500 Subjects (thereof, 250 aged 50 - 64 years and 250 aged 65 years and older) will be randomized in a (3:3:3:1) ratio to receive either VLA84 75 µg w/o (without) Alum, VLA84 200 µg w/o Alum, VLA84 200 µg w/ (with) Alum (150 subjects each), or placebo (50 subjects), as i.m. (intramuscular) vaccinations into alternating arms, on Days 0, 7 and 28