This is a randomized, double-blind, placebo-controlled, phase II study to assess the safety and efficacy of the cytomegalovirus glycoprotein B (gB)/MF59 vaccine in preventing systemic cytomegalovirus infection (CMV) in healthy adolescent females. The study interventions include: intramuscular (IM) injection of the investigational vaccine, CMV gB)/microfluidized adjuvant 59 (MF59), delivered as 20 micrograms in 0.5 mL of vaccine or IM injection of 0.5 mL of saline placebo. Subjects will be randomized (1:1) to receive vaccine or saline placebo. The primary efficacy objective is to assess whether injection with 3 doses of the CMV gB/MF59 vaccine will reduce the acquisition of a systemic CMV infection in healthy CMV-seronegative adolescent females. This will be accomplished by comparing the rates of acquisition of systemic CMV infection, defined as detection of CMV in the urine or blood, between the placebo and CMV vaccine recipients beginning 1 month after the third dose of vaccine. The primary safety objective is to assess the local and systemic effects of immunization and adverse events (AE) with the CMV gB/MF59 vaccine when administered to female adolescents on a 0-, 1-, and 6-month schedule. This will be assessed by comparing the rates of specific local and systemic reactogenicity events and AEs between the vaccine and placebo groups. The endpoint for this trial will be a systemic infection, which will be defined as identification of CMV from the urine (chosen because it is the most common site for isolation of CMV) or blood (chosen because it is the most likely route by which CMV reaches the fetus). Approximately 2400 healthy females, age 12 to 17 years (at time of initial enrollment) will be recruited in order to obtain approximately 400 CMV-seronegative subjects for the vaccine trial. Collection of sera will occur at Screening, Study Day 0, Month 6, Month 7 and every 3 months after Month 7. Collection of urine will occur at Study Day 0, Month 1, Month 2, Month 6, Month 7 and every 3 months after Month 7. Safety/reactogenicity monitoring will consist of solicited signs and symptoms self-reported by memory aid on the day of vaccination and for 6 follow-up days. Unsolicited symptoms will be collected for the 30-day period (± 2 days) after each vaccination and followed to adequate resolution or stabilization. The study duration for each subject will be 31 months: 7 months on the study with 24 months of follow-up beginning 1 month after the last injection. There will be 14 scheduled visits. This study is linked to DMID protocol 06-0043.