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Respiratory Syncytial VirusPhase 3NCT06060457

A Study to Evaluate the Safety and Immune Response of mRNA-1345, a Vaccine Targeting Respiratory Syncytial Virus (RSV), When Co-administered With a Fluzone HD, in Adults ≥65 Years of Age

A Phase 3 study testing mRNA-1345 and Fluzone HD in people with Respiratory Syncytial Virus, run by ModernaTX, Inc. at 34 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The main purpose of this study is to evaluate the safety and immunogenicity of mRNA-1345 RSV vaccine when coadministered with a high dose (HD) quadrivalent seasonal influenza vaccine (Fluzone HD) in adults ≥65 years of age. Read more about this study

Who is it for?
Ages 65 years and olderHealthy volunteers can take part
Conditions the study is for
Respiratory Syncytial Virus
What is being tested?
mRNA-1345 and Fluzone HD
Type of treatment
Injection or infusion
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
1,900 participants
Where
34 sitesUnited States
Study dates
25 Sep 2023to 7 Jun 2024
Phase
Phase 3
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 65 years and older
  • All sexes
  • Healthy volunteers accepted
  • Older adult

Who may be able to join

  • Participants may have one or more chronic medical diagnoses, but should be medically stable as assessed by:
  • Absence of changes in medical therapy within 60 days of Day 1 due to treatment failure or toxicity,
  • Absence of serious or significant medical events within 30 days of Day 1, and
  • Absence of known, current, and life-limiting diagnoses which, in the opinion of the Investigator, would make completion of the protocol unlikely.
  • A participant assigned female at birth is eligible to participate if they are postmenopausal or not a person of childbearing potential.

Who cannot join

  • Close contact with someone with laboratory-confirmed influenza and/or RSV infection or with someone who has been treated with antiviral therapies for influenza (for example, Tamiflu®) within the past 5 days prior to Day 1.
  • Reported history of congenital or acquired immunodeficiency, immunosuppressive condition or immune-mediated disease, asplenia, or recurrent severe infections.
  • Participant has tested positive for influenza or RSV by local health authority-approved testing methods ≤6 months prior to Day 1.
  • Participant has received or plans to receive any vaccine authorized or approved by a local health agency ≤28 days prior to study injections (Day 1 and Day 22) or plans to receive a vaccine authorized or approved by a local health agency within 28 days after study injections.
  • Participant has received a seasonal influenza vaccine or any other investigational influenza vaccine ≤6 months prior to Day 1.
  • Participant has received any RSV vaccine (authorized/approved by local health agency or investigational) prior to Day 1.
  • Note: Other protocol-defined inclusion and/or exclusion criteria may apply.

Trial locations and contacts

34 sites in 1 country.

34 sites in 1 country

United States34 sites

  • Synexus AES - Akron

    Akron, Ohio, 44311

  • Velocity Clinical Research-Baton Rouge

    Baton Rouge, Louisiana, 70809

  • Bingham Memorial Hospital

    Blackfoot, Idaho, 83221

  • DM Clinical Research - Brookline

    Brookline, Massachusetts, 02445

  • Centricity Research

    Columbus, Ohio, 43213

  • West Coast Research LLC

    Dublin, California, 94568

  • Delricht Research at Gulfport Memorial

    Gulfport, Mississippi, 39503

  • Delricht Moyer

    Hendersonville, Tennessee, 37075

  • Neoclinical Research

    Hialeah, Florida, 33016

  • DM Clinical Research - Houston

    Houston, Texas, 77065

  • Health Awareness INC

    Jupiter, Florida, 33458

  • Be Well Clinical Studies, LLC

    Lincoln, Nebraska, 68516

  • DELRICHT RESEARCH at ZOMNIR FAMILY MEDICINE

    McKinney, Texas, 75070

  • South Florida Research Center, Inc.

    Miami, Florida, 33135

  • Suncoast Research Associates, LLC

    Miami, Florida, 33173

  • Velocity Clinical Research-Norfolk

    Norfolk, Nebraska, 68701

  • Headlands Research - Orlando

    Orlando, Florida, 32819

  • DM Clinical Research - Philadelphia

    Philadelphia, Pennsylvania, 19107

  • DelRicht Research @ Neighborhood Health

    Prairieville, Louisiana, 70769

  • DM Clinical Research- River Forest

    River Forest, Illinois, 60305

  • Artemis Institute for Clinical Research

    Riverside, California, 92503

  • Peninsula Research Associates (PRA)

    Rolling Hills Estates, California, 90274

  • Acclaim Clinical Research

    San Diego, California, 92120

  • Scottsdale Clinical Trials

    Scottsdale, Arizona, 85258

  • Headlands Research, Inc.

