This study is a Phase 2 randomized, open-label, non-placebo controlled, multi-site clinical trial that will evaluate two intradermal (ID) regimens for Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) vaccine compared to the standard subcutaneous (SC) regimen in healthy, vaccinia-naïve adults 18 to 50 years of age, inclusive. At least 210 participants will be enrolled and randomized to one of three study arms. The two dose sparing strategies include one-fifth (2 x 10^7) and one-tenth (1 x 10^7) of the standard dose of MVA-BN administered ID on Day 1 and 29 (Arm 1 and 2, respectively). The comparator arm (Arm 3) will be the 2-dose standard (1 x 10^8) MVA-BN SC regimen.
The study will enroll a 1:1:1 randomization allocation. Participants will not be stratified by clinical trial site, demographic characteristics or human immunodeficiency virus (HIV) infection status; however, these data will be collected during screening and enrollment. Each participant may be screened either in a separate visit in the 7 days prior to Day 1 or on Day 1.
The primary hypothesis involves a two-step hierarchical process. The study will first test non-inferiority of the 2 x 10^7 ID regimen relative to 1 x 10^8 SC (standard dose regimen). If the 2 x 10^7 ID regimen is non-inferior to the standard dose regimen, hypothesis testing will proceed to test non-inferiority of the 1 x 10^7 ID regimen relative to the standard dose regimen.
The primary objectives are: 1) to determine if peak humoral immune responses following an ID regimen of 2 x 10^7 50% Tissue Culture Infectious Dose (TCID50) MVA-BN are non-inferior to the licensed regimen of 1 x 10^8 MVA-BN administered SC; 2) to determine if peak humoral immune responses following an ID regimen of 1 x 10^7 TCID50 MVA-BN are non-inferior to the licensed regimen of 1 x 10^8 MVA-BN administered SC.
Criteria:Be 18 - 50 years of age; Able to read the written informed consent, states willingness to comply with all study procedures, and is anticipated to be available for all study visits.; In good general health as evidenced by medical history, physical examination, and clinical judgement of the investigator to be in stable state of health.; *Participants with pre-existing stable chronic medical conditions defined as conditions not requiring significant change in therapy or hospitalization for worsening disease in the 4 weeks prior to enrollment can be included at the discretion of the investigator. This includes stable, well-controlled HIV positive individuals.; If HIV infected individual, they must be on suppressive Antiretroviral therapy (ART) for at least 6 months, report a cluster of differentiation 4 (CD4) count of greater than 350 cells/uL and no Acquired Immune Deficiency Syndrome (AIDS)-defining illness in the last year.