Inclusion Criteria:

• Able to speak and read English
• Male or Female, 65 years and older by date of enrollment
• Weight of 110 lbs or greater
• Has received influenza vaccine in the past seasons without severe adverse reactions
• Willing to receive an FDA-approved age-appropriate and CDC-recommended influenza vaccine for each of the 2022-23, 2023-24, and 2024-25 influenza seasons
• Willing to withhold all other vaccinations 2 weeks prior and 2 weeks after flu vaccination for the 2022-23, 2023-24, and 2024-25 influenza seasons
• Willing and available to participate in 19 study visits over three years around influenza vaccination
• Willing to provide blood samples at sixteen visits over three years
• Willing to agree to genomic testing of samples and sharing of de-identified genomic data generated from samples at the conclusion of the research

Exclusion Criteria:

• Received any vaccine (shingles, pneumococcal, COVID, etc.) within 2 weeks of anticipated flu vaccination for the 2022-23, 2023-24, and 2024-25 influenza seasons.

• Has already received an influenza vaccine for the approaching influenza season (2022-23)

• Has known allergy to eggs or any component of the flu vaccine. [Although the Advisory Committee on Immunization Practices (ACIP) has concluded that a history of anaphylactic/anaphylactoid or severe allergic reaction to eggs should no longer be considered a contraindication to vaccination with any age-appropriate vaccine, for the purposes of this research study we elected to exclude individuals with these allergies]

• History of Guillain-Barre syndrome (GBS)

• Body temperature greater than 100.3°F (38°C) on date of vaccination or within 2 days prior to vaccination by participant report (study entry may be delayed to meet this requirement)

• Rockwood Frailty Index score of >0.21

• Known history of any of the following co-morbid conditions:

  • Chronic or recent (within past 2 months) infection requiring oral or intravenous antibiotics, antifungals, or antivirals
  • Cancer other than basal cell carcinoma requiring active surgical or medical treatment (chemotherapy or radiation therapy)
  • Congestive Heart Failure
  • Ischemic Heart Disease
  • Congenital abnormalities (PI to evaluate)
  • Paget's disease
  • Renal failure requiring ongoing dialysis
  • Chronic obstructive pulmonary disease, emphysema, or asthma
  • Severe autoimmune disease requiring biological therapy
  • Diabetes mellitus requiring insulin
  • Use of medicines during past 6 months known to alter immune response such as high-dose corticosteroids (≥ 10 mg/day of prednisone or equivalent)
  • HIV, AIDS or other immunodeficiency disorders
  • Recent (≤ 3 months) severe trauma or major surgery (PI to evaluate)
  • Current substance and/or alcohol abuse

• Patients currently residing in the Department of Correction

• Inability to comply with the protocol requirements

• Any other condition that, in the opinion of the PI, might interfere with study objectives