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

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: Not yet recruiting
• Conditions: Mucosal Immune Response to Influenza Vaccination
• Intervention / Treatment: Biological: FluMist (Live Attenuated Influenza Vaccine)

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: Interventional
• Enrollment (Estimated): 20
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Shanna H Graves, AAS; Phone Number: 205-975-2845; Email: shannagraves@uabmc.edu

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35294
      • University of Alabama at Birmingham
      • Contact: Shanna H Graves, AAS; Phone Number: 205-975-2845; Email: shannagraves@uabmc.edu

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

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

Outcome Measure	Measure Description	Time Frame
Change in Nasal Mucosal Immune Response Following FluMist 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

• Sponsor: University of Alabama at Birmingham
• Investigators: Principal Investigator: Kevin S Harrod, PhD, UAB All Study (Central)

Study record dates

Study Major Dates

• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): June 30, 2030
• Study Completion (Estimated): June 30, 2031

Study Registration Dates

• First Submitted: July 21, 2026
• First Submitted That Met QC Criteria: July 21, 2026
• First Posted (Actual): July 24, 2026

Study Record Updates

• Last Update Posted (Actual): July 24, 2026
• Last Update Submitted That Met QC Criteria: July 21, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: FluMist, LAIV, influenza vaccine, mucosal immunity, nasal immune response, intranasal vaccine, healthy volunteers, nasal swab, proteomics
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; Orthomyxoviridae Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Influenza, Human; FluMist
• Other Study ID 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