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Understanding Flu Vaccine Response in Older Adults

This study aims to understand why older adults sometimes lose their ability to respond well to flu vaccines. Researchers will follow 75 adults, aged 65 and older, for three years. Each year, participants will receive a different FDA-approved flu vaccine: Fluzone® Quadrivalent High-Dose (Year 1), FLUAD® Quadrivalent (Year 2), and Flublok Quadrivalent (Year 3). The study will measure changes in your body's antibody responses to these vaccines to see how well they work over time. To join, you must be 65 or older, able to speak and read English, weigh at least 110 lbs, and have received flu vaccines before without severe reactions. The study's status is currently unclear.

Study design
This is a single-arm study, meaning all 75 participants will receive the same sequence of interventions. It is an interventional study, but the phase is not specified.
What's involved
You would receive a flu vaccine each year for three years and provide blood samples at 16 visits over three years. Nasal swab and stool samples will also be collected at seven time-points.
Compensation
Not stated in the trial record.
Follow-up
Your antibody responses will be measured at Baseline, Day 35, and Day 180 after vaccination for each of the first three years.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT05518500

A Deep Longitudinal Analysis of Next Generation Influenza Vaccines in Older Adults

Active, Not Recruiting
PHASE4Ages 65+InterventionalBasic science
The Jackson Laboratory
~75 participants
Updated 2026-08-03 on ClinicalTrials.gov
What's tested:Flu Vaccine (Year 1)Flu Vaccine (Year 2)Flu Vaccine (Year 3)Flu Vaccine (Year 4)

At a glance

Recruiting sites
0 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Change in Antibody Responses to Influenza Vaccine Year One
Measured over Baseline, Day 35, Day 180
+3 more outcomes measured

Conditions

Aging
Influenza Vaccine
Dendritic Cell
Vaccine Response

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Aging

NCT05518500

Where you'd take part

This study runs at 1 site. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • UConn Health, Center On Aging

    Farmington, Connecticutno site contact published

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

Study leadership

  • George Kuchel, MD, FRCP · PRINCIPAL_INVESTIGATOR · UConn Center on Aging

Who to contact

This trial hasn't published a contact. View it on ClinicalTrials.gov

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Eligibility criteria

Inclusion

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

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

What this trial measures

  • Change in Antibody Responses to Influenza Vaccine Year OneBaseline, Day 35, Day 180

    In year one, healthy older participants will receive Fluzone Quadrivalent HD vaccine. Longitudinal blood samples will be collected and influenza-specific antibody responses will be assessed. Change in antibody response will be measured using Hemagglutination Inhibition (HAI) from baseline to day 35 and day 180.

  • Change in Antibody Responses to Influenza Vaccine Year TwoBaseline, Day 35, Day 180

    In year two, healthy older participants will receive FLUAD vaccine. Longitudinal blood samples will be collected and influenza-specific antibody responses will be assessed. Change in antibody response will be measured using Hemagglutination Inhibition (HAI) from baseline to day 35 and day 180.

  • Change in Antibody Responses to Influenza Vaccine Year ThreeBaseline, Day 35, Day 180

    In year three, healthy older participants will receive Flublok Quadrivalent vaccine. Longitudinal blood samples will be collected and influenza-specific antibody responses will be assessed. Change in antibody response will be measured using Hemagglutination Inhibition (HAI) from baseline to day 35 and day 180.

  • Change in Antibody Responses to Influenza Vaccine Year FourBaseline, Day 35, Day 180

    In year four, healthy older participants will receive Fluzone® High-Dose Trivalent vaccine. Longitudinal blood samples will be collected and influenza-specific antibody responses will be assessed. Change in antibody response will be measured using Hemagglutination Inhibition (HAI) from baseline to day 35 and day 180.