Phase I/II Trial of Modified Vaccinia Virus Ankara (MVA) Vaccine This study is currently recruiting patients. Sponsored by National Institute of Allergy and Infectious Diseases (NIAID) Purpose This study will test the safety of an experimental vaccine called modified vaccinia virus ankara (MVA) and determine if it confers protection against the smallpox virus (variola). There is an existing vaccine, called Dryvax® (Registered Trademark), which is effective against smallpox; however, this vaccine can cause various side effects, including some that, on rare occasions, can be life-threatening. Dryvax® (Registered Trademark) has not been used in the United States since childhood vaccination was...