SARS-CoV-2Phase 2NCT05137236
A Study to Evaluate the Immunogenicity and Safety of mRNA-1283 COVID-19 Vaccine Boosters
A Phase 2 study testing mRNA-1283, mRNA-1283.211 and mRNA-1273 in people with SARS-CoV-2, run by ModernaTX, Inc. at 17 sites in United States.
Trial summary
The main goal of Part A of this study is to assess the safety, reactogenicity, and immunogenicity of the study vaccine candidates. The main goal of Part B of this study is to assess the safety, reactogenicity, and immunogenicity of the mRNA-1283.529 booster vaccine candidate. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- SARS-CoV-2
- What is being tested?
- mRNA-1283, mRNA-1283.211 and mRNA-1273
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 540 participants
- Where
- 17 sitesUnited States
- Study dates
- 6 Dec 2021to 23 Mar 2023
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Female participants of nonchildbearing potential may be enrolled in the study. Nonchildbearing potential is defined as bilateral tubal ligation >1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause.
- Female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (Day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to Day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding.
- Participant must have received their second dose of the mRNA-1273 primary series at least 6 months prior to screening and enrollment (Part A) or have received the mRNA-1273 series and an mRNA-1273 booster dose at least 3 months prior to screening and enrollment (Part B).
Who cannot join
- Had significant exposure to someone with SARS-CoV-2 infection or COVID-19 in the past 14 days, defined by the US Centers for Disease Control and Prevention (CDC) as a close contact of someone who has COVID-19.
- Is acutely ill or febrile (temperature ≥38.0 degree Celsius [°C]/100.4 degree Fahrenheit [°F]) less than 72 hours prior to or at the screening visit or Day 1.
- Has a medical, psychiatric, or occupational condition that may pose additional risk as a result of participation, or that could interfere with safety assessments or interpretation of results according to the investigator's judgment.
- Has received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids ≥10 milligrams [mg]/day of prednisone equivalent) or is anticipating the need for immunosuppressive treatment at any time during participation in the study.
- Has received or plans to receive any licensed vaccine ≤28 days prior to the injection (Day 1) or plans to receive a licensed vaccine within 28 days before or after the study injection, with the exception of influenza vaccines, which may be given 14 days before or after receipt of a study vaccine.
- Has received systemic immunoglobulins or blood products within 3 months prior to the screening visit, or plans to receive these during the study.
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- Has donated ≥ 450 milliliters (mL) of blood products within 28 days prior to the screening visit or plans to donate blood products during the study.
- Plans to participate in an interventional clinical trial of an investigational vaccine or drug while participating in this study.
- Note: Other inclusion and exclusion criteria may apply.
Trial locations and contacts
17 sites in 1 country.
17 sites in 1 country
United States17 sites
MedPharmics, LLC. - Albuquerque
Albuquerque, New Mexico, 87102-3876
Tekton Research
Chamblee, Georgia, 30341
CTI Clinical Research Center
Cincinnati, Ohio, 45212
Meridian Clinical Research (Cincinnati)
Cincinnati, Ohio, 45246-2316
Aventiv Research Inc
Columbus, Ohio, 43213-6517
ACRC Trials
Frisco, Texas, 75033-4135
Research Centers of America
Hollywood, Florida, 33024-2709
Ventavia Research Group
Houston, Texas, 77008
Meridian Clinical Research (Nebraska)
Lincoln, Nebraska, 68510
MedPharmics
Metairie, Louisiana, 70006
Clinical Research Institute, Inc - CRN
Minneapolis, Minnesota, 55402-2700
Health Research of Hampton Roads Inc.
Newport News, Virginia, 23606-4537
Coastal Carolina Research Center
North Charleston, South Carolina, 29405-4986
MedPharmics, LLC
Phoenix, Arizona, 85015-1105
Rochester Clinical Research, Inc.
Rochester, New York, 14609
Precision Clinical Research
Sunrise, Florida, 33351-7311
UMass Memorial Medical Center
Worcester, Massachusetts, 01655-0002
About this study
Official title: A Phase 2A, Randomized, Stratified, Observer-Blind Study to Evaluate the Immunogenicity and Safety of mRNA-1283 Vaccine Boosters for SARS-CoV-2
The main goal of Part A of this study is to assess the safety, reactogenicity, and immunogenicity of the study vaccine candidates. The main goal of Part B of this study is to assess the safety, reactogenicity, and immunogenicity of the mRNA-1283.529 booster vaccine candidate.
