A Study to Evaluate the Safety and Immunogenicity of the mRNA COVID-19 Vaccines in Healthy Children Between 6 Months to Less Than 6 Years of Age

NCT ID: NCT05436834

Last Updated: 2025-11-26

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE3
• Total Enrollment: 1807 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-06-21
• Study Completion Date: 2025-10-20

Brief Summary

This study will evaluate the safety and immunogenicity of the mRNA-1273.214 vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concerns (VOCs) in participants aged 6 months to <6 years, when administered as a primary series in SARS-CoV-2 vaccine-naïve participants (Part 1) and a single booster dose (BD) given to participants who previously received 2 doses of the mRNA-1273 vaccine as a primary series (Part 2); and will evaluate the safety and immunogenicity of the mRNA-1273.815 vaccine, when administered as a BD in participants aged 6 months to <6 years (Part 3) and when administered to SARS-CoV-2 vaccine-naïve participants aged 2 years to <5 years of age (Part 4).

Detailed Description

Part 1 will enroll participants aged 6 months to <6 years who have not been previously vaccinated against SARS-CoV-2. Participants will receive 2 doses of the mRNA-1273.214 vaccine.

Part 2 will enroll participants aged 6 months to <6 years who have previously been vaccinated with a mRNA-1273 primary series in Study mRNA-1273-P204 (NCT04796896). Participants will receive a single BD of the mRNA-1273.214 vaccine, at least 4 months after completion of the mRNA-1273 primary series.

Part 3 will enroll participants aged 6 months to <6 years who have previously been vaccinated with an authorized/approved COVID-19 vaccine. Participants will receive a BD of the mRNA-1273.815 vaccine at least 4 months after the last receipt of a COVID-19 vaccine.

Part 4 will evaluate mRNA-1273.815 vaccine administered as a single dose to SARS-CoV-2 vaccine-naïve participants aged 2 years to <5 years of age enrolled in Cohort A (Part 4A), compared to 2 doses given to SARS-CoV-2 vaccine-naïve participants aged 6 months to <2 years enrolled in Cohort B (Part 4B).

Conditions

SARS-CoV-2

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: SEQUENTIAL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: NONE

Study Groups

mRNA-1273.214 (Part 1)

Participants who have not been previously vaccinated against SARS-CoV-2, will receive 2 intramuscular (IM) injections of mRNA-1273.214 vaccine on Day 1 and Day 29.

Group Type: EXPERIMENTAL

mRNA-1273.214

Intervention Type: BIOLOGICAL

Sterile liquid for injection

mRNA-1273.214 (Part 2)

Participants who have previously been vaccinated with a mRNA-1273 primary series, will receive a single IM BD of mRNA-1273.214 vaccine at least 4 months after completion of the mRNA-1273 primary series.

Group Type: EXPERIMENTAL

mRNA-1273.214

Intervention Type: BIOLOGICAL

Sterile liquid for injection

mRNA-1273.815 (Part 3)

Participants who have previously been vaccinated with an authorized/approved COVID-19 vaccine, will receive a single IM BD of mRNA-1273.815 vaccine on BD Day 1, at least 4 months after the last dose of a COVID-19 vaccine.

Group Type: EXPERIMENTAL

mRNA-1273.815

Intervention Type: BIOLOGICAL

Sterile liquid for injection

mRNA-1273.815 (Part 4)

Participants in Part 4 Cohort A will receive a single IM injection of mRNA-1273.815 vaccine on Day 1. Participants in Part 4 Cohort B will receive IM injections of mRNA-1273.815 vaccine on Day 1 and Day 29.

