Narrator: Drug designers are going after the flu. This is Science Today. For most of us, the flu is merely a nuisance. But for some people it's deadly -- and as biochemist Andrew McAmmon of the University of California, San Diego points out, sometimes a really virulent strain pops up, like the Spanish influenza that killed 30 million people at the end of World War I.

McAmmon: And there's always the chance that the vaccine that's been prepared for the coming flu season may not be quite the right one to deal with a sudden emergent strain like that.

Narrator: But now it's possible to design a drug that nips the flu in the bud. The flu virus has a key enzyme with a molecule-sized pocket. Researchers are working on a drug that fits that pocket and in doing so, blocks the action of the virus, making it less infectious.

McAmmon: It's very much like hobbling a horse or throwing a monkey wrench in a mechanism of some kind. This is very much what we try to do with our drug discovery work.

Narrator: McAmmon says the hope is that the new compound will work for many different flu strains. For Science Today, I'm Steve Tokar.