Bioterrorists could unleash deadly flu

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Influenza kills an estimated 37,000 Americans yearly, but if the flu virus were to be genetically altered by bioterrorists, as some predict could happen, the death toll could easily reach into the millions, researchers say.

"It definitely could be in the millions ... the imminence of a pandemic is there, whether [the flu virus] is a naturally evolved strain or a man-made strain," said Yuping Deng, an immunologist and associate professor of internal medicine at the Eastern Virginia Medical School (EVMS) in Norfolk.

"The technology of manufacturing a new flu strain is there. I would hope that would not happen, but we need to get prepared," she said.

Richard Drake, director of EVMS's new Scientific Center for Biodefense, agreed. "There would be nothing good about a scenario [in which terrorists] can engineer something we have no defense against, let alone, as we tried to counteract the avian flu," he said.

The World Health Organization predicts between 7 million to 100 million people could die in a global bird flu pandemic, if, through genetic mutation, human-to-human transmission of the virus becomes possible.

Ms. Deng and Mr. Drake are among a team of researchers at EVMS who are striving to bring a stronger medical arsenal against the flu, whether it's the standard strain or an exotic new version fashioned by nature or terrorists. They are working closely with Dr. Stefan Gravenstein, professor of internal medicine and director of EVMS's GlennanCenter for Geriatrics and Gerontology.

Given that people ages 65 and older already account for 90 percent of flu-related deaths in this country, it's certain the elderly would be among the most susceptible if influenza were to become more potent.

To help that vulnerable population, the team has received a two-year, $460,000 federal grant to try and develop a way to strengthen the immune systems of elderly adults so they can fight off the flu more effectively.

The researchers are testing the effectiveness of an experimental nasal flu vaccine that can be produced much faster than is currently possible, since it is grown in cell culture rather than chicken eggs.

In previous research, Ms. Deng found strong evidence that a subset of immune T-cells control the body's level of antibodies.

"You need T-cells to activate B-cells, which produce antibodies," she said. "But T-cell function diminishes with age," so older people produce fewer antibodies to a flu shot than will a younger person.

Ms. Deng points out that the flu vaccine is typically 40 percent to 60 percent less effective in the elderly because of their weakened immunity. In 20 percent to 30 percent of seniors, the flu vaccine does not work at all.

"The goal of our research is to pinpoint the mechanism of the T-cell defect (in the elderly) and find a strategy to restore the effect. ... We need to make a vaccine that's more effective. That's the bottom line," she said.