A Study to Assess the Safety, Reactogenicity and Immunogenicity of GlaxoSmithKline (GSK) Biologicals' RSV Investigational Vaccine (ChAd155-RSV) (GSK3389245A) in Healthy Adults

Inclusion Criteria

• 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 performing any study specific procedure
• A male or female between, and including, 18 and 45 years of age at the time of first 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
• Female subjects of childbearing potential may be enrolled in the study, if the subject:
• has practiced adequate contraception for 30 days prior to vaccination, and
• has a negative pregnancy test on the day of vaccina-tion, and
• has agreed to continue adequate contraception during the entire treatment period and for 2 months after completion of the vaccination series

Exclusion Criteria

• Concurrently participating in 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
• Use of any investigational or non-registered product other than the study vaccines during the period starting 30 days before the first dose of study vaccines, or planned use during the study period
• Chronic administration of immunosuppressants or other immune-modifying drugs within 6 months prior to study vaccination, or planned administration during the study period
• Planned administration/administration of a vaccine not foreseen by the study protocol in the period starting 30 days before the first dose and ending 30 days after the last dose of vaccine administration, with the exception of any licensed influenza vaccine which may be administered ≥ 15 days before the first dose and ≥ 15 days after the last dose of study vaccine
• Administration of immunoglobulins and/or any blood products during the period starting 3 months before the first dose of study vaccines or planned administration during the study period
• Blood donation within 4 months prior to study entry or planned blood donation at any time during the study
• Previous vaccination against RSV
• Previous vaccination with a recombinant simian or human adenoviral vaccine
• Previous Bexsero or other vaccination against Neisseria meningitidis serogroup B
• History of or current autoimmune disease
• Family history of congenital or hereditary immunodefi-ciency
• History of any reaction or hypersensitivity likely to be exacerbated by any component of the study vaccines.
• History of any neurological disorders or seizures
• History of transient thrombocytopenia or neurological complications following any prior vaccination
• Hypersensitivity to latex
• Hypersensitivity to Bexsero's active substances or to any of its excipients
• Allergic reaction to kanamycin
• Any medical condition that in the judgment of the investi-gator would make intramuscular injection unsafe
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination
• Acute disease and/or fever at the time of enrolment
• Acute or chronic, clinically significant pulmonary, cardio-vascular, hepatic or renal functional abnormality, as de-termined by physical examination or laboratory screening tests
• Malignancy within previous 5 years or lymphoproliferative disorders
• Any clinically significant or any ≥ Grade 2 haematological laboratory abnormality
• Body mass index > 40 kg/m2
• Current alcohol and/or drug abuse
• Pregnant or lactating female
• Any other condition that the investigator judges may interfere with study procedures or findings
• Planned move to a location that will prohibit participating in the trial until study end