A Study to Evaluate the Safety and Immunogenicity for Regimen Selection of Ad26.RSV.preF and/or RSV preF Protein Combinations Followed by Expanded Safety Evaluation in Adults Aged 60 Years and Older

Inclusion Criteria:

- Before randomization, a woman must be postmenopausal (postmenopausal state is defined
as no menses for 12 months without an alternative medical cause) and not intending to
conceive by any methods

- In the investigator's clinical judgment, participant must be either in good or stable
health. Participants may have underlying illnesses such as hypertension, type 2
diabetes mellitus, hyperlipoproteinemia, or hypothyroidism, as long as their symptoms
and signs are medically controlled. If they are on medication for a condition, the
medication dose must have been stable for at least 12 weeks preceding vaccination and
expected to remain stable for the duration of the study. Participants will be included
on the basis of physical examination, medical history, vital signs, and 12-lead
electrocardiogram (ECG) performed at screening

- For participants in Cohorts 1 and 2 only: Participant must be healthy on the basis of
clinical laboratory tests performed at screening. If the results of the laboratory
screening tests are outside the central laboratory normal reference ranges and
additionally within the limits of toxicity Grade 2 according to the United States (US)
Food and Drug Administration (FDA) toxicity, the participant may be included only if
the investigator judges the abnormalities or deviations from normal to be not
clinically significant and appropriate and reasonable for the population under study.
This determination must be recorded in the participant's source documents and
initialed by the investigator

- From the time of each vaccination through 3 months after each vaccination, participant
agrees not to donate blood

- Participant must be willing to provide verifiable identification, have means to be
contacted and to contact the investigator during the study

Exclusion Criteria:

- Per serology testing in Cohorts 1 and 2 and per medical history in Cohort 3:
Participant has chronic active hepatitis B or hepatitis C infection, documented by
hepatitis B surface antigen and hepatitis C antibody, respectively

- Per serology testing in Cohorts 1 and 2 and per medical history in Cohort 3:
Participant has human immunodeficiency virus (HIV) type 1 or type 2 infection

- Participant has had major psychiatric illness and/or drug or alcohol abuse which in
the investigator's opinion would compromise the participant's safety and/or compliance
with the study procedures

- Participant has a known allergy, or history of anaphylaxis or other serious adverse
reactions to vaccines or vaccine components (including any of the constituents of the
study vaccine)

- Participant has received respiratory syncytial virus (RSV) vaccine in a previous RSV
vaccine study at any time prior to randomization.