Phase 3
N=11,942
A Study to Evaluate Safety and Effectiveness of mRNA-1273 COVID-19 Vaccine in Healthy Children Between 6 Months of Age and Less Than 12 Years of Age
SARS-CoV-2
Bottom Line
View on ClinicalTrials.gov: NCT04796896 ↗Enrolled (actual)
11,942
Serious AEs
0.9%
Results posted
Jun 2025
Primary outcome: Primary: Parts 1, 2, and 3: Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs) — 216; 221; 93; 24 Participants
Study Design & Population
- Study type
- Interventional
- Phase
- Phase 3
- Interventions
- mRNA-1273 (Biological); Placebo (Biological); mRNA-1273.214 (Biological)
- Age
- Pediatric · 0+ yrs
- Sex
- All
- Sponsor
- ModernaTX, Inc.
- Primary completion
- Mar 2024
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Parts 1, 2, and 3: Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs) |
216; 221; 93; 24; 46; 7 | — |
| PRIMARY Parts 1, 2, and 3: Number of Participants With Unsolicited AEs |
38; 20; 24; 8; 4; 1 | — |
| PRIMARY Parts 1, 2, and 3: Number of Participants With Serious Adverse Events (SAEs), AEs of Special Interest (AESIs), Medically Attended AEs (MAAEs), and AEs Leading to Discontinuation From Study |
1; 1; 1; 0; 0; 0 | — |
| PRIMARY Parts 1 and 2: Geometric Mean (GM) Value of Serum Pseudovirus Neutralizing Antibody ID50 Titers From Study mRNA-1273-P204 (P204) Vaccine Recipients at Day 57 Compared With Those From Young Adult (18 to 25 Years) Vaccine Recipients (Day 57) in Study P301 |
1012.5; 1845.9; 1782.6; 1669.1; 1890.2; 1618.3 | — |
| PRIMARY Parts 2 and 3: GM Concentration of Serum Pseudovirus Neutralizing Antibody VAC62 From Study P204 Vaccine Recipients at Day 57 Compared With Those From Young Adult (18 to 25 Years of Age) Vaccine Recipients (Day 57) in Study P301 |
1394.1; 1759.8; 4368.6; 1400.4 | — |
| PRIMARY Parts 1 and 2: Seroresponse Rate (SRR) For Serum Pseudovirus Neutralizing Antibody ID50 From Study P204 Vaccine Recipients at Day 57 Compared With Those From Young Adult (18 to 25 Years of Age) Vaccine Recipients (Day 57) in Study P301 |
99.5; 100; 100; 100; 100; 99.0 | — |
| PRIMARY Parts 2 and 3: SRR For Serum Pseudovirus Neutralizing Antibody VAC62 From Study P204 Vaccine Recipients at Day 57 Compared With Those From Young Adult (18 to 25 Years of Age) Vaccine Recipients (Day 57) in Study P301 |
98.9; 100; 88.5; 99.3 | — |
| PRIMARY Parts 1 and 2: GM Concentration of Post-booster Dose Serum Pseudovirus Neutralizing Antibody VAC62 in Study P204 Compared With Post-primary Series (Post-Dose 2) in Young Adult (18 to 25 Years of Age) Vaccine Recipients in Study P301 |
1400.4; 5457.2; 5575.9 | — |
| PRIMARY Part 3: GM Concentration of Post-third Dose Serum Pseudovirus Neutralizing Antibody VAC62 in Study P204 Compared With Post-primary Series (Post-Dose 2) in Young Adult (18 to 25 Years) Vaccine Recipients in Study P301 |
4616.6; 1400.4 | — |
| PRIMARY Parts 1 and 2: SRR for Post-booster Dose Serum Pseudovirus Neutralizing Antibody VAC62 From Baseline (Pre-Dose 1) Compared With Post-primary Series (Post-Dose 2) From Baseline (Pre-Dose 1) in Young Adult (18 to 25 Years) Vaccine Recipients in Study P301 |
99.3; 100; 100 | — |
| PRIMARY Part 3: SRR for Post-third Dose Serum Pseudovirus Neutralizing Antibody VAC62 From Baseline (Pre-Dose 1) Compared With Post-primary Series (Post-Dose 2) From Baseline (Pre-Dose 1) in Young Adult (18 to 25 Years) Vaccine Recipients in Study P301 |
90.0; 99.3 | — |
| SECONDARY Parts 1 and 2: GM Level of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) S Protein-specific Binding Antibody (bAb), as Measured by MesoScale Discovery (MSD) Electrochemiluminescence (ECL) Multiplex Assay on Days 1 and 57 |
35.6; 49.1; 15.8; 33.7; 14.6; 32.6 | — |
| SECONDARY Parts 1 and 2: GM Level of SARS-CoV-2 S Protein-specific bAb, as Measured by MSD ECL Multiplex Assay on Baseline (Pre-dose 1), Day 57, Day 209, BD-Day 1, and BD-Day 29 |
50.0; 37.5; 34.5; 51.9; 302128.3; 279427.6 | — |
| SECONDARY Part 3: GM Level of SARS-CoV-2 S Protein-specific bAb, as Measured by MSD ECL Multiplex Assay on Baseline (Pre-dose 1), Day 57, Third Dose-Day 1, Third Dose-Day 29, Third Dose-Day 181 |
4659.5; 141758.0; 48176.2; 93436.4; 40271.7 | — |
