Prevention of GBS Colonization Via Immunity

Inclusion Criteria: * Participated in and completed the group B Streptococcus (GBS) Screening Protocol * Non-pregnant women * Aged 18-40 years at time of the screening protocol * Currently sexually active at time of enrollment (sex with a male at least once in the last 4 months) * Current use of effective birth control methods and stated intention to use the method for at least the next 30 days * Provision of written informed consent * Intention to stay in the geographical area for the next 18 months * Access to telephone Exclusion Criteria: * Group B Streptococcus (GBS) positive by culture (vaginal and/or rectal), or culture positive for streptococcal strains that cross-react with GBS typing sera (vaginal and/or rectal). * Pregnancy (all women will receive a urine pregnancy prior to vaccination). * Any condition which in the opinion of the investigator would pose a health risk to the subject or interfere with the evaluation of the vaccine. * Serious underlying disease, which is known at the time of vaccination (including: immunodeficiency, active or chronic hepatitis, immunosuppressive conditions which require systemic steroid therapy, or treatment for a malignancy during the past year). * Receipt of any vaccine, blood product, or experimental medicine within the past 30 days with the exception of a licensed inactivated influenza vaccine. * Plans to receive any vaccine, blood product, or experimental medicine in the next 30 days with the exception of a licensed inactivate…