Flu Infection at UPHS

June 2, 2026 updated by: University of Pennsylvania

Evaluating Immune Imprinting in the Context of Influenza Virus Infections

Cellular and humoral immune responses in individuals with active influenza infection will be assessed. Each year, up to 50 participants will be enrolled. The investigators hypothesize that influenza infection will elicit mostly memory immune responses rather than de novo immune responses to infection.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Using samples collected from individuals after influenza virus vaccination, the investigators have shown that immune cells primed by previous influenza exposures are recruited to produce antibodies against newer viral strains. The investigators previous work indicate that the majority of the immune cells that respond to influenza vaccination are from the memory compartment, suggesting that 'immune imprinting' greatly affects the specificity of antibodies elicited by influenza vaccines. It remains less clear how prior influenza virus exposures impact immunity elicited by influenza virus infections. Compared to vaccinated individuals, it is more difficult to enroll influenza virus infected patients and track their immune responses over time. Viral antigens can persist for longer amounts of time following influenza virus infections relative to influenza vaccinations. It is therefore possible that influenza virus infections more efficiently prime de novo immune responses compared to influenza virus vaccinations. In this study, the investigators will longitudinally collect serum, PBMC, and respiratory samples from influenza virus-infected individuals from the University of Pennsylvania Health System characterize the cellular and humoral immune responses elicited by influenza virus infections.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
50

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

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Recruiting
        • Penn Presbyterian Medical Center
        • Contact:
          • Tachianna Griffiths

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Up to 50 influenza virus-infected participants who have tested positive for influenza virus infection within the University of Pennsylvania Health System will be enrolled in the study. Potential candidates will be in the Emergency Department with influenza-like symptoms and will be eligible once the eligibility criteria are met.

Description

Inclusion Criteria:

  1. Provision of signed and dated informed consent form
  2. Stated willingness to comply with all study procedures and availability for the duration of the study
  3. Aged 18 years and older
  4. Influenza positive test result performed within the University of Pennsylvania Health System

Exclusion Criteria:

  1. Known latex allergy
  2. Immunosuppression as a result of an underlying illness or treatment with immunosuppressive or cytotoxic drugs, or use of anticancer chemotherapy or radiation therapy within the preceding 36 months
  3. Pregnancy due to the volume of blood collected in this study
  4. Treatment with immunoglobulin or another blood product within the 3 months prior to enrollment in this study
  5. Any neoplastic disease (excluding non-melanoma skin cancer or prostate cancer that is stable in the absence of therapy) or a history of any hematological malignancy ("active" is defined as having received treatment within the past 5 years)
  6. Known acute or chronic medical condition that, in the opinion of the investigator or appropriate sub-investigator, would interfere with the evaluation of immune responses
  7. Intends to donate blood during the study period
  8. A known human immunodeficiency virus, hepatitis B, or hepatitis C infection
  9. Any condition that would, in the opinion of the site investigator, place the subject at an unacceptable risk of injury or render the subject unable to meet the requirements of the protocol
  10. Prolonged inpatient hospitalization that disrupts or interferes with study procedures.
  11. Weigh less than 110lbs

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

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Effect of influenza virus infection on neutralizing antibody titers to contemporary and historical influenza virus strains
Time Frame: 2 years
The investigators will compare neutralizing antibodies in sera, plasma, and nasal swab samples against the influenza strain that each participant is infected with as well as historical and recently circulating influenza virus strains. Antibody titers between different strains will be compared to understand if memory or de novo immune responses are generated following influenza infection based on inferred influenza exposure history.
2 years

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Differences in binding antibodies against historical and contemporary influenza virus strains in individuals following influenza virus infection
Time Frame: 2 years
The investigators will compare binding antibodies in sera, plasma, and nasal swab samples against the influenza strain that each participant is infected with as well as historical and recently circulating influenza virus strains. Antibody titers between different strains will be compared to understand if memory or de novo immune responses are generated following influenza infection based on inferred influenza exposure history.
2 years
Characterize B cell responses to influenza following influenza virus infection
Time Frame: 2 years
Influenza specific B cells will be identified in PBMC samples and their specificity and functionality to different influenza virus strains will be assessed to understand how influenza infection influences the generation of memory and de novo immune responses.
2 years
Characterize T cell responses to influenza following influenza virus infection
Time Frame: 2 years
T cells specific to influenza will be identified in PBMC samples and their specificity and functionality to different influenza virus strains will be assessed to understand how influenza infection influences the generation of memory and de novo immune responses.
2 years

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Pennsylvania

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Allergy and Infectious Diseases (NIAID)
Stanford University

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 27, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 30, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 29, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 29, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 4, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 3, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 2, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 857436
  • 75N93021C00015-P00012-9999-1 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Protocol and statistical analysis plan may need to be shared for publication.

IPD Sharing Time Frame

At publication

IPD Sharing Access Criteria

Per journal publication policy

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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