Most people today have no immunity to smallpox. The vaccine begins to wear off in many people after ten years. Mass vaccination for smallpox came to a worldwide halt around twenty-five years ago. There is now very little smallpox vaccine on hand in the United States or anywhere else in the world. The World Health Organization once had ten million doses of the vaccine in storage in Geneva, Switzerland, but in 1990 an advisory committee recommended that most of it be destroyed, feeling that smallpox was longer a threat. Nine and a half million doses are assumed to have been cooked in an oven, leaving the W.H.O. with a total supply of half a million doses — one dose of smallpox vaccine for every twelve thousand people on earth. A recent survey by the W.H.O. revealed that there is only one factory in the world that has recently made even a small quantity of the vaccine, and there may be no factory capable of making sizable amounts.