SARS-CoV-2Phase 3NCT05436834
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
A Phase 3 study testing mRNA-1273.214 and mRNA-1273.815 in people with SARS-CoV-2, run by ModernaTX, Inc. at 74 sites in 7 countries.
Trial 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… Read more about this study
- Who is it for?
- Ages 6 months to 5 yearsHealthy volunteers can take part
- Conditions the study is for
- SARS-CoV-2
- What is being tested?
- mRNA-1273.214 and mRNA-1273.815
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 1,807 participants
- Where
- 74 sitesin 7 countries
- Study dates
- 21 Jun 2022to 20 Oct 2025
- Phase
- Phase 3
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 6 months to 5 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- 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.
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- Special inclusion criteria for participants aged 6 months to < 12 months:
- 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).
Who cannot join
- 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.
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- 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.
- Note: Other inclusion and exclusion criteria may apply.
Trial locations and contacts
74 sites in 7 countries.
74 sites in 7 countries
United States48 sites
Velocity Clinical Research
Albuquerque, New Mexico, 87102
University of Colorado
Aurora, Colorado, 80045
Velocity Clinical Research Austin
Austin, Texas, 78759
Velcocity Clinical Research
Banning, California, 92220
REX Clinical Trials, LLC Beaumont
Beaumont, Texas, 77701-3739
Trinity Clinical Research, LLC
Bessemer, Alabama, 34020
Meridian Clinical Research
Binghamton, New York, 13901
PI Coor Clinical Research LLC
Burke, Virginia, 22015
Velcocity Clinical Research
Cedar Park, Texas, 78613
Coastal Pediatric Associates
Charleston, South Carolina, 29414
Meridian Clinical Research
Charleston, South Carolina, 29414
MUSC
Charleston, South Carolina, 29425
Lurie Childrens Hospital
Chicago, Illinois, 60611
University of Missouri Health Care
Columbia, Missouri, 65212
IResearch
Decatur, Georgia, 30030
Prohealth Research Center
Doral, Florida, 33166
WellNow Urgent Care Clinical Research
East Amherst, New York, 14051
Velcocity Clinical Research
East Greenwich, Rhode Island, 02818
Child Healthcare Associates - East Syracuse
East Syracuse, New York, 13057
BRCR Global Texas
Edinburg, Texas, 78539
Village Health Partners - Frisco Medical Village
Frisco, Texas, 75033
Meridian Clinical Research
Hastings, Nebraska, 68901
Ventavia Research Group
Houston, Texas, 77008
Cyfair Clinical Reseach Center
Houston, Texas, 77065
Texas Center for Drug Development
Houston, Texas, 77081
University of Florida Jacksonville
Jacksonville, Florida, 32209
Kissimmee Clinical Research
Kissimmee, Florida, 34741
Velocity Clinical Research - Lafayette - PPDS
Lafayette, Louisiana, 70508
Michael W. Simon MD, PSC
Lexington, Kentucky, 40517
University of Kentucky
Lexington, Kentucky, 40536
Meridian Clinical Research
Lincoln, Nebraska, 68510
Be Well Clinical Studies, LLC - Lincoln - ERN - PPDS
Lincoln, Nebraska, 68516
Meridian Clinical Research
Macon, Georgia, 31210
Le Bonheur Childrens Hospital
Memphis, Tennessee, 38105
Velcocity Clinical Research
Meridian, Idaho, 83642
MedPharmics
Metairie, Louisiana, 70006
Velocity Clinical Research - Covington - PPDS
Metairie, Louisiana, 70006
Med-Care Research
Miami, Florida, 33125
Clinical Research Institute
Minneapolis, Minnesota, 55402
Sera Collection Research Services
Montebello, California, 90640
Lynn Health Science Institute
Oklahoma City, Oklahoma, 73112
Quality Clinical Research
Omaha, Nebraska, 68114
Meridian Clinical Research
Overland Park, Kansas, 66210
Center For Clinical Trials LLC -Paramount
Paramount, California, 90723
Clinical Research Partners
Richmond, Virginia, 23226
University of South Florida
Tampa, Florida, 33612
Victoria Clinical Research Group
Victoria, Texas, 77901
Meridian Clinical Research
Washington D.C., District of Columbia, 20016
Colombia8 sites
Centro de Atención e Investigación Médica S.A.S.- CAIMED - S.A.S. Sede Acacias
Acacías, Meta Department, 507001
Centro de Atencion e Investigacion Medica S.A.S. - CAIMED Aguazul
Aguazul, Casanare Department, 856010
Clínica de Costa S.A.S
Barranquilla, Atlántico, 80020
AES- AS- Solano & Terront Servicios Médicos LTDA (UNIENDO) Bogotá
Bogotá, Bogota D.C., 110221
Policlínico Social del Norte
Bogotá, Cundinamarca, 110131
Clínica de la Costa S.A.S- Sede Cartagena
Cartagena, Departamento de Bolívar, 130011
AES - AS - Centro de Investigación Clínica CIC S.A.S (CECIC) Medellín
Medellín, Antioquia, 050021
Centro de Atencion e Investigacion Medica S.A - Yopal - CAIMED
Yopal, Casanare Department, 850001
Panama7 sites
CAENSA Clinical Trial
Panama City
