Clinical trial Recruiting at 1 site Early Phase 1 Interventional Ages 18 and up

Intradermal Flu Vaccine After All: Watching Immune Response in Skin and Blood

Official title: Characterization of Immune Response to Intradermal Influenza Vaccination

Run by Yale University · NCT07908329 · Data updated 2026-11-12

This study tests whether giving the seasonal flu shot into the skin (instead of muscle) changes the immune response in healthy adults, cancer patients about to start immunotherapy, and people with post-acute infection syndromes.

More Vaccine Reaction trials

Quick facts

PhaseEarly Phase 1
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment139 (estimated)
SponsorYale University
Academic / other
Drugs / interventionschemotherapy
Locations1 site (New Haven, Connecticut)
StatusRecruiting
StartedOctober 1, 2026
Main results expectedMay 2029
Study endsMay 2029
Registry record updatedNovember 2, 2026
Trial IDNCT07908329 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates are healthy adults aged 18-40, cancer patients eligible for influenza vaccination before immunotherapy, and adults with physician-diagnosed PAIS.

Probably not a fit

Patients with contraindications to intradermal vaccination or those outside the defined arms may not benefit.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a single-site, early-phase exploratory study to characterize local and systemic immune responses to intradermal influenza vaccination using an FDA-approved vaccine with a MicronJet device. Participants receive either intradermal or intramuscular vaccination depending on cohort, with immune features measured over time in skin and blood. Primary goals are to identify baseline correlates of the immune response and to describe how the skin’s inflammatory response evolves after vaccination. The study includes three arms: healthy adults, cancer patients awaiting checkpoint inhibitor therapy, and adults with PAIS such as long COVID or post-treatment Lyme disease. Optional stool samples may be collected to explore gut-related factors influencing immunity.

Why it matters

Potential benefit: If successful, the study could help tailor influenza vaccination approaches by linking skin and blood immune markers to vaccine responses.

How similar studies have gone: Prior work has explored intradermal vaccination and immune profiling, but this study combines skin-specific and systemic analyses in multiple patient groups, making its approach relatively novel.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion:

Healthy Arm:

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study, as well as have deidentified samples and data stored for future research.
* Able to proficiently speak, read, and write English.
* Male or female, aged 18-40 years old at time of initial enrollment

  a. Participant is allowed to participate in subsequent influenza seasons even if they will be \>40 years old.
* In good general health as evidenced by medical history

Cancer Arm:

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study, as well as have deidentified samples and data stored for future research.
* Able to proficiently speak, read, and write English.
* Deemed eligible to receive an influenza vaccine by their treating oncologist/oncological team. Their oncology team will also determine that the patient's participation in the study will not impact their clinical care or participation in other clinical trials.

PAIS Arm:

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study, as well as have deidentified samples and data stored for future research.
* Able to proficiently speak, read, and write English.
* Deemed eligible to receive an influenza vaccine by their referring provider.
* Documentation of infection (i.e. COVID-19, Lyme).

Exclusion:

Healthy Arm:

* CBC with differential, lymphocyte phenotyping with T, B, and natural killer cells (TBNK), complete metabolic panel, anti-CMV immunoglobulin (Ig) G and IgM, and/or anti-Epstein-Barr virus (EBV) antibody panel values outside of the Yale Department of Laboratory Medicine normal reference ranges and deemed clinically significant by the PI at the time of screening.
* Positive result for anti-HIV 1/2 antibody screening at the time of screening.
* Prior receipt of a current seasonal influenza vaccine (for the season of participation).
* History of allergy or hypersensitivity to any components of the study vaccine (e.g., egg protein).
* History of severe reactions to vaccines.
* Use of an oral glucocorticoid within the past 30 days.
* Receipt of a live-attenuated vaccine within the past 3 months.
* Receipt of any experimental vaccine.
* Receipt of any other type of vaccine (non-live and non-experimental, e.g., tetanus, diphtheria, and pertussis \[TDaP\]) within the past 3 months.
* Planned vaccination before day 100 after study vaccination.
* Current or recent use (within the past 90 days) of immunoglobulin therapy.
* Surgery within the past 8 weeks, or planned surgery before day 28.
* Current (within the past 30 days) treatment for active malignancy.
* Cancer chemotherapy in the past 2 years.
* Administration of any blood products within 90 days of the screening, or planned administration before day 100.
* History of parasitic, amebic, fungal, or mycobacterial infections within the past 1 year, with the exception of tinea pedis and onychomycosis.
* History of autoimmune or autoinflammatory disease.

