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Last Updated

23 Sep 2003

Source: Newsday, September 23, 2003

The Flu Factor In Bioterrorism

By Delthia Ricks, STAFF WRITER

The very mention of the words anthrax or smallpox can immediately summon the specter of bioterror. Rarely, though, does mention of the influenza virus inspire thoughts of a weapon of mass destruction.

Scientists at Stanford University, however, theorize that not only could the virus be used for malicious intent, but the pathogen's natural ability for rapid mutation and spread might make it an ideal weapon of terror.

Already scientists are nearing completion on replicating the genetic sequence of the virus that caused the horrific 1918 influenza pandemic. With such knowledge in the wrong hands, experts say, influenza could prove more deadly than anthrax, smallpox or even bubonic plague.

To study how such terrorism might occur - and be thwarted through a new generation of vaccines - a team of Stanford researchers has received a $15-million grant from the National Institute of Allergy and Infectious Diseases. The upcoming study is part of an $85-million project overseen by the institute to investigate microbial agents that could, under certain circumstances, be transmuted into weapons of terror.

Two Stanford microbiology and immunology experts, Dr. Ann Arvin and Dr. Harry S. Greenberg, are leading the new look into the ancient foe. Their plan is to understand how terrorism might occur by developing a more intimate knowledge of the flu virus.

"We've known for decades that the influenza virus is capable of mutation," said Arvin, a professor of pediatrics, microbiology and immunology. "All of us get the flu periodically, and that's not because we've become more susceptible but because the virus has changed.

"Every few years the virus mutates and infects people who've been infected in the past" with somewhat different strains, she said. "It's a virus that is subject to change because that's how it survives."

Because the virus constantly mutates, vaccines must be continually updated. For the most part, though, such strains are not global killers, and most who catch the flu don't face an imminent threat of death.

Arvin and Greenberg hope to study the immunity that develops following flu vaccination. How vaccines protect the respiratory tract is poorly understood, Arvin said. The researchers' aim is to investigate what is known about immunity and to develop a vaccine that could be used to protect people in the event of an outbreak caused by terrorism.

"That is a very important part of our work, to understand how to design a vaccine, to know the ultimate kind of vaccine to use," Arvin said. "If we could understand how to provide immunity against those proteins of the virus that don't tend to mutate, it would be possible to think about a different vaccine design."

Such a vaccine would not be anything like the immunizations used to prevent seasonal exposure to influenza viruses. To protect against influenza caused by bioterror, Arvin said, a vaccine would have to act quickly in the respiratory tract, in a matter of days.

Current flu vaccines are administered in October and November to provide immunity that takes weeks to develop. By the time flu viruses flare in January, vaccinated people usually have mounted a sufficient supply of antibodies to fight infection. Flu viruses usually remain active through March.

The real lessons about what influenza might do in an act of bioterrism, the researchers say, can be learned from past pandemics: Three times in the last century influenza played a nasty trick, transforming into a virus to which no one had immunity. Highly contagious and easily aerosolized, the infections spread among continents through a chain of coughing and sneezing. The 20th century's three influenza pandemics - the 1918 global outbreak also known as the Spanish flu, the 1957 Asian flu and the 1968 Hong Kong flu - killed millions.

But lessons also can be learned from limited outbreaks with unusual strains that carried the threat of broader and deadlier disease. What stopped such viral menaces as the 1976 swine flu, the 1977 Russian flu or the avian flu scare six years ago in China?

"The background for all of this," Arvin said of her study, "is simply knowing what flu can do in and of itself. And as we understand this virus better, it is conceivable to produce vaccines to protect the population.

"We hope we will learn information that is relevant," she added, "whether it is about a natural pandemic or a deliberate effort."