Group Type: EXPERIMENTAL

mRNA-1273.815

Intervention Type: BIOLOGICAL

Sterile liquid for injection

Interventions

mRNA-1273.214

Sterile liquid for injection

Intervention Type: BIOLOGICAL

mRNA-1273.815

Sterile liquid for injection

Intervention Type: BIOLOGICAL

Eligibility Criteria

Inclusion Criteria

• The participant is 6 months to <6 years for Parts 1, 2, and 3; 2 years to <5 years for Part 4A; and 6 months to <2 years for Part 4B at the time of consent (Screening Visit). Note: for Part 1, participant must be at least 6 months old and must not have reached 6 years of age at the time of administration of first dose. For Part 4B, the participant must be at least 6 months old and must not have reached 2 years of age at the time of administration of first dose.
• If the participant has a chronic disease (that is, asthma, diabetes mellitus, cystic fibrosis, human immunodeficiency virus [HIV] infection), the disease should be stable, per investigator assessment, so that the participant can be considered eligible for inclusion. Stable diseases are those which have had no change in their status or in the medications required to control them in the 6 months prior to Screening Visit. Note: a change in medication for dose optimization (that is, insulin dose changes, adjustments for age-related weight gain), change within class of medication, or reduction in dose are not considered signs of instability.
• In the investigator's opinion, the parent(s)/legally authorized representative(s) (LAR[s]) understand and are willing and physically able to comply with protocol-mandated follow-up, including all procedures and provide written informed consent.
• The participant is 2 years or older and has a body mass index (BMI) at or above the second percentile according to World Health Organization (WHO) Child Growth Standards at the Screening Visit.

OR

• The participant is less than 2 years of age and the participant's height and weight are both at or above the second percentile according to WHO Child Growth Standards at the Screening Visit.

• The participant was born at full-term (≥ 37 weeks gestation) with a minimum birth weight of 2.5 kilograms (kg).

• The participant must have received 2 doses of mRNA-1273, approximately 28 to 35 days apart, as 25-μg primary series, and second dose was given at least 4 months prior to enrollment.

• The participant must have received an age-appropriate immunization series of an authorized/approved COVID-19 vaccine, with the last dose given at least 4 months prior to enrolment (Previous vaccines NOT allowed are: XBB.1.5-containing formulation).

Exclusion Criteria

• Has a known history of SARS-CoV-2 infection (that is, reported AE of COVID-19 or asymptomatic SARS-CoV-2 infection during Study mRNA-1273-P204 at the time of rollover into mRNA-1273-P306 or during Part 1 at the time of rollover into Part 3) in the 90 days prior to dosing in this study.
• Is acutely ill or febrile 24 hours prior to or at the Screening Visit. Fever is defined as a body temperature ≥ 38.0°Celsius (C)/≥ 100.4°Fahrenheit (F). Participants who meet this criterion may have visits rescheduled within the relevant study visit windows. Afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.
• For Parts 1 and 4, participant has previously been administered an investigational or approved CoV (that is, SARS-CoV-2, SARS-CoV, Middle East respiratory syndrome coronavirus [MERS-CoV]) vaccine. For Part 2, participant who received any approved/investigational CoV vaccine are ineligible to participate except for those who received mRNA-1273 (prototype) vaccine.
• Has undergone treatment with investigational or approved agents for prophylaxis against COVID-19 (including receipt of SARS-CoV-2 monoclonal antibodies for prophylaxis or treatment) within 90 days prior to enrollment.
• Has a known hypersensitivity to a component of the vaccine or its excipients. Hypersensitivity includes, but is not limited to, anaphylaxis or immediate allergic reaction of any severity to a previous dose of an mRNA COVID-19 vaccine or any of its components (including polyethylene glycol [PEG] or immediate allergic reaction of any severity to polysorbate).
• Has a medical or psychiatric condition that, according to the investigator's judgment, may pose additional risk as a result of participation, interfere with safety assessments, or interfere with interpretation of results.
• Has a history of diagnosis or condition that, in the judgment of the investigator, may affect study endpoint assessment or compromise participant safety, specifically the following:

• Congenital or acquired immunodeficiency, other than well-controlled HIV infection.
• Chronic hepatitis or suspected active hepatitis
• A bleeding disorder that is considered a contraindication to IM injection or phlebotomy
• Dermatologic conditions that could affect local solicited AR assessments
• Any prior diagnosis of malignancy (excluding nonmelanoma skin cancer)
• Has received the following:

• Any routine vaccination with inactivated or live vaccine(s) within 14 days prior to study vaccination or plans to receive such a vaccine through 14 days following study vaccination.

