A Study to Assess Safety, Tolerability and Immunogenicity of RSVpreF From Multidose Vials in Healthy Female Adults.

Respiratory Syncytial Virus (RSV) is a common type of virus (germ) that can cause severe illness, where medical help is needed. RSV can lead to airway diseases in all ages. Vaccines help your body make antibodies. These antibodies help fight against diseases. This is called an immune response.

The purpose of this study is to learn about the safety, tolerability, and immunogenicity of a RSV vaccine called RSVpreF. RSVpreF comes either as:

* a single dose in a container (called a vial),
* or in a vial that holds multiple doses. A multidose vial contains more than one dose of RSVpreF.

  2-Phenoxyethanol (2-PE) is a preservative to help prevent the growth of bacteria (germs). This study will compare RSVpreF with an added preservative called 2-phenoxyethanol (2-PE) from a multidose vial, to RSVpreF without an added preservative, from a single-dose vial.

This study is looking to enroll nonpregnant, nonbreastfeeding, healthy female participants.

Participants will need to visit the study clinic two times during the study. Participants will also have a final safety telephone call at the end of the study. All participants will receive a single shot of the study vaccine either from:

* a multidose vial (with the preservative), or
* from a single-dose vial (without the preservative) at the first study clinic visit.

Blood samples will be taken at the two study clinic visits. Each participant will take part in the study for around 6 weeks.


Eligibility Criteria:
Inclusion Criteria:

1. Healthy nonpregnant, nonbreastfeeding females 18 through 49 years of age at Visit 1 (Day 1).
2. Willing and able to comply with all scheduled visits, investigational plan, lifestyle considerations, and other study procedures.
3. Available for the duration of the study and can be contacted by telephone during study participation.
4. Capable of giving signed informed consent as described in the protocol which includes compliance with the requirements and restrictions listed in the ICD and in the protocol.

Exclusion Criteria:

1. Any medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
2. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the vaccines being administered in the study.
3. Immunocompromised participants with known or suspected immunodeficiency, as determined by history, laboratory tests, and/or physical examination.
4. History or active autoimmune disease, including but not limited to systemic or cutaneous lupus erythematosus, autoimmune arthritis/rheumatoid arthritis, Guillain-Barré syndrome, multiple sclerosis, Sjögren's syndrome, idiopathic thrombocytopenia purpura, glomerulonephritis, autoimmune thyroiditis, giant cell arteritis (temporal arteritis), psoriasis, and insulin-dependent diabetes mellitus (type 1).
5. Bleeding diathesis or any condition that would, in the opinion of the investigator, contraindicate intramuscular injection.
6. Previous vaccination with any licensed or investigational RSV vaccine, or planned receipt of a nonstudy RSV vaccine throughout the study.
7. Receipt of chronic systemic treatment with immunosuppressant medications (including cytotoxic agents or systemic corticosteroids), or radiotherapy, within 60 days before enrollment through conclusion of the study.
8. Receipt of blood/plasma products or immunoglobulin within 60 days before study intervention administration or planned receipt throughout the study.
9. Current alcohol abuse or illicit drug use.
10. Individuals who are pregnant or breastfeeding.
11. Participation in other studies involving an investigational product within 28 days prior to study entry and/or during study participation. Participation in purely observational studies is acceptable.
12. Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.