray vaccine FluMist in the vaccine creation process.

NIAID and MedImmune plan to develop at least one vaccine for each of the 16 variations of a surface protein -- known as hemagglutinin -- found on the avian flu virus, including the one for the H5N1 virus that is spreading throughout Asia, Kazakhstan and Russia and that scientists fear may develop into a pandemic.

The H5N1 strain of the avian flu virus, found in wild migratory birds throughout Southeast Asia and parts of Russia, has infected and killed numerous species, including domestic poultry, pigs and, sporadically, people. According to a Sept. 22, 2005, World Health Organization report there have been 115 confirmed human cases of avian flu and 59 deaths.

Although the virus still is transmitted from animal to animal and animal to human, worldwide health officials, such as Centers for Disease Control and Prevention Director Dr. Julie L. Gerberding, say that it is "highly likely" that the virus will mutate into a form that can spread from human to human. That change in transmission could cause a worldwide pandemic.

The combination of the avian flu virus with a human influenza virus was the cause of two previous worldwide pandemics, the Asian Flu in 1957 and the Hong Kong Flu in 1968, both of which spread worldwide within one year of being detected, according to the CDC Web site.

CDC modeling studies estimate that in the absence of any control measures such as vaccines or antiviral drugs, a "medium-level" U.S. pandemic would affect 15 to 35 percent of the population, cause 89,000 to 207,000 deaths and 314,000 and 734,000 hospitalizations.

On the same program, Leavitt said a pandemic could spread much like a forest fire, and stressed that vigilance is necessary for worldwide health officials to curb its onset.

"If we see it when it's just a spark we can put it out," said Leavitt, indicating that preventive measures such as quarantines and vaccines would be employed. He also said a "substantial investment" would be needed in terms of expanding the production capabilities of vaccine manufacturers, ensuring worldwide collaboration, creating tools that would accurately and quickly predict the first U.S. avian flu case and purchasing a national stockpile of drugs.

The strategic national stockpile currently has enough Tamiflu, the only antiviral effectively shown to treat influenza viral strains similar to the avian flu, Gerberding said to Congress in May, to cover 8.3 percent of the total U.S. population. There is enough of another antiviral, rimantadine, to cover about 17 percent of the population, however influenza viruses quickly obtaining resistance to it.

Collaboration between public and private health institutions that manufacture vaccines is a step in the right direction, said Dr. James Campbell, principle investigator at the University of Maryland School of Medicine Center for Vaccine Development. Campbell is testing one of three NIAID-sponsored human clinical trials. He is using a vaccine derived from the injectable vaccine Fluzone from Sanofi Pasteur.

"I think it's a great idea," said Campbell. "It's a hope that we will have multiple companies and multiple institutions working toward a pandemic vaccine."