Observer-blind, partially randomized, multi-center dose-escalation Phase I study in healthy adults below 40 years of age.
180 subjects will be enrolled in 6 treatment groups (different doses; different formulation: with/without adjuvant); vaccinations will be given I.M.(intramuscular) into the deltoid region on Days 0, 28 and 56. Study participants will be followed up until one year after first vaccination.
Subjects in the 48µg and 90µg Treatment groups who received a complete Primary immunization schedule will be included into a Booster Extension 13 months after the first immunization.