Influenza HumanNCT06807840
Flu Infection at UPHS
An observational study of Influenza Human, run by University of Pennsylvania at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Influenza Human
- What is being tested?
- influenza virus infection
- How many people
- 19 participants
- Where
- 1 siteUnited States
- Study dates
- 27 Jan 2025to 29 Sep 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
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.
Who may be able to join
- Provision of signed and dated informed consent form
- Stated willingness to comply with all study procedures and availability for the duration of the study
- Aged 18 years and older
- Influenza positive test result performed within the University of Pennsylvania Health System
Who cannot join
- Known latex allergy
- 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
- Pregnancy due to the volume of blood collected in this study
- Treatment with immunoglobulin or another blood product within the 3 months prior to enrollment in this study
- 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)
- 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
Show all 11Show fewer
- Intends to donate blood during the study period
- A known human immunodeficiency virus, hepatitis B, or hepatitis C infection
- 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
- Prolonged inpatient hospitalization that disrupts or interferes with study procedures.
- Weigh less than 110lbs
Trial locations and contacts
1 site in 1 country.
United States1 site
Penn Presbyterian Medical Center
Philadelphia, Pennsylvania, 19104
About this study
Official title: 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.
Read the 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.
- Conditions
- Influenza Human
- Being tested
- influenza virus infection
- Keywords
- Flu Infection at UPHS
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
influenza virus infectionOther
Participants with active influenza virus infection will be enrolled in this study.
What is being measured
The primary outcome is the main question the study is designed to answer.
Effect of influenza virus infection on neutralizing antibody titers to contemporary and historical influenza virus strains
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.
Measured: 2 years
Secondary outcomes (3)
Differences in binding antibodies against historical and contemporary influenza virus strains in individuals following influenza virus infection
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.
Measured: 2 years
Characterize B cell responses to influenza following influenza virus infection
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.
Measured: 2 years
Characterize T cell responses to influenza following influenza virus infection
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.
Measured: 2 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Feb 2025
- Study start27 Jan 2025
- Primary completion29 Sep 2026
- Study completion29 Sep 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Influenza HumanStudies of the same condition, open and under way.
- More trials run by University of PennsylvaniaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Prospective
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Pennsylvania
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06807840
- Sponsor's protocol ID
- 857436
- Other IDs
- 75N93021C00015-P00012-9999-1
- Status last verified
- Oct 2026
- First submitted
- 29 Jan 2025
- Last updated
- 7 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Protocol and statistical analysis plan may need to be shared for publication.
Study at a glance
From the registry record, last updated by the sponsor on 7 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluating Immune Imprinting in the Context of Influenza Virus Infections
- ClinicalTrials.gov ID
- NCT06807840
- Acronym / sponsor ID
- 857436
- Conditions
- Influenza Human
- Keywords
- Flu Infection at UPHS
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 19 participants (actual)
- Lead sponsor
- University of PennsylvaniaUniversity, hospital or other
- Collaborators
- National Institute of Allergy and Infectious Diseases (NIAID), Stanford University
- Study start
- 27 Jan 2025 (actual)
- Primary completion
- 29 Sep 2026 (actual)
- Study completion
- 29 Sep 2026 (actual)
- First posted
- 4 Feb 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Observational model
- Case only
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (4 listed)
- Provision of signed and dated informed consent form
- Stated willingness to comply with all study procedures and availability for the duration of the study
- Aged 18 years and older
- Influenza positive test result performed within the University of Pennsylvania Health System
Key exclusion criteria (11 listed)
- Known latex allergy
- 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
- Pregnancy due to the volume of blood collected in this study
- Treatment with immunoglobulin or another blood product within the 3 months prior to enrollment in this study
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| influenza virus infectionParticipants with active influenza virus infection will be enrolled in this study. | Other | – |
Primary outcome
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.
3 secondary outcomes
Differences in binding antibodies against historical and contemporary influenza virus strains in individuals following influenza virus infection
Time frame: 2 years
Characterize B cell responses to influenza following influenza virus infection
Time frame: 2 years
Characterize T cell responses to influenza following influenza virus infection
Time frame: 2 years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Oct 2026.
- Individual participant dataSharing planned: Yes. Protocol and statistical analysis plan may need to be shared for publication.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Influenza Human, run by University of Pennsylvania at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Effect of influenza virus infection on neutralizing antibody titers to contemporary and historical influenza virus strains (time frame: 2 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Oct 2026.