- Cohort 1: A first cohort of one hundred nineteen subjects (119) will be randomized; of these, seventy five (75) will be dosed with the lowest dose of the quadrivalent VLP vaccine, nineteen (19) will be dosed with the medium dose of the quadrivalent VLP vaccine, and twenty five (25) will receive a placebo. The 7-day safety data after the immunization will be collected and reviewed by the Data and Safety Monitoring Board (DSMB) consisting of the Principal Investigator (PI), the Sponsor's Medical Officer and three external medical experts as voting members, prior to permitting immunization with the cohort 2.