A Study to Evaluate the Safety, Reactogenicity, and Immunogenicity of mRNA-1283 in Participants ≥6 Months to <12 Years of Age
A Phase 2, Randomized, Observer-Blind, Dose Ranging Study to Evaluate the Safety, Reactogenicity, and Immunogenicity of mRNA-1283 in Participants ≥6 Months to <12 Years of Age
1 other identifier
interventional
300
6 countries
31
Brief Summary
This study will evaluate 2 dose levels of mRNA-1283 in participants ≥6 months to \<12 years to determine the optimal dose level per age group.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for phase_2
Started Sep 2026
Typical duration for phase_2
31 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
Study Start
First participant enrolled
September 1, 2026
CompletedFirst Submitted
Initial submission to the registry
September 2, 2026
CompletedFirst Posted
Study publicly available on registry
September 9, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
August 30, 2029
ExpectedStudy Completion
Last participant's last visit for all outcomes
August 30, 2029
September 9, 2026
September 1, 2026
3 years
September 2, 2026
September 2, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (6)
Cohort 1 and Cohort 2: Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs)
Day 1 through Day 7; 7 Days following injection
Cohort 1 and Cohort 2: Number of Participants with Unsolicited Adverse Events (AEs)
Day 1 through Day 28 (Cohort 1); 28 Days following injection (Cohort 2)
Cohort 1 and Cohort 2: Number of Participants with Any Medically Attended AEs (MAAEs), Serious AEs (SAEs), AEs of Special Interest (AESIs), and AEs Leading to Discontinuation from the Study
Day 1 through End of Study (Month 13)
Cohort 1 and Cohort 2: Geometric Mean Value of Antibody Level Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Target Variant
Day 29 VISIT (Cohort 1), Day 57 VISIT (Cohort 2)
Cohort 1 and Cohort 2: Geometric Mean Fold Rise of Antibody Level Against SARS-CoV-2
Day 29 (Cohort 1), Day 57 (Cohort 2)
Cohort 1 and Cohort 2: Number of Participants with Seroresponse Rate
Day 29 (Cohort 1), Day 57 (Cohort 2)
Study Arms (6)
Cohort 1: mRNA-1283 Dose Level 1
EXPERIMENTALParticipants aged 2 to \<12 years receive one IM dose of on Day 1.
Cohort 1: mRNA-1283 Dose Level 2
EXPERIMENTALParticipants aged 2 to \<12 years receive one IM dose of on Day 1.
Cohort 1: mRNA-1273
ACTIVE COMPARATORParticipants aged 2 to \<12 years receive one IM dose of on Day 1.
Cohort 2: mRNA-1283 Dose Level 1
EXPERIMENTALParticipants aged 6 months to \<2 years receive two IM doses 28 days apart (Days 1 and 29).
Cohort 2: mRNA-1283 Dose Level 2
EXPERIMENTALParticipants aged 6 months to \<2 years receive two IM doses of 28 days apart (Days 1 and 29).
Cohort 2: mRNA-1273
ACTIVE COMPARATORParticipants aged 6 months to \<2 years receive two IM doses 28 days apart (Day 1 and 29).
Interventions
Eligibility Criteria
You may qualify if:
- Participant is male or female, between ≥2 years to \<12 years of age for Cohort 1 or ≥6 months to \<2 years of age for Cohort 2 (calculated from date of birth) at the time of signing the informed consent/assent.
- Participant is in good general health as determined by medical evaluation including medical history and physical examination. Participants with chronic but stable conditions (eg, gastroesophageal reflux disease, asthma) may be eligible to enroll, provided the condition is well-controlled and not expected to interfere with study participation or outcomes.
- For participants in Cohort 2: the participant was born at ≥37 weeks, with a minimum birth weight of 2.5 kilograms, without fetal growth restriction.
- Female participants who have reached menarche may be enrolled in the study if all of the following criteria are fulfilled:
- Has a negative highly sensitive pregnancy test (urine or serum) as required by local regulations within 24 hours before the study intervention.
- Is not currently chest/breastfeeding.
- Has been using a highly effective contraceptive method or has abstained from all activities that could lead to pregnancy for at least 28 days prior to the study injection (Day 1). The investigator should evaluate the potential for contraceptive method failure (for example, noncompliance, recently initiated) in relationship to the study injection.
- Has agreed to continue adequate contraception through the end of study. Contraceptive use by participants should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.
You may not qualify if:
- History of SARS-CoV-2 infection within 3 months prior to enrollment.
- Acutely ill or febrile (temperature ≥38.0℃elsius \[100.4°Fahrenheit\]) within 72 hours prior to or at the screening visit or Day 1. Participants who are acutely ill or febrile may be scheduled for a separate dosing visit within the protocol-specified window for screening and will retain their initially assigned participant number. Afebrile participants with minor illnesses can be enrolled at the discretion of the Investigator.
- Any medical, psychiatric, or occupational condition, including reported history of drug, or alcohol abuse in the parent(s)/ legally authorized representative(s), that, in the opinion of the investigator, might pose additional risk due to child's participation in the study, could interfere with safety assessments, or could interfere with the interpretation of study results.
- Receipt of the 2026-2027 formulation of a COVID-19 vaccine at any time prior to enrollment.