  a. In particular skin-related (i.e. psoriasis, lichen planus, lupus, neutrophilic dermatoses, atopic dermatitis)
* History of keloids
* History of a bleeding disorder.
* Current use (within the past 30 days) of illicit drugs (per subject report), with the exception of marijuana.
* Current alcohol use disorders (criteria per Diagnostic and Statistical Manual of Mental Disorders, fifth edition), within the past 30 days.
* Serious, ongoing, uncontrolled infection within the past 30 days as per the judgement of the PI.
* History of Guillain-Barre syndrome (GBS).
* Body Mass Index ≥ 30.
* Known or suspected immunodeficiency within 1 year, including documented HIV infection.
* Pregnancy or planning to become pregnant during the study period. (Women of childbearing potential must have a negative urine or serum pregnancy test at screening.)
* Presence of conditions that, in the judgment of the PI, may put the individual at undue risk or compromise the scientific objectives of the study.

Co-enrollment guidelines: Co-enrollment in other trials is restricted, other than enrollment on observational studies. Consideration for co-enrollment in trials evaluating the use of a licensed medication will require the approval of the PI. Study staff should be notified of co-enrollment on any other protocol as it may require the approval of the PI.

Cancer Arm:

* CBC with differential, complete metabolic panel, anti-CMV immunoglobulin (Ig) G and IgM, and/or anti-Epstein-Barr virus (EBV) antibody panel values outside of the Yale Department of Laboratory Medicine normal reference ranges and deemed clinically significant by the PI at the time of screening.
* Positive result for Hepatitis B/C, tuberculosis, or anti-HIV 1/2 antibody at the time of screening.
* Prior receipt of a current seasonal influenza vaccine (for the season of participation) within the past 3 months.
* History of allergy or hypersensitivity to any components of the study vaccine (e.g., egg protein).
* History of severe reactions to vaccines.
* Active (episodes in the last year) autoimmune disease, such as but not limited to, vitiligo, hypothyroidism, multiple sclerosis, scleroderma, rheumatoid arthritis, and Grave's disease.
* History of keloids
* History of a bleeding disorder.
* Current use (within the past 30 days) of illicit drugs (per subject report), with the exception of marijuana.
* Current alcohol use disorders (criteria per Diagnostic and Statistical Manual of Mental Disorders, fifth edition), within the past 30 days.
* Serious, ongoing, uncontrolled infection within the past 30 days as per the judgement of the PI.
* History of Guillain-Barre syndrome (GBS).
* Pregnancy or planning to become pregnant during the study period. (Women of childbearing potential must have a negative urine or serum pregnancy test at screening.)
* Presence of conditions that, in the judgment of the PI, may put the individual at undue risk or compromise the scientific objectives of the study.

Co-enrollment guidelines: Co-enrollment in other trials is allowed, so that participants can consider other trials with potentially life-saving cancer therapies. Study staff should still be notified of co-enrollment to any other protocol.

PAIS Arm:

* CBC with differential, complete metabolic panel, anti-CMV immunoglobulin (Ig) G and IgM, and/or anti-Epstein-Barr virus (EBV) antibody panel values outside of the Yale Department of Laboratory Medicine normal reference ranges and deemed clinically significant by the PI at the time of screening.
* Positive result for Hepatitis B/C, tuberculosis, or anti-HIV 1/2 antibody at the time of screening.
* Prior receipt of a current seasonal influenza vaccine (for the season of participation) within the past 3 months.
* History of allergy or hypersensitivity to any components of the study vaccine (e.g., egg protein).
* History of severe reactions to vaccines.
* Active (episodes in the last year) autoimmune disease, such as but not limited to, vitiligo, hypothyroidism, multiple sclerosis, scleroderma, rheumatoid arthritis, and Grave's disease.
* History of keloids
* Bleeding disorder.
* Current use (within the past 30 days) of illicit drugs (per subject report), with the exception of marijuana.
* Current alcohol use disorders (criteria per Diagnostic and Statistical Manual of Mental Disorders, fifth edition), within the past 30 days.
* Serious, ongoing, uncontrolled infection within the past 30 days as per the judgement of the PI.
* History of Guillain-Barre syndrome (GBS).
* Pregnancy or planning to become pregnant during the study period. (Women of childbearing potential must have a negative urine or serum pregnancy test at screening.)
* Presence of conditions that, in the judgment of the PI, may put the individual at undue risk or compromise the scientific objectives of the study.

Co-enrollment guidelines: Co-enrollment in other trials is allowed. Study staff should still be notified of co-enrollment to any other protocol.

Where it's running

  • Church Street Research Unit
    New Haven, Connecticut, United States
    Recruiting

Study contacts

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How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.