A Study of a Vaccine Against Respiratory Syncytial Virus (RSV) When Given Alone and Together With a Vaccine Against Diphtheria, Pertussis and Tetanus (Tdap) Viruses Followed by a 2nd Dose of the RSV Vaccine to Healthy Non-Pregnant Women

Inclusion Criteria: Primary study * Subjects who, in the opinion of the investigator, can and will comply with the requirements of the protocol. * Written or witnessed/thumb printed informed consent obtained from the subject prior to performance of any study specific procedure. * Healthy female subjects; as established by medical history and clinical examination, aged 18 to 45 years at the time of the 1st vaccination; * Female subjects of childbearing potential may be enrolled in the study, if the subject: * has practiced adequate contraception for 30 days prior to primary vaccination, and * has a negative pregnancy test on the day of primary vaccination, and * has agreed to continue adequate contraception for 90 days after completion of the vaccination. * No local condition precluding injection in both left and right deltoid muscles. Extension study * Completed primary study and received 1st dose of a study vaccine. * Written or witnessed/thumb printed informed consent obtained from the subject prior to performance of any study specific procedure to the study extension. All subjects must satisfy ALL the following criteria: * Subjects who can and will comply with the requirements of the protocol. * Female subjects remain healthy; as established by medical history and clinical examination, aged 18 to 45 years at the time of the 1st vaccination; * Female subjects of childbearing potential are eligible for the extension, if the subject: * has practiced adequate c…