Smallpox can't be triggered by the vaccine, since it's cowpox. Much of any potential hysteria can be pre-empted with that information.
IF Iraq has powdered small pox then perhaps they would trigger release of that viral agent upon the institution of a mass vacination program. Clearly there would be many who would blame the vacine for the outbreak and the resultant chaos would be worse.
As to the effect of the old cacinations - they have some marginal effectiveness but are one is probably not completely immune. The more booster shots one has had for smallpox the more likely one is to be immune. Sometimes with second and third vacinations the oozing sore and the scar are almost negligable. The cowpox vacination method is 18th Century technology and George Washington agreed to be vacinated with this vacine as a means of encouraging others to get their shots. Yes, he was immune due to an earlier case of smallpox he had sufffered while traveling in the West Indies.
Most interesting is the analysis of the inertial that is so rampant throughout the establishments in DC. So many of these functionaries still do not understand the rules should have changed as of 9/11. If Al Qaeda is intentionally waiting for a follow on major attack then it is a brilliant strategy. They are presuming the natural disputatiosness of American politics will paralyze the USA in retatialtory action within a short time and given the Democrats behavior recently they may well be correct.
Stay well - Stay safe - Stay armed - Yorktown
Smallpox can't be triggered by the vaccine, since it's cowpox. Much of any potential hysteria can be pre-empted with that information.
I don't think they're so well organized. But they could be with Iraqi help.