| SECONDARY Parts 1 and 2: GM Value of SARS-CoV-2-specific Neutralizing Antibody ID50 Titers on Day 1 and Day 57 |
9.3; 9.6; 9.3; 9.3; 9.6; 9.3 | — |
| SECONDARY Parts 2 and 3: GM Concentration of SARS-CoV-2-specific Neutralizing Antibody VAC62 on Day 1 and Day 57 |
7.9; 8.0; 21.5; 175.3; 199.9; 177.5 | — |
| SECONDARY Parts 1 and 2: GM Concentration of Post-booster SARS-CoV-2-specific Neutralizing Antibody VAC62 on Baseline, Day 57, Day 209, BD-Day 1, and BD-Day 29 |
9.0; 12.8; 7.8; 9.3; 1557.1; 1275.0 | — |
| SECONDARY Part 3: GM Concentration of Post-third Dose SARS-CoV-2-specific Neutralizing Antibody VAC62 on Baseline, Day 57, Third Dose-Day 1, Third Dose-Day 29, and Third Dose-Day 181 |
120.0; 3775.0; 1839.1; 4616.6; 1432.5 | — |
| SECONDARY Part 2: Number of Participants With SARS-CoV-2 Infection Including Symptomatic and Asymptomatic Infection (by Serology and/or RT-PCR) |
14; 13; 178; 330; 94; 198 | — |
| SECONDARY Part 2: Number of Participants With Asymptomatic SARS-CoV-2 Infection, Measured by RT-PCR and/or bAb Levels Against SARS-CoV-2 Nucleocapsid Protein (by Roche Elecsys) |
10; 10; 55; 124; 21; 70 | — |
| SECONDARY Part 2: Number of Participants With Occurrence of COVID-19 (Per US Centers for Disease Control and Prevention [CDC] Case Definition of COVID-19) |
4; 3; 125; 207; 73; 130 | — |
Summary
The primary goal for this study is to evaluate up to 3 dose levels of mRNA-1273 vaccine given to healthy children as intramuscular (IM) injection in 2 doses (in Parts 1 and 2) and 3 doses (in Part 3), and a third dose or an optional booster dose (BD) (in Parts 1 and 2).
Eligibility Criteria
Key Inclusion Criteria
- For participants with chronic diseases (such as, asthma, diabetes mellitus, cystic fibrosis, human immunodeficiency virus [HIV] infection), the disease should be stable, per investigator assessment.
- Investigator assessment that the parent(s)/legally acceptable representatives understand and are willing and physically able to comply with protocol mandated follow-up, including all procedures, written informed consent is provided, and participants provide assent.
- For children 2 years of age or older has a body mass index at or above the third percentile according to World Health Organization (WHO) Child Growth Standards at the Screening Visit.
- For children 6 months to <12 months of age: born at full-term with a minimum birth weight of 2.5 kilograms (kg).
- For female participants of childbearing potential: negative pregnancy test, adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first injection, agreement to continue adequate contraception or abstinence through 3 months following the second injection (Day 29) and the third dose in Part 3 (Day 149/booster dose Day 1), and not currently breastfeeding.
Key Exclusion Criteria
- Known history of SARS-CoV-2 infection within 2 weeks prior to administration of vaccine or known close contact with anyone with laboratory-confirmed SARS-CoV-2 infection or COVID-19 within 2 weeks prior to administration of vaccine.
- Prior administration of an investigational or approved CoV (such as, SARS-CoV-2, SARS CoV, Middle East Respiratory Syndrome CoV) vaccine.
- Treatment with investigational or approved agents for prophylaxis against COVID 19 (such as, receipt of SARS-CoV-2 monoclonal antibodies) within 6 months prior to enrollment.
- Known hypersensitivity to a component of the vaccine or its excipients.
- 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.
- History of a diagnosis or condition that, in the judgment of the investigator, may affect study endpoint assessment or compromise participant safety.
- Received any non-study vaccine within 14 days before or after any dose of vaccine (except for seasonal influenza vaccine, which is not permitted within 14 days before or after any dose of vaccine)
- Received intravenous or subcutaneous blood products (red blood cells, platelets, immunoglobulins) within 3 months prior to Day 1
- Participated in an interventional clinical study within 28 days prior to Day 0 or plans to donate blood products while participating in this study.
Data sourced from ClinicalTrials.gov (NCT04796896). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.