NCT07177417

Characterizing the Human Airway Immune Response to FluMist Vaccination

EVax-3: Human Upper and Lower Airway Mucosal Immune Response to FluMist Vaccination

• Status: Recruiting
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 30 (estimated)
• Sponsor: Washington University School of Medicine · Academic / Other
• Sex: All
• Age: 18 Years – 40 Years
• Healthy volunteers: Accepted

Summary

The goal of this clinical trial is to measure the immune response in the blood, nose, and lungs after participants receive either the FDA-approved inactivated influenza vaccine or the FDA-approved intranasal FluMist vaccine. The study will evaluate immune responses in groups of healthy, non-pregnant, volunteers between the ages of 18 and 40. The main purpose of the study is to measure the change in influenza vaccine-specific antibodies in the lower lungs and nose between vaccination and 14 days after participants receive the vaccine. All participants will be randomized to receive one of the two seasonal flu vaccines and will have blood and back of the nose swabs collected throughout the study. Some study participants will choose to undergo optional bronchoscopy procedures and will be included in the part of the study looking at lower lung immune responses.

Detailed description

Study Design/Methodology: Prospective randomized controlled trial; Study Duration: 2 years; Number of Subjects: 30; Subject Participation Duration: 4 months; Description of Interventions: Eligible healthy participants who have not received a seasonal influenza vaccine within the past 9 months will complete written informed consent. Enrolled participants will be randomized to receive either an FDA-approved intramuscular seasonal egg-based inactivated influenza vaccine (IIV) (N=15) or the FDA-approved seasonal FluMist intranasal live attenuated influenza vaccine (N=15) on study day 0. Blood samples and nasopharyngeal swabs will be collected at the time of study enrollment (up to 45 days prior to vaccination) and on days 3±1, 7±2, 14±3, 28±5, and 90±14 post-vaccination. Sixteen participants (N=8 in each vaccine group) will be enrolled for optional research bronchoscopy procedures. Research bronchoscopies will include bronchoalveolar lavage (BAL) and endobronchial biopsy (EBBx) sample collection. Research bronchoscopies will be performed prior to vaccination and on study days 14±3 and 90±14. Screening safety laboratory studies and screening chest x-ray imaging will be performed on subjects undergoing research bronchoscopies.

Conditions

• Healthy Young Adults
• Influenza Vaccines
• Influenza Vaccine Response

Interventions

Type	Name	Description
BIOLOGICAL	FluMist	intranasal administered live attenuated influenza vaccine
BIOLOGICAL	inactivated influenza vaccine	intramuscular administered inactivated influenza vaccine
PROCEDURE	bronchoscopy	bronchoscopy with bronchoalveolar lavage and endobronchial biopsy sampling

Timeline

• Start date: 2025-09-09
• Primary completion: 2026-09-01
• Completion: 2028-11-01
• First posted: 2025-09-17
• Last updated: 2025-09-17

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study