Read the detailed description
Part A of this study will assess whether a single dose of mRNA-1283 at three different dose levels or mRNA-1283.211 at two different dose levels will boost antibody responses to the Wuhan-Hu-1 (ancestral strain of SARS-CoV-2) virus, and to the B.1.351 variant, and potentially other SARS-CoV-2 variants, and it will also be used to select a dose for subsequent clinical evaluation. The study will include an active comparator group of participants who will receive mRNA-1273.
Participants in Part A who received the primary series of mRNA-1273 with appropriate documentation at least 6 months prior will be randomized 1:1:1:1:1:1 to receive a single boost of mRNA-1283 at one of three dose levels, a single boost of mRNA-1283.211 at one of two dose levels, or a single dose of the active comparator, mRNA-1273.
Part B of this study will assess whether a single dose of mRNA-1283.529 at two different dose levels as the second booster after a first booster of mRNA- 1273, at least 3 months prior, will boost antibody response to the ancestral strain of the SARS-CoV-2 virus, the B.1.1.529 variant, and potentially other SARS-CoV-2 variants, and inform dose selection for mRNA-1283.529 booster vaccine candidate for subsequent clinical evaluation.
Participants in Part B who received the primary series of mRNA 1273 and who received a first booster dose of mRNA-1273 at least 3 months prior will be enrolled in a 1:1 ratio to receive a single boost of mRNA 1283.529 at one of two dose levels.
- Conditions
- SARS-CoV-2
- Being tested
- mRNA-1283, mRNA-1283.211, mRNA-1273, mRNA-1283.529
- Keywords
- mRNA-1273, mRNA-1273 vaccine, SARS-CoV-2, SARS-CoV-2 Vaccine, Coronavirus, Virus Diseases, Messenger RNA, COVID-19, COVID-19 Vaccine, Moderna
- Medical subject headings
- Coronavirus Infections, Virus Diseases, COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
mRNA-1283Biological
Sterile liquid for injection
mRNA-1283.211Biological
Sterile liquid for injection
mRNA-1273Biological
Sterile liquid for injection
mRNA-1283.529Biological
Sterile liquid for injection
| Study group | Role | What they receive |
|---|---|---|
| Part A: mRNA-1283 Dose Level 1 | Experimental | Participants will receive single intramuscular (IM) injection of mRNA-1283 at Dose Level 1 on Day 1. Receives: Biological: mRNA-1283 |
| Part A: mRNA-1283 Dose Level 2 | Experimental | Participants will receive single IM injection of mRNA-1283 at Dose Level 2 on Day 1. Receives: Biological: mRNA-1283 |
| Part A: mRNA-1283 Dose Level 3 | Experimental | Participants will receive single IM injection of mRNA-1283 at Dose Level 3 on Day 1. Receives: Biological: mRNA-1283 |
| Part A: mRNA-1283.211 Dose Level 1 | Experimental | Participants will receive single IM injection of mRNA-1283.211 at Dose Level 1 on Day 1. Receives: Biological: mRNA-1283.211 |
| Part A: mRNA-1283.211 Dose Level 2 | Experimental | Participants will receive single IM injection of mRNA-1283.211 at Dose Level 2 on Day 1. Receives: Biological: mRNA-1283.211 |
| Part A: mRNA-1273 | Active comparator | Participants will receive single IM injection of mRNA-1273 on Day 1. Receives: Biological: mRNA-1273 |
| Part B: mRNA-1283.529 Dose Level 1 | Experimental | Participants will receive single IM injection of mRNA-1283.529 as a second booster at Dose Level 1 on Day 1. Receives: Biological: mRNA-1283.529 |
| Part B: mRNA-1283.529 Dose Level 2 | Experimental | Participants will receive single IM injection of mRNA-1283.529 as a second booster at Dose Level 2 on Day 1. Receives: Biological: mRNA-1283.529 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Parts A and B: Number of Participants With Solicited Local and Solicited Systemic Reactogenicity Adverse Reactions (ARs)
An AR is any adverse event (AE) related to the IP injection. Solicited local ARs included pain at injection site, erythema (redness) at injection site, swelling (hardness) at injection site, localized axillary swelling or tenderness ipsilateral to the injection arm, and groin or underarm swelling or tenderness ipsilateral to the side of injection. Solicited systemic ARs included headache, fatigue, myalgia (muscle aches all over the body), arthralgia (aching in several joints), nausea/vomiting, fever, chills, irritability/crying, sleepiness, and loss of appetite. Note, not all solicited ARs were considered AEs. The Investigator determined if solicited AR was also to be recorded as an AE. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.