Note: This excludes influenza vaccine that may be given anytime, but ideally at least 7 days before study dose. If a participant receives an influenza vaccine, this should be captured within the concomitant medication electronic case report form (eCRF).

• Systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to the day of enrollment (for corticosteroids, ≥1 milligrams (mg)/kg/day or ≥ 10 mg/day prednisone equivalent, if participant weighs >10 kg). Participants may have visits rescheduled for enrollment if they no longer meet this criterion within the Screening Visit window. Inhaled, nasal, and topical steroids, and palivizumab are allowed.
• Intravenous (IV) or subcutaneous (SC) blood products (red cells, platelets, immunoglobulins) within 3 months prior to enrollment.

• Minimum Eligible Age: 6 Months
• Maximum Eligible Age: 5 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

ModernaTX, Inc.

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

AES- AS- Solano & Terront Servicios Médicos LTDA (UNIENDO) Bogotá

Bogotá, Bogota D.C., Colombia

Trinity Clinical Research, LLC

Bessemer, Alabama, United States

Velcocity Clinical Research

Banning, California, United States

Sera Collection Research Services

Montebello, California, United States

Center For Clinical Trials LLC -Paramount

Paramount, California, United States

University of Colorado

Aurora, Colorado, United States

Meridian Clinical Research

Washington D.C., District of Columbia, United States

Prohealth Research Center

Doral, Florida, United States

University of Florida Jacksonville

Jacksonville, Florida, United States

Kissimmee Clinical Research

Kissimmee, Florida, United States

Med-Care Research

Miami, Florida, United States

University of South Florida

Tampa, Florida, United States

IResearch

Decatur, Georgia, United States

Meridian Clinical Research

Macon, Georgia, United States

Velcocity Clinical Research

Meridian, Idaho, United States

Lurie Childrens Hospital

Chicago, Illinois, United States

Meridian Clinical Research

Overland Park, Kansas, United States

Michael W. Simon MD, PSC

Lexington, Kentucky, United States

University of Kentucky

Lexington, Kentucky, United States

Velocity Clinical Research - Lafayette - PPDS

Lafayette, Louisiana, United States

MedPharmics

Metairie, Louisiana, United States

Velocity Clinical Research - Covington - PPDS

Metairie, Louisiana, United States

Clinical Research Institute

Minneapolis, Minnesota, United States

University of Missouri Health Care

Columbia, Missouri, United States

Meridian Clinical Research

Hastings, Nebraska, United States

Meridian Clinical Research

Lincoln, Nebraska, United States

Be Well Clinical Studies, LLC - Lincoln - ERN - PPDS

Lincoln, Nebraska, United States

Quality Clinical Research

Omaha, Nebraska, United States

Velocity Clinical Research

Albuquerque, New Mexico, United States

Meridian Clinical Research

Binghamton, New York, United States

WellNow Urgent Care Clinical Research

East Amherst, New York, United States

Child Healthcare Associates - East Syracuse

East Syracuse, New York, United States

Lynn Health Science Institute

Oklahoma City, Oklahoma, United States

Velcocity Clinical Research

East Greenwich, Rhode Island, United States

Coastal Pediatric Associates

Charleston, South Carolina, United States

Meridian Clinical Research

Charleston, South Carolina, United States

MUSC

Charleston, South Carolina, United States

Le Bonheur Childrens Hospital

Memphis, Tennessee, United States

Velocity Clinical Research Austin

