6. Was ever vaccinated with a licensed or investigational smallpox vaccine with the exception of subjects in Group 6. Includes Dryvax, Acam2000, LC 16 m8, MVA-based vaccine candidate or licensed vaccines, and Imvamune or Imvanex. EXCEPTION: Group 6 should have had two 1 x 10^8 TCID 50 doses of MVA-BN 19 - 45 days apart SC or IM as part of participation in DMID vaccine trials 11-0021 or 09-0002. First dose must have been administered no earlier than 2010.