A study of two new vaccines that could counter a bioterrorism threat is underway at Saint Louis University School of Medicine. Researchers are testing two experimental smallpox vaccines to possibly replace the existing vaccine, which is known as Dryvax. Saint Louis University’s Doctor Sharon Frey, the principal investigator for the study, says a replacement for Dryvax could be beneficial. Dryvax has side effects. They include fevers,headaches, and other ailments associated with viral infection. Side effects aside, Doctor Frey says it makes sense to be prepared for a possible bioterrorism threat. Researchers are looking for 90 adult volunteers of various racial and ethnic backgrounds.