    Scottsdale, Arizona, 85260

  • DM Clinical Research - Southfield

    Southfield, Michigan, 48076

  • Spartanburg Medical Research

    Spartanburg, South Carolina, 29303

  • Delricht Research

    Springfield, Missouri, 65807

  • Clinical Research Atlanta/Headlands

    Stockbridge, Georgia, 30281

  • Javara Inc. /Privia Medical Group Gulf Coast, PLLC

    Sugar Land, Texas, 77054

  • New Tampa Health, Inc

    Tampa, Florida, 33603

  • DM Clinical Research

    Tomball, Texas, 77375

  • Delricht Tate

    Tulsa, Oklahoma, 74133

  • Trial Management Associates, LLC

    Wilmington, North Carolina, 28403

Other trials in United States

About this study

Official title: A Phase 3, Randomized, Observer-Blind Study to Evaluate Safety, Tolerability, and Immunogenicity of mRNA-1345, an mRNA Vaccine Targeting Respiratory Syncytial Virus, When Coadministered With a High-Dose, Quadrivalent Seasonal Influenza Vaccine in Adults ≥65 Years of Age

The main purpose of this study is to evaluate the safety and immunogenicity of mRNA-1345 RSV vaccine when coadministered with a high dose (HD) quadrivalent seasonal influenza vaccine (Fluzone HD) in adults ≥65 years of age. The study will examine the impact of Fluzone HD on the immune response to mRNA-1345 against RSV-A and RSV-B, as well as the impact of mRNA-1345 on the immune response to Fluzone HD against 4 vaccine-matched Influenza A and B strains.

Being tested
Placebo, mRNA-1345, Fluzone HD
Keywords
Viral Diseases, Messenger RNA, Moderna, mRNA-1345, Respiratory syncytial virus, Vaccines, RSV Vaccine
Medical subject headings
Virus Diseases

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PlaceboBiological

    0.9% sodium chloride (normal saline) injection

  • mRNA-1345Biological

    Suspension for injection

  • Fluzone HDBiological

    Suspension for injection

Study groups in NCT06060457
Study groupRoleWhat they receive
Fluzone HD + mRNA-1345ExperimentalParticipants will receive Fluzone HD + mRNA-1345 by intramuscular (IM) injection on Day 1 followed by placebo by IM injection on Day 22.
Receives: Biological: Placebo; Biological: mRNA-1345; Biological: Fluzone HD
Fluzone HD Followed by mRNA-1345ExperimentalParticipants will receive Fluzone HD + placebo by IM injection on Day 1 followed by mRNA-1345 by IM injection on Day 22.
Receives: Biological: Placebo; Biological: mRNA-1345; Biological: Fluzone HD

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs) Within 7 Days After Day 1 Injection

    Solicited ARs were collected in an electronic diary (eDiary). Local ARs: injection site pain, erythema (redness), swelling/induration (hardness); and axillary (underarm) swelling or tenderness ipsilateral to the side of injection. Systemic ARs: fever, headache, fatigue, myalgia, arthralgia, nausea/vomiting, and chills. Note, not all solicited ARs were considered adverse events (AEs). Investigator reviewed whether the solicited AR was also to be recorded as an AE. A Summary of serious AEs (SAEs) and nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

    Measured: Within 7 days after Day 1 injection

  2. Number of Participants With Solicited Local and Systemic ARs Within 7 Days After Day 22 Injection

    Solicited ARs were collected in an eDiary. Local ARs: injection site pain, erythema (redness), swelling/induration (hardness); and axillary (underarm) swelling or tenderness ipsilateral to the side of injection. Systemic ARs: fever, headache, fatigue, myalgia, arthralgia, nausea/vomiting, and chills. Note, not all solicited ARs were considered AEs. Investigator reviewed whether the solicited AR was also to be recorded as an AE. A Summary of SAEs and nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

    Measured: Within 7 days after Day 22 injection

  3. Number of Participants With Unsolicited Adverse Events (AEs) Up to 21 Days After Day 1 Injection

    An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related. Any abnormal laboratory test result (hematology, clinical chemistry, or prothrombin time [PT]/partial thromboplastin time [PTT]) or other safety assessment (for example, electrocardiogram, radiological scan, vital sign measurement), including one that worsened from baseline and was considered clinically significant in the medical and scientific judgment of the Investigator was recorded as an AE. A summary of SAEs and all nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

    Measured: Up to 21 days after Day 1 injection

  4. Number of Participants With Unsolicited AEs Up to 21 Days After Day 22 Injection

    An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related. Any abnormal laboratory test result (hematology, clinical chemistry, or PT/PTT) or other safety assessment (for example, electrocardiogram, radiological scan, vital sign measurement), including one that worsened from baseline and was considered clinically significant in the medical and scientific judgment of the Investigator was recorded as an AE. A summary of SAEs and all nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

    Measured: Up to 21 days after Day 22 injection

  5. Number of Participants With Medically Attended Adverse Events (MAAEs), Adverse Events of Special Interest (AESIs), Serious Adverse Events (SAEs), and AEs Leading to Discontinuation

    A MAAE is an AE that leads to an unscheduled visit to a healthcare practitioner. An AESI is an AE (serious or nonserious) of scientific and medical concern specific to the Sponsor's product or program, for which ongoing monitoring and immediate notification by the Investigator to the Sponsor are required. An SAE was defined as any AE that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in disability, was a congenital anomaly/birth defect, or was an important medical event. A summary of SAEs and all nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

    Measured: Day 1 through Day 202

  6. Geometric Mean Titer (GMT) of Serum Respiratory Syncytial Virus Subtype A (RSV-A) and Respiratory Syncytial Virus Subtype B (RSV-B) Neutralizing Antibodies (nAbs)

    Antibody values reported as below lower limit of quantification (LLOQ) were replaced by 0.5*LLOQ. Values greater than the upper limit of quantification (ULOQ) were replaced by the ULOQ. LLOQ was 13 international units (IU)/milliliter (mL) and ULOQ was 259061 IU/mL for RSV-A. LLOQ was 10 IU/mL and ULOQ was 112476 for RSV-B.

