A multi-center, open-label, escalating dose-ranging study to assess the safety, reactogenicity, and immunogenicity of four different VAX125 vaccine doses; 0.5 µg, 1.0 µg, 2.0 µg, or 3.0 µg, delivered i.m. as a single dose vaccination on Day 0. Hypothesis: VAX125 is safe and immunogenic at one or more of the doses tested.

A total of 80 community-living adults who are ≥65 years of age will be enrolled across the four dose groups. Following vaccination, each subject will remain at the study site for at least 30 minutes to be observed for any immediate reactogenicity complaints associated with the Day 0 vaccination. Subjects will also be evaluated during clinic visits on Study Days 1, 7, 14, and 28 following vaccination. In addition, a safety follow-up telephone contact will occur on post vaccination Day 3.

There will be 20 subjects per dose group. Up to 3 study sites will enroll 6-10 subjects per dose group over a two-day enrollment period. Progression to the next higher dose group will take place only if the Safety Monitoring Committee (SMC) assessment of the 30 (+15) minutes, Day 0, and Day 1 post vaccination safety data; Day 3 telephone report: and the Day 0 and Day 1 serum C-reactive protein (CRP) results concludes that the lower dose was well tolerated.

Inclusion Criteria:

• Adult men or women aged 65 or older; female subjects must be post menopausal.
• Live in the community, independently or in an assisted living environment
• Based on the results of the Short Portable Mental Status Questionnaire (SPMSQ), be rated as normal or have no greater than mild severity dementia.
• As defined by the Canadian Study of Health and Aging Clinical Frailty Scale (CSHA-CFS), fitness ranging from very fit to mildly frail; Classes 1 to 5 of 7.
• Healthy volunteers, as determined by medical history, physical examination (PE), vital signs, and clinical safety laboratory examinations.
• Able to comprehend the study requirements, agree to its provisions, have the ability to adhere to the provisions of the study, and give written informed consent prior to study entry.
• Willing to receive the unlicensed (VAX125) vaccine given as an i.m. injection.
• Willing to provide multiple blood specimens collected by venipuncture.

Exclusion Criteria:

• Persons who in the opinion of the Investigator, have a psychiatric illness, a chronic illness (e.g., diabetes or liver or kidney disease), or who are taking a concomitant therapy or have any other condition that would interfere with the subject's participation in the study or interpretation of the study results.
• Persons having cancer or have received treatment for cancer within three years (persons with a history of cancer who are disease-free without treatment for three years or more are eligible.
• Persons with impaired immune responsiveness (of any cause), including diabetes mellitus.
• Persons presently receiving or having a recent history of receiving (within the past six months) any medication or therapeutic modality that affects the immune system such as allergy shots, immune globulin, interferon, immunomodulators, radiation therapy, cytotoxic drugs or drugs known to be frequently associated with significant major organ toxicity, or systemic corticosteroids (oral or injectable). Inhaled and topical corticosteroids are allowed.
• Persons who have had a prior serious reaction to influenza vaccine.
• Persons with a history of anaphylactic-type reaction to injected vaccines.
• Persons with a history of drug or chemical abuse in the year prior to screening.
• Persons currently participating in another research study involving study medications (drugs or vaccines) or who have participated within 30 days of vaccination.
• Persons who have received blood or blood products within eight weeks prior to vaccination or are planning to receive blood or blood products during the study period.
• Persons who have donated blood or blood products within eight weeks prior to vaccination or plan to donate at any time during the study.
• Persons with acute disease within 72 hours prior to vaccination defined as the presence of a moderate or severe illness as determined by the Investigator through medical history and physical examination. Vaccination can be delayed until the subject has recovered.
• Persons with significant cardiovascular disease e.g., New York Heart Associate (NYHA) Class 3 or 4 congestive heart failure; myocardial infarction within the past six months; unstable angina, coronary angioplasty within the past six months; uncontrolled ventricular cardiac arrhythmias; resting heart rate (HR) >100 beats per minute (bpm)
• Persons with a history of chronic obstructive pulmonary disease or history of other lung disease.

Serious adverse events were collected for 1 year following vaccination. All adverse events were collected for 28 days following vaccination.