Up to 220 eligible subjects will be enrolled into one of five treatment groups. It is anticipated that some of the randomized study subjects may not complete the study; subjects who withdraw or are discontinued, will not be replaced. Randomization will be stratified by age (60 to <75 years and ≥ 75 years) in order to distribute the proportion of such persons in each age group equally across treatment groups.

Treatments will comprise a single IM dose of a placebo or RSV-F protein nanoparticle vaccine on Day 0, with concurrent IM immunization with a licensed inactivated influenza vaccine. A rescue dose of the licensed TIV will be provided to subjects in all groups except the placebo group on Day 28, the placebo group will receive saline. For each subject, study follow-up will span approximately one year from the first immunization (on Day 0) for all subjects.

Inclusion Criteria:

• Adult males and females, ≥ 60 years of age, without symptomatic cardiopulmonary disease. Note that subjects who have any functional limitation or symptoms related to cardiac and/or pulmonary disease (including asthma or other episodic symptoms), or who receive ongoing therapy to control symptoms or functional limitation, are not eligible. The following are examples of subjects who may bear cardio-pulmonary diagnoses but who would remain eligible:

  1. Subjects on stable (no change in ≥ 2 months) therapy for findings (e.g., hypertension or hyperlipidemia) that are not associated with current symptoms or disability.
  2. Subjects who receive intermittent prophylaxis for risks associated with asymptomatic findings (e.g., antibiotic prophylaxis prior to dental procedures in a subject with asymptomatic mitral valve prolapse).
  3. Other clinically insignificant findings, not deemed to be associated with increased risk due to respiratory viral infections as determined by the Investigator.

• Free of other illnesses which are believed to increase the risk of influenza or influenza related complications including: diabetes mellitus, congenital or acquired blood dyscrasias, renal or hepatic dysfunction, and morbid obesity.

• Willing and able to give informed consent prior to study enrollment.

• Able to comply with study requirements.

Exclusion Criteria:

• Participation in research involving investigational product (drug / biologic / device) within 45 days before planned date of first vaccination and/or planned participation at any time during the study.
• History of a serious reaction to any prior vaccination or known allergy to constituents of licensed TIV (e.g., egg proteins).
• History of Guillain-Barré Syndrome within 6 weeks following a previous influenza vaccine.
• Receipt of any influenza vaccine within the preceding 3 months.
• Receipt of any vaccine in the 4 weeks preceding the study vaccination and planned receipt of a licensed vaccine any time prior to Day 56.
• Receipt of an RSV vaccine at any time.
• Any known or suspected immunosuppressive condition, acquired or congenital, as determined by medical history and/or physical examination.
• Chronic administration (defined as more than 14 continuous days) of immunosuppressants or other immune-modifying drugs within 6 months prior to the administration of the study vaccine. An immunosuppressant dose of glucocorticoid will be defined as a systemic dose ≥10 mg of prednisone per day or equivalent. The use of topical, inhaled, and nasal glucocorticoids will be permitted provided these are not administered for diagnoses inconsistent with the inclusion criteria. The use of inhaled glucocorticoids, although typically not associated with system absorption, will generally indicate the presence of a diagnosis inconsistent with inclusion criteria 1 or 2.
• Administration of immunoglobulins and/or any blood products within the 3 months preceding the administration of the study vaccine or during the study.
• Acute disease at the time of enrollment (defined as the presence of a moderate or severe illness with or without fever, or an oral temperature >38.0°C on the planned day of vaccine administration).
• Known disturbance of coagulation.
• Suspicion or recent history (within one year of planned vaccination) of alcohol or other substance abuse.
• Any condition that in the opinion of the Investigator would pose a health risk to the subject if enrolled or could interfere with evaluation of the vaccine or interpretation of study results (including neurologic or psychiatric conditions deemed likely to impair the quality of safety reporting).