Austin, Texas, United States

REX Clinical Trials, LLC Beaumont

Beaumont, Texas, United States

Velcocity Clinical Research

Cedar Park, Texas, United States

BRCR Global Texas

Edinburg, Texas, United States

Village Health Partners - Frisco Medical Village

Frisco, Texas, United States

Ventavia Research Group

Houston, Texas, United States

Cyfair Clinical Reseach Center

Houston, Texas, United States

Texas Center for Drug Development

Houston, Texas, United States

Victoria Clinical Research Group

Victoria, Texas, United States

PI Coor Clinical Research LLC

Burke, Virginia, United States

Clinical Research Partners

Richmond, Virginia, United States

AES - AS - Glenny Corp. S.A. Buenos Aires

CABA, Buenos Aires F.D., Argentina

Hospital Militar Central Cirujano Mayor Dr. Cosme Argerich

Buenos Aires, Ciudad Autónoma de BuenosAires, Argentina

AES - AS - Clinica Mayo de Urgencias

San Miguel de Tucumán, Tucumán Province, Argentina

Consultorios Médicos Dr. Doreski - PPDS

Buenos Aires, , Argentina

Centro de Estudios Clinicos e Investigaciones Medicas (CECIM)

Santiago, Santiago Metropolitan, Chile

AES - AS - Centro de Investigación Clínica CIC S.A.S (CECIC) Medellín

Medellín, Antioquia, Colombia

Clínica de Costa S.A.S

Barranquilla, Atlántico, Colombia

Centro de Atencion e Investigacion Medica S.A.S. - CAIMED Aguazul

Aguazul, Casanare Department, Colombia

Centro de Atencion e Investigacion Medica S.A - Yopal - CAIMED

Yopal, Casanare Department, Colombia

Policlínico Social del Norte

Bogotá, Cundinamarca, Colombia

Clínica de la Costa S.A.S- Sede Cartagena

Cartagena, Departamento de Bolívar, Colombia

Centro de Atención e Investigación Médica S.A.S.- CAIMED - S.A.S. Sede Acacias

Acacías, Meta Department, Colombia

Caimed Dominicana S.A.S - CAIMED - PPDS

Santo Domingo, Distrito NacionalSanto Domingo, Dominican Republic

Registrum- La Altagracia

Salvaleón de Higüey, La Altagracia Province, Dominican Republic

Hospital Materno Infantil San Lorenzo de Los Mina

Santo Domingo Este, Santo Domingo Province, Dominican Republic

Hospital General Regional Dr. Marcelino Velez Santana

Santo Domingo Iesta, Santo Domingo Province, Dominican Republic

Unidad de Vacunas e Investigación Instituto Dermatologico Dominicano y Cirugía de Piel Dr. Huberto B

Santo Domingo, , Dominican Republic

CAENSA Clinical Trial

Panama City, , Panama

Centro De Vacunacion Internacional, S.A. - David - Cevaxin - PPDS

Panama City, , Panama

CEVAXIN 24 de diciembre - PPDS

Panama City, , Panama

CEVAXIN Avenida México - PPDS

Panama City, , Panama

CEVAXIN Chorrera - PPDS

Panama City, , Panama

Curaex Clinical Trial

Panama City, , Panama

Instituto de Investigaciones Científicas y Servicios de Alta Tecnología Asociación de Interés Panama

Panama City, , Panama

Caribbean Medical Research Center

San Juan, , Puerto Rico

Countries

United States; Argentina; Chile; Colombia; Dominican Republic; Panama; Puerto Rico

References

Dixit A, Bennett R, Ali K, Griffin C, Clifford RA, Turner M, Poston R, Hautzinger K, Yeakey A, Girard B, Zhou W, Deng W, Zhou H, Schnyder Ghamloush S, Kuter BJ, Slobod K, Miller JM, Priddy F, Das R; ROVER Study Investigators. Interim safety and immunogenicity of COVID-19 omicron BA.1 variant-containing vaccine in children in the USA: an open-label non-randomised phase 3 trial. Lancet Infect Dis. 2024 Jul;24(7):687-697. doi: 10.1016/S1473-3099(24)00101-4. Epub 2024 Mar 19.

Reference Type: DERIVED

PMID: 38518789 (View on PubMed)

Other Identifiers

mRNA-1273-P306

Identifier Type: -

Identifier Source: org_study_id