Thanks for the thoughtfulness of your response. The scenario you have described is the worst case scenario. I'm sure that the intelligence authorities have to be working to identify such plans. If the terrorist organizations are willing to create a plan like 9-11, and since there are operatives still out in the field; the shipping of the weapons becomes the issue.
Currently, the anthrax attack in Sept 01 has escaped identification. It appears to me that the perp had sufficient containment to limit spread in an apartment or business. Somewhere there has to be traces of the same germ from the packaging. If the traces do not exist, then the packaging occured elsewhere and (more importantly) the manufacturing of the weapons occured outside the United States.
This poses the possibility that we have already been subjected to a biological attack by a foreign nation. I submit this is a higher possibility than domestic terrorism. The only gov't with enough to pull off the scheme is Iraq. North Korea probably doesn't have anthrax molecular biologists available. But, middle eastern college students abound in our nation. If one was bought off and entered Iraq, then they may be the perp.
Regarding ring vaccination strategies and the epidemiology of the spread of smallpox, there is one issue that you have omitted from your scenario. There is the possibility with voluntary immunization of the populace of creating "herd immunity". When a herd of cattle are susceptible to a disease, then it spreads faster if all cattle are susceptible. However, once a certain percentage of people are immune, it is possible to contain the spread of the disease more easily. Because not every individual is susceptible, some of the contagion decreases in the total population.
I submit to my colleagues on this board (who are physicians and public health officers) that herd immunity is the issue in our national defense against bioterrorism. Certainly, polio is not a likely weapon of choice. Nearly every American is immune to the virus. However, it was our own decision to stop protecting our children and it was our own lack of foresight that has created the first new generation totally susceptible to smallpox in over 100 years!
God help the politician who is silent when we request formally for the stockpiles to be released.
The type of vaccines needed to maintain herd immunity are likey to be different than the types used to stop an outbreak. For example the live oral polio vaccine causes a the immune system to build immunity faster than the killed version. Unfortunately the live polio vaccine sometimes mutates back to the virulent form and causes polio. While the live vaccine is no longer used in this country due to the rare but devastating side effect, it is used in countries like Afghanistan where polio is still endemic. If the US were to develop safer inactivated smallpox vaccines, the live vaccine would still be useful in case of an outbreak, because it can be given up to four days after exposure to smallpox.
We need to have bettter forethought about how diseases are exterminated in the future. If we stop vaccinating against polio after polio is erradicated, in thirty years or so we would have same kind of vulnerabilty to polio attacks as we now have to smallpox. After polio is "erradicated," WHO wants to erradicate the measles. We certainly don't want to repeat the same mistakes with the measles that have been made with smallpox. All it takes is for someone to clandestinely freeze some samples of the virus.
The voluntary take up rate would have to be very high to give any useful "herd immunity". We have a problem in Britain at the moment with the take up of the MMR vaccine. The optimum vaccine take up rate is 97% or above, but in some areas it is below 80%. This has caused some isolated outbreaks of measles in these low take up areas. To prevent an uncontrollable Smallpox epidemic we would need over 80% of the population to be vaccinated. Its very unlikely that this could be done quickly by a voluntary vaccination campaign.
A key question is whether or not people who want voluntary vaccination will have to pay for the vaccine? Is there enough vaccine available to do volunary vaccinations and still vaccinate people in communities that are exposed after an attack? If there isn't enough vaccine and people have to use privately sourced vaccines for voluntary vaccination, then some impoverished groups will be left unprotected.
I often hear ignorant people in Britain say that children are the most at risk from a Smallpox attack. I don't know when routine Smallpox vaccination ended in the USA, but in Britain it ended in the 1960s. Therefore, people in their mid-30s are fully susceptible to it. Apparently, the Russians continued routine vaccination into the late 1970s. They weaponised Smallpox of course, so they had to make sure their population was immune.
Its funny the number of people who have told me that they are confident that they are safe even though they were vaccinated back in the 60s. I have a Russian colleague who was vaccinated in 1974 and she told me she wasn't worried about a Smallpox attack. I informed her that the Smallpox vaccine is only guaranteed to prevent infection for 5 years and 10 at the outside, although the disease suffered is usually less severe if Smallpox is contracted within 20 years. Oh well, whatever gives people hope!
If Al Qaeda has Smallpox, they are most likely to have the extremely deadly India-1967 strain of Smallpox, which the Soviets apparently gave to North Korea and goodness knows who else. Apparently, they manufactured 20 tons of it for use in their ICBMs and other weapons systems. Thus it certainly would be the most likely strain to have been stolen and sold to the highest bidder. This strain has caused Smallpox in people who were vaccinated more than 10 years before exposure, although the mortality rate is much lower than for non-vaccinees. The mortality rate with this strain is at least 50% for non-vaccinees and not the usual 30%, which is seen with most other strains.