But getting companies to invest in vaccines for less immediate threats, such as smallpox or other bioterror agents, isn't so easy: There is usually no market unless the threat materializes. Even tougher is trying to anticipate and defend against infectious agents that now exist only in a terrorist's grim imaginings.
That's why Uncle Sam is whipping out his checkbook. Already, Washington is planning to spend more than $1 billion on vaccines for smallpox and anthrax. And taxpayers are helping to fund vaccines for West Nile virus and other less familiar pathogens. "The government has to buy and stockpile vaccines and drugs against nonexisting diseases," says Ronald M. Atlas, co-chair of the American Society for Microbiology's biological weapons task force.
Yet even a vaccine stockpile would be of limited use against the worst nightmare: a virulent new agent cooked up by a terrorist. The world got a small but nasty taste of how easy this can be when, in 2001, Australian scientists inadvertently created a superbug. After adding a gene to generally benign mousepox virus to try to create a mouse contraceptive, the engineered virus killed every mouse it struck.
In some cases, vaccines might slow an epidemic of such a superbug. After all, says Dr. Gary Nabel, director of the Vaccine Research Center at the National Institutes of Health, it's easier for terrorists to create anthrax that shrugs off antibiotics like Cipro than to engineer a strain that overcomes an immune system primed with a vaccine.
Still, should terrorists create something too nasty for existing vaccines to fight, researchers have other weapons. In a project funded by the Defense Advanced Research Projects Agency (DARPA), Stephen A. Johnston, a biochemist at the University of Texas Southwestern Medical Center, has created a fast way to crank out vaccines against new biothreats.
The idea is to quickly test cocktails of genes from a bacterium or virus to see which of the proteins made by the genes can stimulate immune responses in animals. DARPA managers figure the method may make it possible to find vaccine candidates in a few days. The problem, however, is that proving the vaccines are safe and effective--and making enough to protect a city or country--would take months, at best.
To really protect the country, it's not enough for the government to store vaccines against known threats, scientists say. We also must anticipate what microbes our enemies may try to create. Scientists are now mobilizing to meet that challenge. By John Carey in Washington