Centro De Vacunacion Internacional, S.A. - David - Cevaxin - PPDS
Panama City
CEVAXIN 24 de diciembre - PPDS
Panama City
CEVAXIN Avenida México - PPDS
Panama City
CEVAXIN Chorrera - PPDS
Panama City
Curaex Clinical Trial
Panama City
Instituto de Investigaciones Científicas y Servicios de Alta Tecnología Asociación de Interés Panama
Panama City
Dominican Republic5 sites
Registrum- La Altagracia
Salvaleón de Higüey, La Altagracia Province, 23000
Caimed Dominicana S.A.S - CAIMED - PPDS
Santo Domingo, Distrito NacionalSanto Domingo, 11903
Unidad de Vacunas e Investigación Instituto Dermatologico Dominicano y Cirugía de Piel Dr. Huberto B
Santo Domingo, 10305
Hospital Materno Infantil San Lorenzo de Los Mina
Santo Domingo Este, Santo Domingo Province, 11901
Hospital General Regional Dr. Marcelino Velez Santana
Santo Domingo Iesta, Santo Domingo Province, 11117
Argentina4 sites
Hospital Militar Central Cirujano Mayor Dr. Cosme Argerich
Buenos Aires, Ciudad Autónoma de BuenosAires, C1426BOS
Consultorios Médicos Dr. Doreski - PPDS
Buenos Aires, C1426ABP
AES - AS - Glenny Corp. S.A. Buenos Aires
CABA, Buenos Aires F.D., C1430CKE
AES - AS - Clinica Mayo de Urgencias
San Miguel de Tucumán, Tucumán Province, T4000CAM
Chile1 site
Centro de Estudios Clinicos e Investigaciones Medicas (CECIM)
Santiago, Santiago Metropolitan, 8320000
About this study
Official title: An Open-Label, Phase 3 Study to Evaluate the Safety and Immunogenicity of mRNA Vaccines for SARS-CoV-2 Variants in Participants Aged 6 Months to < 6 Years
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).
Read the 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
- Being tested
- mRNA-1273.214, mRNA-1273.815
- Keywords
- Coronavirus disease 2019, COVID-19
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
mRNA-1273.214Biological
Sterile liquid for injection
mRNA-1273.815Biological
Sterile liquid for injection
| Study group | Role | What they receive |
|---|---|---|
| mRNA-1273.214 (Part 1) | Experimental | 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. Receives: Biological: mRNA-1273.214 |
| mRNA-1273.214 (Part 2) | Experimental | 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. Receives: Biological: mRNA-1273.214 |
| mRNA-1273.815 (Part 3) | Experimental | 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. Receives: Biological: mRNA-1273.815 |
| mRNA-1273.815 (Part 4) | Experimental | 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. Receives: Biological: mRNA-1273.815 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs)
Measured: Up to Day 8 (7 days post-vaccination)
Number of Participants with Unsolicited Adverse Events (AEs)
Measured: Up to Day 29 (28 days after each injection)
Number of Participants with Medically-Attended AEs (MAAEs)
Measured: Up to Day 394 (12 months after last dose)
Number of Participants with Serious AEs (SAEs)
Measured: Up to Day 394 (12 months after last dose)
Number of Participants with Adverse Events of Special Interest (AESI)
Measured: Up to Day 394 (12 months after last dose)
Number of Participants with AEs Leading to Withdrawal
Measured: Up to Day 394 (12 months after last dose)
Geometric Mean (GM) of the Serum Antibody (Ab) Level against Omicron BA.1 and Ancestral SARS-CoV-2 after mRNA-1273.214 Administration at Day 57
Measured: Day 57
GM of the Serum Ab Level against Omicron BA.1 and Ancestral SARS-CoV-2 after mRNA-1273.214 Administration at Day 29
Measured: Day 29
Seroresponse Rate (SRR) against Omicron BA.1 and Ancestral SARS-CoV-2 after mRNA-1273.214 Administration
Measured: Day 29
GM of the Serum Ab Level against Omicron XBB.1.5 after mRNA-1273.815 Administration
Measured: Up to Day 57
Secondary outcomes (3)
SRR against Omicron BA.1 and Ancestral SARS-CoV-2 after mRNA-1273.214 Administration Regardless of prior SARS-CoV-2 Infection
Measured: Day 57
GM of the Serum Ab Level against Omicron XBB.1.5 after mRNA-1273.815 Administration Regardless of prior SARS-CoV-2 Infection
Measured: Up to Day 57
SRR against Omicron XBB.1.5 after mRNA-1273.815 Administration Regardless of prior SARS-CoV-2 Infection
Measured: Up to Day 57
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jun 2022
- Study start21 Jun 2022
- Primary completion20 Oct 2025
- Study completion20 Oct 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for SARS-CoV-2Studies of the same condition, open and under way.
- More trials run by ModernaTX, Inc.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 1,807 participants (actual)
Sponsor and investigators
- Lead sponsor
- ModernaTX, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05436834
- Sponsor's protocol ID
- mRNA-1273-P306
- Status last verified
- Nov 2025
- First submitted
- 27 Jun 2022
- Last updated
- 26 Nov 2025
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Publications
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.
PubMed 38518789