- Receipt of any COVID-19 vaccine within 6 months prior to enrollment.
- Receipt of any nonstudy vaccination within 14 days (28 days for live vaccines) prior to study intervention or plans to receive a nonstudy vaccine through 14 days after administration of study intervention.
- Received systemic immunosuppressive treatment, including long-acting biological therapies that affect immune responses (for example, infliximab), within 180 days prior to Day 1 (baseline) or plans to do so during the study.
- Received systemic immunoglobulins or blood products within 90 days prior to the screening visit or plans to receive them during the study. Exception: Nirsevimab and clesrovimab are allowed.
- For infants who receive breast milk, maternal receipt of systemic immunosuppressive therapy during lactation. This includes ≥10 milligrams/day of prednisone or equivalent for 14 days or more, or other immunomodulating agents (for example, biologics, calcineurin inhibitors, disease-modifying agents) that may be transferred via breastmilk and impact infant immune development or vaccine response.
- Has participated in an interventional clinical study within 28 days prior to the screening visit based on the medical history interview or plans to do so while participating in this study.
- Has been placed under the control or protection of an agency, organization, institution, or entity by the courts, the government, or a government body, acting in accordance with powers conferred on them by laws, and regulation. Does not include a child who is adopted or has an appointed legal guardian.
- Receipt of any nonstudy vaccination within 14 days (28 days for live vaccines) prior to study intervention or plans to receive a nonstudy vaccine through 14 days after administration of study intervention.
- History of any myocarditis, pericarditis, or myopericarditis
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- ModernaTX, Inc.lead
Study Sites (31)
Orange County Research Center
Ontario, California, 91762, United States
Hope Research Network
Miami, Florida, 33166, United States
Spotlight Research Center - Internal Medicine
Miami, Florida, 33167, United States
Indago Research and Health Cen
Miami Lakes, Florida, 33016, United States
MplusM - D&H Tamarac Research Center
Tamarac, Florida, 33321, United States
Eagle Clinical Research, LLC
Chicago, Illinois, 60621, United States
Great Lakes Research Institute -Southfield
Southfield, Michigan, 48075, United States
Senders Pediatrics
South Euclid, Ohio, 44121, United States
REX Clinical Trials
Beaumont, Texas, 77701, United States
PanAmerican Clinical Research, LLC.
Brownsville, Texas, 78520, United States
South Ogden Family Medicine
South Ogden, Utah, 84403, United States
Clinical Research Partners
Richmond, Virginia, 23226, United States
Childrens Hospital Regional Medical Center
Seattle, Washington, 98105, United States
Fundacion Respirar - Consultorios Medicos Dra De Salvo
Ciudad Autonoma, Buenos Aires, Argentina
Instituto Medico de la Fundacion Estudios Clinicos
Casilda, Santa Fe Province, Argentina
Hospital del Nino Jesus
San Miguel de Tucumán, Tucumán Province, Argentina
Medvacplus Srl Fundacion Clinica Cruz Jiminian
Cristo Rey, Distrito Nacional (Santo Domingo), 10501, Dominican Republic
Instituto Dermatologico y Cirugia de Piel ''Dr. Huberto Bogaert Diaz'' (IDCP-DHBD)
Santo Domingo, Distrito Nacional (Santo Domingo), 10306, Dominican Republic
Hospital General y de Especialidades Nuestra Señora de la Altagracia
Salvaleón de Higüey, La Altagracia Province, Dominican Republic
Hospital Materno Infantil San Lorenzo De Los Mina
Santo Domingo, Nacional, 11901, Dominican Republic
Centro de Investigacion Clínica y Medicina Traslacional (CIMeT)
Guadalajara, Jalisco, Mexico
Hospital Infantil de México Federico Gómez - Pediatric Gastroenterology
Mexico City, Mexico City, Mexico
Instituto Nacional de Pediatria
Mexico City, Mexico City, Mexico
PanAmerican Clinical Research - Queretaro
Querétaro City, Querétaro, Mexico
Centro de Salud Tizimin
Tizimín, Yucatán, Mexico
CEVAXIN Avenida Mexico
Calidonia, Provincia de Panamá, 7094, Panama
CEVAXIN Chorrera
La Chorrera, Provincia de Panamá, Panama
CEVAXIN 24 de Diciembre
Panama City, Provincia de Panamá, Panama
Instituto de Investigaciones Cienti-ficas Y Servicios de Alta Tecnologia Asociacion de Interes Panama; . Centro de Investigación, Innovación y Gestión del Conocimiento de Ciudad de la Salud, Caja de Seguro social
Panama City, Provincia de Panamá, Panama
Ponce Health Sciences University
Ponce, Puerto Rico, Puerto Rico
BRCR Global
San Juan, Puerto Rico, 00907, Puerto Rico
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 2
- Allocation
- RANDOMIZED
- Masking
- QUADRUPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
- Masking Details
- The study is observer-blind where only delegated unblinded study personnel will have access to study intervention assignments.
- Purpose
- PREVENTION
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
September 2, 2026
First Posted
September 9, 2026
Study Start
September 1, 2026
Primary Completion (Estimated)
August 30, 2029
Study Completion (Estimated)
August 30, 2029
Last Updated
September 9, 2026
Record last verified: 2026-09