How Healthy Adults Respond to the Nasal Flu Vaccine (MOSAIC)

July 21, 2026 updated by: Kevin Harrod, University of Alabama at Birmingham

Characterizing Local Mucosal Responses to Live Attenuated Influenza Vaccine in Healthy Adults

This study is looking at how the immune system in the nose responds after receiving the FluMist nasal flu vaccine in healthy adults. FluMist is an FDA-approved influenza vaccine that is given as a nasal spray.

Healthy volunteers aged 18 to 65 who do not have chronic medical conditions, do not smoke, and have not recently received a flu vaccine will be enrolled. Participants will have three study visits over approximately one week. At the first visit, participants will be screened, give informed consent, and receive the FluMist vaccine. Nasal swabs and a gentle saline nasal wash will be collected before vaccination and again at two and four days after vaccination.

The samples collected will be used to study changes in immune cells, proteins, and viral activity in the nose using laboratory techniques such as gene expression and protein analysis. This information may help researchers better understand how flu vaccines work at the site where infection begins and may support the development of improved vaccines in the future.

There is no direct medical benefit expected for participants. Participation is voluntary, and all study procedures will be performed by trained clinical staff.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet 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

This is a prospective interventional study evaluating mucosal immune and epithelial responses in healthy adults following administration of the FDA-approved live attenuated influenza vaccine (FluMist) given as an intranasal spray. Healthy volunteers aged 18 to 65 years who do not smoke and who meet eligibility criteria will be enrolled.

Participants will complete three study visits over approximately one week. At the first visit, informed consent, screening, baseline nasal swabs and nasal wash will be performed, followed by administration of FluMist. Follow-up nasal samples and safety assessments will be collected at approximately 2 and 4 days after vaccination.

Nasal samples will be analyzed using single-cell RNA sequencing, proteomics, and RT-qPCR to assess local immune, epithelial, and viral responses. Samples will be coded, stored under secure conditions, and retained for up to five years after study completion.

The objective of the study is to characterize early mucosal immune responses to FluMist vaccination and improve understanding of influenza vaccine-induced immunity at the site of infection.

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.
Interventional

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.
20

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

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 Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35294
        • University of Alabama at Birmingham
        • Contact:

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

Yes

Description

Inclusion Criteria:

  • Healthy adults aged 18 to 65 years
  • Non-smokers (no smoking or vaping within the past 6 months)
  • No chronic lung disease or significant chronic medical conditions
  • No current or recent (within 1 month) upper or lower respiratory infection
  • Able and willing to provide informed consent
  • Have not received the current seasonal influenza vaccine
  • Able to comply with study procedures and follow-up visits

Exclusion Criteria:

  • Age under 18 or over 65 years
  • Pregnancy or breastfeeding
  • Prisoners
  • Non-English speaking individuals
  • Immunocompromised individuals (including HIV/AIDS, immunosuppressive therapy, chemotherapy, or primary immunodeficiency)
  • Chronic medical conditions including asthma, chronic lung, liver, kidney, neurologic, hematologic, metabolic, or significant cardiovascular disease (except isolated hypertension)
  • History of chronic sinusitis or significant nasal allergies requiring frequent or daily treatment
  • Acute moderate or severe illness at time of enrollment, with or without fever
  • Receipt of influenza vaccine during the current season or within the past 2 weeks
  • Receipt of another live vaccine within 4 weeks prior to enrollment or planned during study period
  • Use of influenza antiviral medications (e.g., oseltamivir, zanamivir) within 48 hours prior to vaccination or planned use within 14 days after vaccination
  • History of severe allergic reaction to influenza vaccine or any component of FluMist (including egg allergy if applicable)
  • History of Guillain-Barré syndrome following influenza vaccination
  • Any condition that, in the opinion of the investigator, would interfere with study participation or interpretation of results

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
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.
Experimental: Healthy Adults Receiving Intranasal FluMist Vaccination
Participants in this single-arm study will receive the FDA-approved live attenuated influenza vaccine (FluMist) administered intranasally according to standard dosing guidelines. All participants will undergo nasal sampling procedures, including nasal swabs and nasal wash, at baseline prior to vaccination and at approximately 2 and 4 days following vaccination. Samples will be collected to evaluate temporal changes in mucosal immune and epithelial responses using molecular and proteomic analyses. No placebo or comparator intervention is used.
Biological: FluMist (Live Attenuated Influenza Vaccine)
FluMist is an FDA-approved live attenuated influenza vaccine administered as a nasal spray. Participants will receive a single standard dose of FluMist intranasally, with half the dose administered into each nostril by trained study personnel according to manufacturer instructions. The vaccine is used in this study to evaluate local mucosal and immune responses in the nasal cavity.

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
Change in Nasal Mucosal Immune Response Following FluMist Vaccination
Time Frame: Baseline through 4 days post-vaccination
This outcome measure evaluates changes in the nasal mucosal immune and epithelial response following administration of the intranasal live attenuated influenza vaccine (FluMist). Nasal swab and nasal wash samples will be collected at baseline (pre-vaccination) and at approximately 2 and 4 days post-vaccination. Samples will be analyzed using single-cell RNA sequencing, proteomics, and RT-qPCR to assess changes in immune cell populations, gene expression profiles, protein expression, and viral activity over time.
Baseline through 4 days post-vaccination

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 Alabama at Birmingham

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Kevin S Harrod, PhD, UAB All Study (Central)

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 (Estimated)

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.
October 1, 2026

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.
June 30, 2030

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.
June 30, 2031

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).
July 21, 2026

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.
July 21, 2026

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.
July 24, 2026

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.
July 24, 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.
July 21, 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.
  • IRB-300016968
  • UAB (Other Identifier: Anesthesiology)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared with other researchers. The study involves collection of sensitive health information and high-dimensional molecular data (including transcriptomic and proteomic analyses) linked to coded identifiers. To protect participant privacy and confidentiality, data will be stored in secure, HIPAA-compliant systems with access limited to IRB-approved study personnel. Only de-identified, aggregated results will be reported in publications and presentations.

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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