I don't know the answer to that question. 1-3 days would be my stab-in-the-dark guess. Part of the problem is that the efficacy of any post-attack treatment, whether it be a vaccine, an antitoxin, or an antibiotic, is going to drop off the longer after the attack it is given. That means that, after an attack, everyone is going to be very conscious that it's a race against time, and a race against the other fellow, with literally life-and-death stakes. I really don't see any way around that, unless the meds can be pre-distributed, but I've never seen any sign of willingness to do that. The authorities have always gone out of their way to discourage people from acquiring medications prospectively. Of course, that may change when a showdown with Saddam is in the offing. Perhaps there is some kind of intermediate solution. For example, if we have enough stocks on hand, they could be distributed to every corner drug store, so that everybody could have some reasonable assurance of getting treatment promptly. They'd have to self-treat, but again, as this comes closer to a climax, the necessary education steps could be taken to make that feasible, at least if the vaccine can be administered orally. That approach would also be fool-proof against any terrorist attempt to disrupt distribution (e.g. 2AM - drop anthrax on subway tracks, 10 AM - suicide attack on treatment center).