Measured: Up to Day 7
Parts A and B: Number of Participants With Unsolicited AEs
An unsolicited AE was defined as any AE reported by the participant that was not specified as a solicited AR in the protocol or was specified as a solicited AR but started outside the protocol-defined period for reporting solicited ARs. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.
Measured: Up to Day 28
Parts A and B: Number of Participants With Serious Adverse Events (SAEs), Medically Attended AEs (MAAEs), AEs Leading to Withdrawal From Study Participation and AEs of Special Interest (AESIs)
SAEs were AEs that resulted in death, were life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, a congenital anomaly or birth defect, or was a medically important event. MAAEs were AEs that lead to an unscheduled visit to a healthcare provider. AESIs were AEs (serious or nonserious) of scientific and medical concern specific to the Sponsor's product or program for which ongoing monitoring and immediate notification by the investigator to the Sponsor was required. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.
Measured: Day 1 to Day 366
Part A: Geometric Mean Titer (GMT) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Specific Neutralizing Antibody (nAb) Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
The GMT (50% inhibitory dose [ID50]) of nAb against ancestral SARS-CoV-2 and against SARS-CoV-2 variant B.1.351 are reported.
Measured: Day 29
Part A: Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
The GMFR measures the changes in immunogenicity titers or levels within participants.
Measured: Day 29
Part A: Number of Participants With Seroresponse Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Seroresponse was defined as an increase of SARS-CoV-2 specific binding antibody (bAb) level or nAb titer to at least 4x lower limit of quantification (LLOQ) if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.
Measured: Day 29
Part B: GMT of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
The GMT (ID50) of nAb against SARS-CoV-2 omicron variant (B.1.1.529) are reported.
Measured: Day 29
Part B: GMFR of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
The GMFR measures the changes in immunogenicity titers or levels within participants.
Measured: Day 29
Part B: Number of Participants With Seroresponse Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Seroresponse was defined as an increase of SARS-CoV-2 specific bAb level or nAb titer to at least 4x LLOQ if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.
Measured: Day 29
Secondary outcomes (10)
Part A: GMT of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
The GMT (ID50) of nAb against ancestral SARS-CoV-2 and against SARS-CoV-2 Variant B.1.351 are reported.
Measured: Days 1, 29, 91, 181, and 366
Part A: GMT of SARS-CoV-2 Specific bAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
The GMT of bAb against ancestral SARS-CoV-2 and against SARS-CoV-2 Variant B.1.351 are reported.
Measured: Days 1, 29, 91, 181, and 366
Part B: GMT of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
The GMT (ID50) of nAb against SARS-CoV-2 omicron variant (B.1.1.529) are reported.
Measured: Days 1, 29, 91, 181, and 366
Part B: GMT of SARS-CoV-2 Specific bAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
The GMT of bAb against SARS-CoV-2 omicron variant (B.1.1.529) are reported.
Measured: Days 1, 29, 91, 181, and 366
Part A: GMFR of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
The GMFR measures the changes in immunogenicity titers or levels within participants.
Measured: Days 29, 91, 181, and 366
Part A: GMFR of SARS-CoV-2 Specific bAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
The GMFR measures the changes in immunogenicity titers or levels within participants.
Measured: Days 29, 91, 181, and 366
Part B: GMFR of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
The GMFR measures the changes in immunogenicity titers or levels within participants.
Measured: Days 29, 91, 181, and 366
Part B: GMFR of SARS-CoV-2 Specific bAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
The GMFR measures the changes in immunogenicity titers or levels within participants.
Measured: Days 29, 91, 181, and 366
Part A: Number of Participants With Seroresponse Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Seroresponse was defined as an increase of SARS-CoV-2 specific bAb level or nAb titer to at least 4x LLOQ if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.
Measured: Days 29, 91, 181, and 366
Part B: Number of Participants With Seroresponse Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Seroresponse was defined as an increase of SARS-CoV-2 specific bAb level or nAb titer to at least 4x LLOQ if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.
Measured: Days 29, 91, 181, and 366
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Nov 2021
- Study start6 Dec 2021
- Primary completion23 Mar 2023
- Study completion23 Mar 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (3)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 2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 540 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
- NCT05137236
- Sponsor's protocol ID
- mRNA-1283-P201
- Status last verified
- Jun 2025
- First submitted
- 24 Nov 2021
- Last updated
- 17 Jul 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Publications
Chalkias S, Pragalos A, Akinsola A, Berman G, Ampajwala M, Meyer J, Schoch L, Zhou W, Paila YD, Deng W, Feng J, de Windt E, Edwards D, Miller J, Das R. Safety and Immunogenicity of SARS-CoV-2 Spike Receptor-Binding Domain and N-Terminal Domain mRNA Vaccine. J Infect Dis. 2025 Apr 15;231(4):e754-e763. doi: 10.1093/infdis/jiaf022.
