I was watching a television show yesterday and the premise of the episode was that a terrorist group had broken into an old abandoned USPHS lab and stole samples of the original strain to use as a biological weapon. It got me thinking, is that particular version of the flu virus still particularly dangerous? I know H1N1 strains are still dangerous and have been responsible for a few more pandemics since the Spanish flu but it seems that we should have some resistance to the strain that caused that pandemic. My reasoning is that it never went away. We didn’t beat the Spanish flu with vaccines and health measures rather it just killed pretty much everyone it could and we eventually developed a level of resistance to it that made its threat more in line with the seasonal flu. If my reasoning is correct then the terrorists releasing the virus in the subway shouldn’t be any more dangerous that someone with the flu taking the subway to work which is a common occurrence during flu season.

So, how does it actually work? Did we develop a resistance like I think or would a release of the original strain start a new pandemic?