    Measured: Day 22 (for Arm 1) and Day 43 (for Arm 2)

  7. GMT of Serum Anti-Hemagglutination (HA) Ab Level, as Measured by Hemagglutination Inhibition (HAI) Assay

    Influenza A strains included H1N1 and H3N2 and influenza B strains included Austria and Phuket strains. Antibody values reported as below LLOQ were replaced by 0.5*LLOQ. Values greater than the ULOQ were replaced by the ULOQ. LLOQ was 10 and ULOQ was 2560 for Influenza A. LLOQ was 10 and ULOQ was 640 for Influenza B.

    Measured: Day 22

Secondary outcomes (5)

  1. Percentage of Participants With Seroresponse for RSV-A and RSV-B nAbs, as Measured by HAI Assay

    Seroresponse at a participant level was defined as a change from below the LLOQ to equal or above 4 * LLOQ, or at least a 4-fold increase if baseline was equal to or above the LLOQ. LLOQ was 13 IU/mL and ULOQ was 259061 IU/mL for RSV-A. LLOQ was 10 IU/mL and ULOQ was 112476 for RSV-B.

    Measured: Baseline to Day 22 (for Arm 1) or Day 43 (for Arm 2)

  2. Geometric Mean Fold-Rise (GMFR) of Postinjection RSV-A and RSV-B nAbs Antibodies for Influenza, as Measured by HAI Assay

    95% CI for GMFR was calculated based on the t-distribution of the differences in the log-transformed values between analysis timepoint and baseline, then back transformed to the original scale for presentation.

    Measured: Day 22 (for Arm 1) or Day 43 (for Arm 2)

  3. Percentage of Participants With ≥2-fold Increase in RSV-A and RSV-B nAbs

    ≥2-fold increase from baseline at participant level was defined as a change from below the LLOQ to equal or above 2 * LLOQ, or at least a 2-fold increase if baseline was equal to or above the LLOQ. LLOQ was 13 IU/mL and ULOQ was 259061 IU/mL for RSV-A. LLOQ was 10 IU/mL and ULOQ was 112476 for RSV-B.

    Measured: Day 22 (Arm 1) or Day 43 (Arm 2)

  4. Percentage of Participants With Seroconversion, as Measured by HAI Assay

    Influenza A strains included H1N1 and H3N2 and influenza B strains included Austria and Phuket strains. Seroconversion at a participant level was defined as a titer ≥1:40 if baseline is < 1:10 or at least a 4-fold increase from baseline if baseline was ≥1:10. Antibody values reported as below LLOQ were replaced by 0.5*LLOQ. Values greater than the ULOQ were replaced by the ULOQ. LLOQ was 10 and ULOQ was 2560 for Influenza A. LLOQ was 10 and ULOQ was 640 for Influenza B.

    Measured: Day 22

  5. GMFR of Serum Ab Level, as Measured by HAI Assay

    95% CI for GMFR was calculated based on the t-distribution of the differences in the log-transformed values between analysis timepoint and baseline, then back transformed to the original scale for presentation.

    Measured: Day 22

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted29 Sep 2023
  2. Study start25 Sep 2023
  3. Primary completion7 Jun 2024
  4. Study completion7 Jun 2024

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Sequential
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
1,900 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06060457
Sponsor's protocol ID
mRNA-1345-P304
Status last verified
Jul 2025
First submitted
23 Sep 2023
Last updated
30 Jul 2025
FDA-regulated drug
Yes
FDA-regulated device
No

Publications

  • Comstock E, Fogarty C, Caso J, Vu J, Sinha A, Cao X, Chen H, Rushton L, Ma C, Priddy F. Coadministration of mRNA-1345 RSV vaccine with high-dose quadrivalent influenza vaccine in adults aged 65 and older: An observer-blinded, placebo-controlled, randomized, phase 3 trial. Hum Vaccin Immunother. 2026 Dec;22(1):2649335. doi: 10.1080/21645515.2026.2649335. Epub 2026 Apr 28.

    PubMed 42048601

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing mRNA-1345 and Fluzone HD in people with Respiratory Syncytial Virus, run by ModernaTX, Inc. at 34 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 30 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 34 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 30 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs) Within 7 Days After Day 1 Injection (time frame: Within 7 days after Day 1 injection). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06060457, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Jul 2025.

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