Researchers at the University of California, Irvine have identified an alternative to the existing smallpox vaccine, which can hopefully replace the current biodefense stockpile that seems to have amassed.
The vaccine in question was developed from a modified vaccinia virus Ankara (MVA). MVA produces the same antiviral response in humans and animal studies as the current smallpox vaccine named Dryvax. Dryvax has caused serious complication in some people, and MVA has been administered with little or no adverse side effects.
Read more at http://www.sciencedaily.com/releases/2008/01/080107090951.htm, particularly regarding the use of microarray chips to determine how serum antibodies responded to the vaccinia proteins.