A study to rank different dosages of antigen of GlaxoSmithKline (GSK) Biologicals’ investigational Respiratory Syncytial Virus (RSV) vaccine (GSK3003891A), based on their immune response and safety, when administered to healthy adult women

Subjects who, in the opinion of the investigator, can and will comply with the requirements of the protocol.

• Written informed consent obtained from the subject prior to performance of any study specific procedure.
• Non-pregnant female between, and including, 18 and 45 years of age at the time of study vaccination.
• Healthy subjects as established by medical history and clinical examination before entering into the study.
• Female subjects of non-childbearing potential may be enrolled in the study

Non-childbearing potential is defined as pre-menarche, hysterectomy, ovariectomy or post-menopause.

• Female subjects of childbearing potential may be enrolled in the study, if the subject:

Use of any investigational or non-registered product other than the study vaccines within 30 days prior to study vaccination, or planned use during the study period.

• Concurrently participating in the active phase of another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational vaccine/product.
• Chronic administration of immunosuppressants or other immune-modifying drugs, as well as administration of long-acting immune-modifying drugs, within 6 months prior to study vaccination, or planned administration until 90 days post-vaccination. For corticosteroids, this will mean prednisone ≥ 10 mg/day, or equivalent. Inhaled and topical steroids are allowed.
• Administration of immunoglobulins and/or any blood products during the period starting 3 months before the study vaccination, or planned administration until 90 days post-vaccination.
• Planned administration/administration of a vaccine not foreseen by the study protocol within the period starting 30 days before and ending 30 days after study vaccination, with the exception of any licensed influenza vaccine which may be administered ≥ 15 days before or after study vaccination.
• Previous experimental vaccination against RSV.
• History of any neurological disorders or seizures.
• Family history of congenital or hereditary immunodeficiency.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination
• History of or current autoimmune disease
• Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality as determined by physical examination and/or Medical History.
• Lymphoproliferative disorder or malignancy within previous 5 years.
• History of any reaction or hypersensitivity likely to be exacerbated by any component of the study vaccine.
• Hypersensitivity to latex.
• Any medical condition that in the judgment of the investigator would make intramuscular injection unsafe.
• Current alcohol and/or drug abuse.
• Acute disease and/or fever at the time of enrolment.

For subjects with acute disease and/or fever at the time of enrolment, Visit 1/Day 0 will be rescheduled within the allowed recruitment period.

• Body mass index (BMI) > 40 kg/m².
• Pregnant or lactating female.
• Planned move to a location that will prohibit participating in the trial until study conclusion.
• Any other condition that the investigator judges may interfere with study procedures or findings.