A smallpox outbreak has always been my greatest concern. That is the scenario I have been trying to plan for. I recently contacted Dr. D. A. Henderson (one of the original people who eliminated smallpox and currently is head of bioterrorism defence at John Hopkins (this is not his correct title - I will try and find it and post it later). I asked him if it was possible to use arm to arm transfer of vaccine if the supply of vaccine ran out. Here is his reply.
"The scheme you propose could be done. In fact, this was the technique employed for propogating vaccine throughout most of the 19th century. The problem is that such as Hepatitis B and C, as well as HIV, can be transferred in this manner and so, unless one's back is really against the wall, this is not a technique to be advocated. D.A.Henderson "
I would like to know more - for example how much do you use, how do you actually do it, can it be collected and mixed with say saline to dilute it to make it go farther, how do you lessen the risk of bacterial contamination, can it be dried and stored etc. Many questions and very hard to find answers.