This is a randomized, observer-blind, placebo-controlled, multicenter Phase 2 study.

In the Run-in phase, a total of 120 subjects aged 18 to 40 years will be randomized 1:1:1:1 to receive one of three VLA15 doses (VLA15 low dose, VLA15 medium dose, VLA15 high dose) or Placebo (30 subjects per treatment group) as intramuscular vaccinations on Days 1, 29 and 57. Dosing will be adjusted by injection volume.

In the Main Study phase, a total of 450 subjects aged 18 to 65 years will be randomized 2:2:1 to receive one of two VLA15 doses that are selected from the Run-in Phase for further investigation (180 subjects each) or placebo (90 subjects), as intramuscular vaccinations on Days 1, 29 and 57. Subjects will be enrolled in two age groups (18-49 years and 50-65 years) in a ratio of approx. 2:1.

In both study phases, the target is to enroll approx. 10 % or more of subjects that are baseline seropositive for Borrelia burgdorferi sensu latu (Bb s.l.).

This clinical trial is completed with results.  The full results can be found here.