You know as I was writng that I was just thinking "I'm not going to get away with this one." *g* Although the possibility that occurred to me was that it might have been a suicide nuke rather than a biological weapon. It's a TV convention I suppose that stories accquire temporary immunity to recently used plot points. And why is it only on TV that vaccines are something you give people to cure diseases after they get them? I mean surely even writers know you don't treat measles with MMR injections.