PubMed 39792478Stewart-Jones GBE, Elbashir SM, Wu K, Lee D, Renzi I, Ying B, Koch M, Sein CE, Choi A, Whitener B, Garcia-Dominguez D, Henry C, Woods A, Ma L, Montes Berrueta D, Avena LE, Quinones J, Falcone S, Hsiao CJ, Scheaffer SM, Thackray LB, White P, Diamond MS, Edwards DK, Carfi A. Domain-based mRNA vaccines encoding spike protein N-terminal and receptor binding domains confer protection against SARS-CoV-2. Sci Transl Med. 2023 Sep 13;15(713):eadf4100. doi: 10.1126/scitranslmed.adf4100. Epub 2023 Sep 13.
PubMed 37703353Stewart-Jones GBE, Elbashir SM, Wu K, Lee D, Renzi I, Ying B, Koch M, Sein CE, Choi A, Whitener B, Garcia-Dominguez D, Henry C, Woods A, Ma L, Montes Berrueta D, Avena LE, Quinones J, Falcone S, Hsiao CJ, Scheaffer SM, Thackray LB, White P, Diamond MS, Edwards DK, Carfi A. Development of SARS-CoV-2 mRNA vaccines encoding spike N-terminal and receptor binding domains. bioRxiv [Preprint]. 2022 Oct 7:2022.10.07.511319. doi: 10.1101/2022.10.07.511319.
PubMed 36238717
Study at a glance
From the registry record, last updated by the sponsor on 17 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2A, Randomized, Stratified, Observer-Blind Study to Evaluate the Immunogenicity and Safety of mRNA-1283 Vaccine Boosters for SARS-CoV-2
- ClinicalTrials.gov ID
- NCT05137236
- Acronym / sponsor ID
- mRNA-1283-P201
- Conditions
- SARS-CoV-2
- Keywords
- mRNA-1273, mRNA-1273 vaccine, SARS-CoV-2, SARS-CoV-2 Vaccine, Coronavirus, Virus Diseases, Messenger RNA, COVID-19
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 540 participants (actual)
- Lead sponsor
- ModernaTX, Inc.Industry (pharma, biotech, devices)
- Study start
- 6 Dec 2021 (actual)
- Primary completion
- 23 Mar 2023 (actual)
- Study completion
- 23 Mar 2023 (actual)
- First posted
- 30 Nov 2021 (actual)
- Results
- Posted 17 Jul 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The main goal of Part A of this study is to assess the safety, reactogenicity, and immunogenicity of the study vaccine candidates. The main goal of Part B of this study is to assess the safety, reactogenicity, and immunogenicity of the mRNA-1283.529 booster vaccine candidate.
Detailed description
Part A of this study will assess whether a single dose of mRNA-1283 at three different dose levels or mRNA-1283.211 at two different dose levels will boost antibody responses to the Wuhan-Hu-1 (ancestral strain of SARS-CoV-2) virus, and to the B.1.351 variant, and potentially other SARS-CoV-2 variants, and it will also be used to select a dose for subsequent clinical evaluation. The study will include an active comparator group of participants who will receive mRNA-1273.
Participants in Part A who received the primary series of mRNA-1273 with appropriate documentation at least 6 months prior will be randomized 1:1:1:1:1:1 to receive a single boost of mRNA-1283 at one of three dose levels, a single boost of mRNA-1283.211 at one of two dose levels, or a single dose of the active comparator, mRNA-1273.
Part B of this study will assess whether a single dose of mRNA-1283.529 at two different dose levels as the second booster after a first booster of mRNA- 1273, at least 3 months prior, will boost antibody response to the ancestral strain of the SARS-CoV-2 virus, the B.1.1.529 variant, and potentially other SARS-CoV-2 variants, and inform dose selection for mRNA-1283.529 booster vaccine candidate for subsequent clinical evaluation.
Participants in Part B who received the primary series of mRNA 1273 and who received a first booster dose of mRNA-1273 at least 3 months prior will be enrolled in a 1:1 ratio to receive a single boost of mRNA 1283.529 at one of two dose levels.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 8
| Arm | