A Study to Evaluate the Safety and Immunogenicity of the mRNA-1273.214 COVID-19 Vaccine in Healthy Children Between 6 Months to Less Than 6 Years of Age
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The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT05436834 |
Recruitment Status :
Active, not recruiting
First Posted : June 29, 2022
Last Update Posted : May 23, 2023
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Condition or disease | Intervention/treatment | Phase |
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SARS-CoV-2 | Biological: mRNA-1273.214 | Phase 3 |
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 and will be followed for approximately 12 months after the second dose for safety and additional immunogenicity follow-up.
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. Participants will receive a single booster dose of the mRNA-1273.214 vaccine, at least 4 months after completion of the mRNA-1273 primary series and will be followed for approximately 6 months after the booster dose for safety and immunogenicity.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 931 participants |
Allocation: | N/A |
Intervention Model: | Sequential Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Prevention |
Official Title: | An Open-Label, Phase 3 Study to Evaluate the Safety and Immunogenicity of the mRNA-1273.214 Vaccine for SARS-CoV-2 Variants of Concern in Participants Aged 6 Months to < 6 Years |
Actual Study Start Date : | June 21, 2022 |
Estimated Primary Completion Date : | June 28, 2024 |
Estimated Study Completion Date : | June 28, 2024 |

Arm | Intervention/treatment |
---|---|
Experimental: mRNA-1273.214
Part 1: Participants who have not been previously vaccinated against SARS-CoV-2, will receive 2 intramuscular (IM) injections of 25 microgram (μg) mRNA-1273.214 on Day 1 and Day 29. Part 2: Participants who have previously been vaccinated with a mRNA-1273 primary series, will receive a single IM booster dose (BD) of 10 μg mRNA-1273.214 at least 4 months after the last dose on BD Day 1. |
Biological: mRNA-1273.214
Sterile liquid for injection |
- Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs) [ Time Frame: Up to Day 8 (7 days post-vaccination) ]
- Number of Participants with Unsolicited Adverse Events (AEs) [ Time Frame: Up to Day 29 (28 days after each injection) ]
- Number of Participants with Medically-Attended AEs (MAAEs) [ Time Frame: Up to Day 575 ]
- Number of Participants with Serious AEs (SAEs) [ Time Frame: Up to Day 575 ]
- Number of Participants with Adverse Events of Special Interest (AESI) [ Time Frame: Up to Day 575 ]
- Number of Participants with AEs Leading to Withdrawal [ Time Frame: Up to Day 575 ]
- Geometric Mean (GM) of the Serum Antibody (Ab) Level Against SARS-CoV-2 (Omicron BA.1 and Ancestral SARS-CoV-2) [ Time Frame: Day 57 (28 days after second dose) ]
- GM of the Serum Ab Level Against SARS-CoV-2 (Omicron BA.1 and Ancestral SARS-CoV-2) [ Time Frame: Day 29 (28 days after booster dose) ]
- SRR of Vaccine Recipients of SARS-CoV-2 VOC (Omicron BA.1 and Ancestral SARS-CoV-2) [ Time Frame: Day 29 (28 days after booster dose) ]
- Seroresponse Rate (SRR) of Vaccine Recipients of SARS-CoV-2 VOC (Omicron BA.1 and Ancestral SARS-CoV-2) [ Time Frame: Day 57 (28 days after second dose) ]

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 6 Months to 5 Years (Child) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- 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. This includes inability to draw baseline blood samples (minimum amount needed).
- The participant is 2 years or older and has a body mass index (BMI) at or above the 2nd 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 2nd percentile according to WHO Child Growth Standards at the Screening Visit.
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).
Inclusion criteria for Part 2:
- The participant must have received 2 doses of mRNA-1273, approximately 28 to 35 days apart, as 25-μg primary series, and 2nd dose was given at least 4 months prior to enrollment.
Exclusion Criteria:
- Has a known history of SARS-CoV-2 infection (that is, reported AE of coronavirus disease 2019 [COVID-19] or asymptomatic SARS-CoV-2 infection during Study mRNA-1273-P204) 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°C/≥ 100.4°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.
- 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, this applies to vaccines other than the 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)
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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.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05436834

Responsible Party: | ModernaTX, Inc. |
ClinicalTrials.gov Identifier: | NCT05436834 |
Other Study ID Numbers: |
mRNA-1273-P306 |
First Posted: | June 29, 2022 Key Record Dates |
Last Update Posted: | May 23, 2023 |
Last Verified: | May 2023 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |