B Cell and Antibody Response to Seasonal Influenza Vaccines in Younger and Older Adults

B Cell and Antibody Response to Seasonal Influenza Vaccines in Younger and Older Adults (NCT04101838) is a Phase 4 interventional studying Influenza, sponsored by University of Alabama at Birmingham. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

What Stage of Research Is This?

Phase 4 studies happen after a treatment has been approved by the FDA. They monitor long-term safety, real-world effectiveness, and any rare side effects that only emerge in larger populations over longer periods. Phase 4 results sometimes lead to label changes, additional warnings, or — rarely — withdrawal of approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 50 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Influenza subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: - Participation in ancillary clinical research study - Able to give willing to sign a consent form - Age 18-50 years old for Arm 1 and Arm 2 - Age 65-80 years old for Arm 3, Arm 4, and Arm 5 - Weight of at least 110 lbs as determined by self-reporting Who Should NOT Join This Trial: - Inability to give willing to sign a consent form - Refusal or inability to have blood drawn or participate in study procedures - Previous adverse reaction to influenza vaccine or medical history contraindicated for receiving influenza vaccine, including but not limited to: 1. History of Guillain-Barre Syndrome 2. History of egg allergy 3. History of gelatin allergy 4. History of moderate to severe illness with or without fever within 6 weeks of receipt of influenza vaccine - Previous receipt of influenza vaccine outside of study within current season - Bleeding disorder diagnosed by a doctor (eg, factor deficiency, coagulopathy, or platelet disorder requiring special precautions) - Participant has any medical, psychiatric, or social condition, or occupational or other responsibility that, in the judgement of the investigator would interfere with, or serve as a contraindication to the planned procedure(s). - These following criteria are used for scientific reasons, and not safety reasons. Specifically, the criteria are used to obtain a population that is healthy and less likely to have conditions that may influence the immune system: 1. No recent respiratory infections in the past 4 weeks at time of vaccination 2. Malignancy 3. Evidence of Inflammation: Systemic Lupus Erythematosis, Rheumatoid Arthritis, Polymyositis, Dermatomyositis, Scleroderma, Crohn's Disease, Ulcerative Colitis. 4. Lymphoproliferative Disorder 5. Known weakened immune system 6. Myocardial Infarction \<6 months 7. Cerebral Vascular Accident 8. Peripheral Vascular Disease- recannulation \<6months 9. Cardiac Insufficiency - congestive heart failure ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: * Participation in ancillary clinical research study * Able to give informed consent * Age 18-50 years old for Arm 1 and Arm 2 * Age 65-80 years old for Arm 3, Arm 4, and Arm 5 * Weight of at least 110 lbs as determined by self-reporting Exclusion Criteria: * Inability to give informed consent * Refusal or inability to have blood drawn or participate in study procedures * Previous adverse reaction to influenza vaccine or medical history contraindicated for receiving influenza vaccine, including but not limited to: 1. History of Guillain-Barre Syndrome 2. History of egg allergy 3. History of gelatin allergy 4. History of moderate to severe illness with or without fever within 6 weeks of receipt of influenza vaccine * Previous receipt of influenza vaccine outside of study within current season * Bleeding disorder diagnosed by a doctor (eg, factor deficiency, coagulopathy, or platelet disorder requiring special precautions) * Participant has any medical, psychiatric, or social condition, or occupational or other responsibility that, in the judgement of the investigator would interfere with, or serve as a contraindication to the planned procedure(s). * These following criteria are used for scientific reasons, and not safety reasons. Specifically, the criteria are used to obtain a population that is healthy and less likely to have conditions that may influence the immune system: 1. No recent respiratory infections in the past 4 weeks at time of vaccination 2. Malignancy 3. Evidence of Inflammation: Systemic Lupus Erythematosis, Rheumatoid Arthritis, Polymyositis, Dermatomyositis, Scleroderma, Crohn's Disease, Ulcerative Colitis. 4. Lymphoproliferative Disorder 5. Known Immunodeficiency 6. Myocardial Infarction \<6 months 7. Cerebral Vascular Accident 8. Peripheral Vascular Disease- recannulation \<6months 9. Cardiac Insufficiency - congestive heart failure 10. Hypertension with increased blood urea nitrogen (BUN) 11. Renal Failure 12. Dementia 13. Alcoholism (defined as \>17 drinks/week) 14. Drug Abuse (excluding marijuana) 15. HIV positive 16. History of hepatitis 17. History of immunization within 4 weeks of study participation or plan to receive non- IIV vaccination within 4 weeks of receiving IIV 18. Moderate to severe illness at time of enrollment * Donations of blood in the 8 weeks prior to enrollment which, combined with expected volumes to be drawn for this study, would exceed 450 mL in an 8 week period. * Current pregnancy at time of enrollment or pregnancy within last 4 months * Active or planned breastfeeding during study participation * Psychiatric condition that precludes compliance with the protocol. Specifically excluded are persons with psychoses within the past 3 years, ongoing risk for suicide, or history of suicide attempt or gesture within the past 3 years.

Treatments Being Tested

DRUG

Fluzone

inactivated seasonal influenza vaccine

DRUG

Flucelvax

inactivated seasonal influenza vaccine

DRUG

Fluzone High-Dose

inactivated seasonal influenza vaccine

DRUG

Fluad

inactivated seasonal influenza vaccine

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

University of Alabama at Birmingham

Birmingham, Alabama, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT04101838), the sponsor (University of Alabama at Birmingham), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT04101838 clinical trial studying?

This study will examine how various FDA-approved seasonal influenza vaccine types, used in a manner consistent with their approved use, impact the characteristics of influenza specific antibodies in humans, and how these responses differ based on age and prior immunization history. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT04101838?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT04101838?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT04101838. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT04101838. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.