This study is a Phase 2 randomized, open-label, non-placebo controlled, multi-site clinical trial that will evaluate two ID regimens for MVA-BN vaccine compared to the standard SC regimen in healthy, vaccinia-naïve adults 18 to 50 years of age, inclusive, (Stage 1). In Stage 2 of the study, the standard SC regimen will be evaluated in adolescents ages 12 through 17 years, inclusive, and compared to the standard SC regimen in adults ages 18 to 50, inclusive.~In Stage 1, approximately 230 adult 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. Stage 1 will enroll a 1:1:1 randomization allocation.~In Stage 2, approximately 210 healthy, vaccinia-naïve adults will be enrolled in a comparator arm (Arm 4) and will be given the standard, licensed regimen of 1x10^8 MVA-BN administered SC on Day 1 and 29 and will be combined with adults from Arm 3 (Stage 1) to be the comparator for the primary endpoint, non-inferiority testing. Approximately 210 healthy, vaccinia-naïve adolescents will be enrolled and given1x10^8 MVA-BN administered SC on Days 1 and 29 (Arm 5). The study will have a set target enrollment of at least 25% adolescents ages 12 to 14 years to ensure that adequate numbers of younger adolescents are enrolled.~The primary objectives are 1.) To determine if peak humoral immune responses in adults ages 18-50 years following an ID regimen of 2 x 10^7 TCID50 MVA-BN are non-inferior to the licensed regimen of 1 x 10^8 TCID50 MVA-BN administered SC; 2.) To determine if peak humoral immune responses in adults ages 18-50 years following an ID regimen of 1 x 10^7 TCID50 MVA-BN are non-inferior to the licensed regimen of 1 x 10^8 TCID50 MVA-BN administered SC. The Secondary Objectives are 1.) To determine if peak humoral immune responses in adolescents ages 12 to 17 years following administration of a 2-dose 1 x 10^8 TCID50 MVA-BN regimen administered SC are non-inferior to the response in adults ages 18 to 50 years who received the licensed 2-dose SC regimen of 1 x 10^8 TCID50 MVA-BN; 2.) To describe safety of a 2-dose 1 x 10^8 TCID50 MVA-BN regimen administered SC in adolescents ages 12 to 17 years
This study is a Phase 2 randomized, open-label, non-placebo controlled, multi-site clinical trial that will evaluate two ID regimens for MVA-BN vaccine compared to the standard SC regimen in healthy, vaccinia-naïve adults 18 to 50 years of age, inclusive, (Stage 1). In Stage 2 of the study, the standard SC regimen will be evaluated in adolescents ages 12 through 17 years, inclusive, and compared to the standard SC regimen in adults ages 18 to 50, inclusive.~In Stage 2, approximately 210 healthy, vaccinia-naïve adults will be enrolled in a comparator arm (Arm 4) and will be given the standard, licensed regimen of 1x10^8 MVA-BN administered SC on Day 1 and 29 and will be combined with adults from Arm 3 (Stage 1) to be the comparator for the primary endpoint, non-inferiority testing. Approximately 210 healthy, vaccinia-naïve adolescents will be enrolled and given 1x10^8 MVA-BN administered SC on Days 1 and 29 (Arm 5). The study will have a set target enrollment of at least 25% adolescents ages 12 to 14 years to ensure that adequate numbers of younger adolescents are enrolled.~The primary objectives are 1.) To determine if peak humoral immune responses in adults ages 18-50 years following an ID regimen of 2 x 10^7 TCID50 MVA-BN are non-inferior to the licensed regimen of 1 x 10^8 TCID50 MVA-BN administered SC; 2.) To determine if peak humoral immune responses in adults ages 18-50 years following an ID regimen of 1 x 10^7 TCID50 MVA-BN are non-inferior to the licensed regimen of 1 x 10^8 TCID50 MVA-BN administered SC.