Age-Associated Differences in Germinal Center Responses to Influenza and Rabies Vaccination in Humans

October 27, 2026 updated by: Washington University School of Medicine

This study is being done to better understand how the immune system responds to vaccination against influenza and rabies. Researchers want to study how immune responses develop and change over time in the blood and in the lymph nodes that drain the vaccination site, following vaccination with two vaccines licensed by the U.S. Food and Drug Administration (FDA): the seasonal trivalent influenza vaccine (TIV) and the rabies vaccine (RabAvert). By studying these samples, researchers hope to learn how the body produces high-quality, long-lasting antibody and memory immune responses after vaccination. The study will also compare immune responses in younger adults to immune responses in older adults, because prior research suggests that the immune system's ability to respond to vaccination weakens with age.

Study Overview

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

    • Missouri
      • St Louis, Missouri, United States, 63110
        • Recruiting
        • Washington University
        • Contact:
        • Contact:
        • Principal Investigator:
          • Patrick Olson, MD
        • Sub-Investigator:
          • Rachel Presti, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Healthy participants 18 to 40 years of age or ≥65 years of age.
  2. Able to understand and give informed consent.
  3. Willing to receive RabAvert vaccine.
  4. Willing to receive TIV (trivalent influenza vaccine).
  5. In stable health, as determined by medical history and targeted physical exam related to this history.
  6. Willing to give blood and optional lymph node FNA (fine needle aspiration) samples.

Exclusion Criteria:

  1. Has a history of severe local or systemic reactions to any vaccination.
  2. Has a history of severe allergic reaction to any component of the rabies or influenza vaccines.
  3. Has a history of prior rabies vaccination, receipt of rabies post-exposure prophylaxis or rabies immunoglobulin, or known or suspected prior exposure to rabies virus.
  4. Has received any influenza vaccines ≤ 180 days prior to the day of injection (Day 1).
  5. Has a current or previous diagnosis of immunocompromising condition to include human immunodeficiency virus, immune-mediated disease requiring immunosuppressive treatment, or other immunosuppressive condition.
  6. Has received systemic immunosuppressants or immune-modifying drugs for > 14 days in total within 6 months prior to Screening (for corticosteroids ≥ 10 mg/day of prednisone equivalent) or is anticipating the need for immunosuppressive treatment at any time during participation in the study.
  7. Is acutely ill or febrile (temperature >38.0 C [100.4F] less than 72 hours prior to or at the Day 1 visit. Participants who meet this criterion may be rescheduled.
  8. Currently has symptomatic acute or unstable chronic disease requiring medical or surgical care, to include significant change in therapy or hospitalization, at the discretion of the investigator.
  9. History of excessive alcohol consumption, drug abuse, psychiatric conditions, social conditions or occupational conditions that in the opinion of the investigator would preclude compliance with the study.
  10. Has received any vaccine ≤ 28 days prior to the injection (Day 1) or plans to receive a vaccine within 28 days before or after the study injection. These participants may be rescheduled.
  11. Pregnant women and nursing mothers or women who are planning to become pregnant for the study duration.
  12. Have donated blood, blood products or bone marrow within 30 days before study vaccination, plan to donate blood at any time during the duration of participant study participation, or plan to donate blood within 30 days after the last blood draw.
  13. Any condition in the opinion of the investigator that would interfere with the proper conduct of the trial.
  14. Unwilling to use an effective method of contraception if you are of childbearing potential.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Vaccination

Standard, seasonal flu vaccine

Standard, seasonal flu vaccines

Rabies vaccine for pre-exposure

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Rabies-specific antibody titers at day 29 compared to pre-vaccination baseline.
Time Frame: From vaccination day 1 to day 29
From vaccination day 1 to day 29

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 25, 2026

Primary Completion (Estimated)

February 1, 2027

Study Completion (Estimated)

September 25, 2027

Study Registration Dates

First Submitted

October 20, 2026

First Submitted That Met QC Criteria

October 27, 2026

First Posted (Actual)

November 3, 2026

Study Record Updates

Last Update Posted (Actual)

November 3, 2026

Last Update Submitted That Met QC Criteria

October 27, 2026

Last Verified

October 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The data to be generated and shared from this proposal will include clinical data with low-risk for identification, clinical from patients from human cohorts (described in more detail in the proposal) and a wealth of immunological data generated from assays performed on the clinical specimens derived from these subjects. The types of data to be uploaded include mainly .xls(x) or fasta files but also potentially .pdf, .doc(x), and .txt files

IPD Sharing Time Frame

Data will be deposited in the ImmPort shared data base, National Center for Biotechnology Information (NCBI), (GenBank, SRA, and dbGaP), MassIVE, PDB or EMDB data repositories. Each study deposited in ImmPort, PDB, and EMBD will be assigned a permanent digital object identifier (DOI) that will be cited in each publication. Each study or sequence(s) deposited in GenBank, SRA, or dbGaP will be assigned a permanent accession number that also will be cited in each publication. These persistent unique identifiers are searchable on Google and/or Pubmed. Each proteomic study deposited in MassIVE will be assigned a permanent ProteomeXchange accession that will be cited in each publication and is searchable on the MassIVE website. All of the data repositories to be used require rich metadata to be submitted along with each dataset to ensure that data is easy to find, access, and identify.

IPD Sharing Access Criteria

Data deposited on GenBank, SRA, MassIVE, PDB or EMDB will not be controlled and will be accessible for free download by the wider community. For data in ImmPort, users will need to register and agree to a Data Use Agreement prior to free download. Summaries of studies and the contents of measured variables deposited on dbGaP will be made public, while access to individual-level data will require authorization.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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