21.   Federal officials say they have begun an urgent search for more supplies of the medicine used to treat people who have dangerous reactions to the smallpox vaccine.

22.   For instance, troubles with quality control are such that no stored smallpox vaccine in the United States can now be used except in emergencies, Federal officials say.

23.   He also argues that a forthcoming anthrax vaccine, like the smallpox vaccine, should be stockpiled for the general population, rather than just for the military.

24.   He took part in the clinical trial of an experimental smallpox vaccine derived from chick embryos.

25.   Henderson and other speakers at the meeting cited myriad problems if smallpox vaccine were to be offered to all Americans who want it.

26.   Henderson has called for a crash program to develop sufficient smallpox vaccine to immunize Americans in case of a terrorist-initiated outbreak.

27.   However, the smallpox vaccine has essentially eliminated the presence of the disease in most of the world.

28.   However, because none of the smallpox vaccine is licensed, its use would require signed consent from each recipient.

29.   If their models are correct, the researchers add, current government contracts for new smallpox vaccine should eventually provide enough protection.

30.   In addition, foreign governments have called, he said, inquiring whether they could also buy the smallpox vaccine.