A Study of mRNA-1345, an mRNA Vaccine Targeting Respiratory Syncytial Virus, in Children 2 to <18 Years of Age at High Risk of Respiratory Syncytial Virus
A Phase 2, Randomized, Observer-blind Study to Evaluate the Safety, Reactogenicity, and Immunogenicity of mRNA-1345, an mRNA Vaccine Targeting Respiratory Syncytial Virus, in Children 2 to <18 Years of Age at High Risk of Respiratory Syncytial Virus Disease
2 other identifiers
interventional
349
2 countries
50
Brief Summary
Part A: The purpose is to evaluate the safety, reactogenicity, and immunogenicity of mRNA-1345 in children aged 2 to \<5 years (Cohort 1) and in children at high risk of respiratory syncytial virus (RSV) disease 5 to \<18 years of age (Cohort 2) to inform the dose level selection for the next phase of development (Phase 3). Part B: The purpose is to provide surveillance for RSV disease for the next RSV season (6 months after re-enrollment) and safety follow-up for Cohort 1 participants that were enrolled and dosed in Part A.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for phase_2
Started Oct 2023
50 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
October 18, 2023
CompletedFirst Posted
Study publicly available on registry
October 24, 2023
CompletedStudy Start
First participant enrolled
October 24, 2023
CompletedPrimary Completion
Last participant's last visit for primary outcome
June 27, 2025
CompletedStudy Completion
Last participant's last visit for all outcomes
June 27, 2025
CompletedResults Posted
Study results publicly available
August 18, 2026
CompletedAugust 18, 2026
July 1, 2026
1.7 years
October 18, 2023
June 11, 2026
July 27, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (4)
Part A (Cohorts 1 and 2): Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs)
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.
Up to 7 days post-injection
Part A (Cohorts 1 and 2): Number of Participants With Unsolicited Adverse Events (AEs)
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.
Up to 28 days post-injection
Part A (Cohorts 1 and 2): Number of Participants With Medically Attended AEs (MAAEs), Adverse Events of Special Interest (AESIs), Serious Adverse Events (SAEs), and AEs Leading to Study Discontinuation
A MAAE was an AE that led to an unscheduled visit to a healthcare practitioner. An AESI was 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.
Day 1 through end of Part A (Month 6)
Part B (Cohort 1): Number of Participants With RSV-RTD, Respiratory Syncytial Virus- Lower Respiratory Tract Disease (RSV-LRTD), Severe RSV-LRTD, Very Severe RSV-LRTD and RSV Hospitalization Classified by Clinical Assessment Team (CAT)
RSV-RTD: Runny nose or blocked nose or cough and confirmed RSV infection. RSV-LRTD: Cough or difficulty breathing (Based on Investigator's observation; difficulty breathing included signs of wheezing, stridor, tachypnoea, chest in-drawing or subcostal or intercostal retractions) and peripheral oxygen saturation (SpO2) \<95%, or respiratory rate (RR) increased and confirmed RSV infection. RSV Severe-LRTD: Meeting the definition of RSV-LRTD and SpO2 \<93%, or lower chest wall in-drawing. RSV Very Severe LRTD: Meeting the definition of RSV-LRTD and SpO2 \<90%, or failure to respond/unconscious. RSV Hospitalization: Confirmed RSV and hospitalized for acute medical condition.
Day 1 through end of Part B (Month 6)
Secondary Outcomes (13)
Part A (Cohort 1): Geometric Mean Titer (GMT) of Serum RSV Neutralizing Antibody
Day 1, Day 29, and Month 6
Part A (Cohort 1): Geometric Mean Concentration (GMC) of Serum RSV Prefusion F (Pre-F) Binding Antibody
Day 1, Day 29, and Month 6
Part A (Cohort 1): Geometric Mean Fold Rise (GMFR) of Post-baseline/Baseline Neutralizing Antibody Titers
Day 29 and Month 6
Part A (Cohort 1): GMFR of Post-baseline/Baseline Binding Antibody Concentrations
Day 29 and Month 6
Part A (Cohort 1): Percentage of Participants With Seroresponse in RSV Neutralizing Antibody
Baseline to Day 29 and Month 6
- +8 more secondary outcomes
Study Arms (2)
Part A and Part B: Cohort 1 (2 to <5 Years of Age)
EXPERIMENTALPart A: Participants 2 to \<5 years of age will receive either a single intramuscular (IM) injection of mRNA-1345 or placebo on Day 1. Part B: Participants will have the option to be re-enrolled into a 6-month safety-follow up period.
Part A: Cohort 2 (5 to <18 Years of Age)
EXPERIMENTALParticipants 5 to \<18 years of age will receive a single IM injection of mRNA-1345 on Day 1.
Interventions
Eligibility Criteria
You may qualify if:
- Part A Cohort 1:
- to \<5 years of age at Day 1.
- Healthy, or with stable chronic conditions increasing the risk of RSV disease, per the clinical judgment of the Investigator.
- Cohort 2:
- to \<18 years of age at Day 1.
- Participants with stable chronic conditions increasing the risk of RSV disease.
- Female participants of child-bearing potential may be enrolled in the study, if the participant: 1) has a negative urine pregnancy test at Screening and on the day of injection (Day 1); 2) has practiced adequate contraception or has abstained from all activities that could lead to pregnancy for 28 days prior to Day 1; 3) has agreed to continue adequate contraception through 90 days following injection; and 4) is not currently breastfeeding.
- Part B: Cohort 1 Re-enrollment
- Participants are eligible to be included in the study only if all of the following criteria apply:
- Enrolled and dosed in Part A of Cohort 1; either reached EoS for Part A or were dosed and subsequently discontinued from study for various reasons. This includes participants who were lost to follow-up, if they can be re-engaged.
