A Study to Learn About mRNA Vaccines Against Influenza in Adults
A PHASE 2, RANDOMIZED, DOUBLE-BLIND, CLINICAL STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF MRNA VACCINES AGAINST INFLUENZA IN ADULTS 18 YEARS OF AGE AND OLDER
1 other identifier
interventional
770
1 country
15
Brief Summary
The purpose of this study is to learn about safety in participants taking the study vaccine (mRNA-based vaccine) and the ability of the study vaccine to trigger the body's immune response, targeting the flu virus (influenza virus). This study is seeking healthy participants 18 years of age or older. All participants in this study will receive only 1 dose in their arm, to deliver one of the experimental flu vaccines or one of the approved flu vaccines used for comparison. Participants will take part in this study for about 6 months, and participants will need to visit the study site at least 3 times. A blood sample will be taken at each of the 3 planned study visits and a swab from inside the nose will be taken at the first study visit.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for phase_2
Started Feb 2026
Shorter than P25 for phase_2
15 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
February 19, 2026
CompletedStudy Start
First participant enrolled
February 23, 2026
CompletedFirst Posted
Study publicly available on registry
February 25, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
June 22, 2027
ExpectedStudy Completion
Last participant's last visit for all outcomes
June 22, 2027
May 6, 2026
May 1, 2026
1.3 years
February 19, 2026
May 4, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (5)
Percentage of participants reporting prespecified local reactions following vaccination
Within 7 days after vaccination
Percentage of participants reporting prespecified systemic events following vaccination.
Within 7 days after vaccination
Percentage of participants reporting adverse events (AEs) following vaccination.
Within 1 month after vaccination
Percentage of participants reporting serious adverse events (SAEs) following vaccination.
Within 6 months after vaccination
Percentage of participants reporting newly diagnosed chronic medical conditions (NDCMCs) following vaccination.
Within 6 months after vaccination
Secondary Outcomes (3)
Geometric Mean Titer (GMT) of Anti-Influenza Antibody Levels to each of the influenza antigens of the vaccine.
Before vaccination and at 4 weeks after vaccination
Geometric Mean Fold Rise (GMFR) of Anti-Influenza Antibody Levels to each of the influenza antigens of the vaccine
Before vaccination to 4 weeks after vaccination
Percentage of participants with satisfactory antibody response to the vaccine.
Before vaccination to 4 weeks after vaccination
Study Arms (7)
A
EXPERIMENTALmRNA influenza vaccine candidate #1 as a single intramuscular (IM) injection on Day 1.
B
EXPERIMENTALmRNA influenza vaccine candidate #2 as a single IM injection on Day 1.
C
EXPERIMENTALmRNA influenza vaccine candidate #3 as a single IM injection on Day 1.
D
EXPERIMENTALmRNA influenza vaccine candidate #4 as a single IM injection on Day 1.
E
EXPERIMENTALmRNA influenza vaccine candidate #5 as a single IM injection on Day 1.
F
EXPERIMENTALmRNA influenza vaccine candidate #6 as a single IM injection on Day 1.
G
ACTIVE COMPARATORLicensed influenza vaccine (TIV1 or TIV2) as a single IM injection.
Interventions
Eligibility Criteria
You may not qualify if:
- Tested positive for influenza ≤5 months (150 days) prior to Visit 1 (Day 1).
- Vaccination with any investigational or licensed influenza vaccine ≤5 months (150 days) before Visit 1 (Day 1).
- Receipt of antiviral therapies for influenza (eg, Tamiflu) ≤5 months (150 days) prior to Visit 1 (Day 1).
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- Pfizerlead
Study Sites (15)
AMR Clinical
Mobile, Alabama, 36608, United States
Diablo Clinical Research, LLC d/b/a Flourish Research
Walnut Creek, California, 94598, United States
Clinical Research Consulting, LLC
Milford, Connecticut, 06460, United States
George Washington Medical Faculty Associates
Washington D.C., District of Columbia, 20037, United States
Indago Research & Health Center, Inc
Hialeah, Florida, 33012, United States
Palm Springs Community Health Center
Miami Lakes, Florida, 33014, United States
Clinical Research Atlanta
Stockbridge, Georgia, 30281, United States
East-West Medical Research Institute
Honolulu, Hawaii, 96814, United States
AMR Clinical
Kansas City, Missouri, 64114, United States
Rochester Clinical Research, LLC
Rochester, New York, 14609, United States
DM Clinical Research - Philadelphia
Philadelphia, Pennsylvania, 19107, United States
SMS Clinical Research LLC
Mesquite, Texas, 75149, United States
DM Clinical Research
Tomball, Texas, 77375, United States
J. Lewis Research, Inc. / Foothill Family Clinic
Salt Lake City, Utah, 84109, United States
Charlottesville Medical Research Center, LLC
Charlottesville, Virginia, 22911, United States
Related Links
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- STUDY DIRECTOR
Pfizer CT.gov Call Center
Pfizer
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 2
- Allocation
- RANDOMIZED
- Masking
- QUADRUPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
- Purpose
- PREVENTION
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
February 19, 2026
First Posted
February 25, 2026
Study Start
February 23, 2026
Primary Completion (Estimated)
June 22, 2027
Study Completion (Estimated)
June 22, 2027
Last Updated
May 6, 2026
Record last verified: 2026-05
Data Sharing
- IPD Sharing
- Will share
Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.