According to this article, the US currently has enough vaccine for about 15.4 million vaccinations. They're testing an idea to dilute the vaccine 5:1 to stretch it in an emergency.

Question, does anyone know if a smallpox vaccination is good for a lifetime or if it has to be "boosted" from time to time like a lot of other vaccinations? The US stopped giving smallpox vaccinations in 1972. Those of us who were born before then were vaccinated. However, tens of millions of people born since weren't.

If it turns out that people would need a smallpox booster shot, I wonder if the diluted version would be adequate for that purpose. Personally, I'd rather see the vaccine given to the younger people and take my chances. After all, what would our future be like if millions of the younger generation were lost in an attack (no snide remarks, please!)? Smallpox is much more dangerous than anthrax.