- Participant's parent(s)/LAR(s) has provided written informed consent for participation in this study.
You may not qualify if:
- Acutely ill or febrile (temperature ≥38.0°Celsius \[100.4°Fahrenheit\]) within 72 hours prior to or at the Screening Visit or Day 1.
- History of a diagnosis or condition that, in the judgment of the Investigator, may affect study assessment or compromise participant safety.
- Has received or plans to receive any licensed or authorized vaccine ≤14 days prior to the study vaccine injection (Day 1) or plans to receive a licensed or authorized vaccine within 14 days after the study vaccine injection.
- Receipt of any prior systemic immunosuppressants. Short courses (\<7 days) of oral corticosteroids are allowed if completed at least 3 months prior to enrollment.
- Receipt of RSV monoclonal antibodies within 6 months prior to enrollment in the study.
- Participated in an interventional clinical study within 28 days (6 months for a study assessing a product unlicensed/unauthorized in this age group in country of residence at time of enrollment) prior to the day of enrollment or plans to do so while enrolled in this study.
- Part B: Cohort 1 Re-enrollment
- \. Participant is currently enrolled in another interventional clinical study.
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- ModernaTX, Inc.lead
Study Sites (50)
Velocity Clinical Research, Phoenix
Phoenix, Arizona, 85006, United States
Headlands Research - Scottsdale
Scottsdale, Arizona, 85260, United States
Velocity Clinical Research - Banning
Banning, California, 92220, United States
ASCADA Research, LLC - Family Medicine
Fullerton, California, 92835, United States
Ark Clinical Research
Long Beach, California, 90815, United States
Peninsula Research Associates (PRA)
Rolling Hills Estates, California, 90274, United States
D&H Doral Research Center, LLC
Doral, Florida, 33122, United States
Kissimmee Clinical Research
Kissimmee, Florida, 34741, United States
Accel Clinical
Largo, Florida, 33777, United States
Med-Care Research
Miami, Florida, 33125, United States
Accel Research Sites - Nona Pediatric Center
Orlando, Florida, 32829, United States
SEC Clinical Research
Pensacola, Florida, 32501, United States
D&H Tamarac Research Center
Tamarac, Florida, 33321, United States
Javara, Inc.
Fayetteville, Georgia, 30214, United States
Velocity Clinical Research-Primary Pediatrics, Macon
Macon, Georgia, 31210, United States
CenExel iResearch, LLC
Savannah, Georgia, 31405, United States
Clinical Research Prime
Idaho Falls, Idaho, 83404, United States
Velocity Clinical Research - Boise
Meridian, Idaho, 83642, United States
Alliance for Multispeciality Research, LLC
El Dorado, Kansas, 67042, United States
Velocity Clinical Research-Kansas City
Overland Park, Kansas, 66210, United States
Velocity Clinical Research - Lafayette
Lafayette, Louisiana, 70508, United States
Velocity Clinical Research Metairie
Metairie, Louisiana, 70006, United States
Great Lakes Research Institute
Southfield, Michigan, 48075, United States
Pediatric & Adolescent Center
Southgate, Michigan, 48195-1896, United States
Clinical Research Institute
Minneapolis, Minnesota, 55402, United States
Velocity Clinical Research, Gulfport
Gulfport, Mississippi, 39503, United States
Velocity Clinical Research- Albuquerque
Albuquerque, New Mexico, 87107, United States
Velocity Clinical Research-Binghamton
Binghamton, New York, 13905, United States
University of Rochester Medical Center (URMC) - Golisano Children's Hospital (GCH)
Rochester, New York, 14620, United States
Senders Pediatrics
South Euclid, Ohio, 44121, United States
The Children's Hospital of Philadelphia - Pediatrics
Philadelphia, Pennsylvania, 19104-4318, United States
DM Clinical Research - Philadelphia
Philadelphia, Pennsylvania, 19107, United States
Velocity Clinical Research - Providence
Providence, Rhode Island, 02886, United States
Coastal Pediatric Research
Charleston, South Carolina, 29414, United States
Tribe Clinical Research
Simpsonville, South Carolina, 29680, United States
Elligo Clinical Research Center
Austin, Texas, 78704, United States
REX Clinical Trials, LLC
Beaumont, Texas, 77701, United States
Javara Inc (Conroe)
Conroe, Texas, 77384, United States
West Houston Clinical Research Service
Houston, Texas, 77055, United States
DM Clinical Research - CyFair
Houston, Texas, 77065, United States
Village Pediatrics
Plano, Texas, 75024, United States
Javara Inc/Texas Health Care, PLLC d/b/a/ Privia Medical Group-North Texas
Stephenville, Texas, 76401, United States
Victoria Clinical Research Group
Victoria, Texas, 77901, United States
Velocity Clinical Research - Salt Lake City
West Jordan, Utah, 84088, United States
PI-Coor Clinical Research, LLC
Annandale, Virginia, 22003, United States
Clinical Research Partners
Richmond, Virginia, 23226, United States
National Clinical Research, Inc.
Richmond, Virginia, 23294, United States
CEVAXIN Chorrera
La Chorrera, 07066, Panama
CEVAXIN Avenida Mexico
Panama City, 07093, Panama
CEVAXIN 24 de Diciembre
Panama City, 07114, Panama
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Results Point of Contact
- Title
- Moderna WeCare Team
- Organization
- ModernaTX, Inc.
Publication Agreements
- PI is Sponsor Employee
- No
- Restrictive Agreement
- Yes
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
October 18, 2023
First Posted
October 24, 2023
Study Start
October 24, 2023
Primary Completion
June 27, 2025
Study Completion
June 27, 2025
Last Updated
August 18, 2026
Results First Posted
August 18, 2026
Record last verified: 2026-07