New smallpox vaccines for an ancient scourge.

The potential use of variola virus, a Class A agent of bioterrorism, remains a concern. In an effort to prepare for a possible smallpox outbreak due to an intentional release of variola, the U.S. government and industry have been evaluating vaccines stored in the National Strategic Stockpile including cell culture grown ACAM2000 and modified vaccinia Ankara, IMVAMUNE, in clinical studies. This paper discusses smallpox vaccines studies conducted at the Saint Louis University Center for Vaccine Development.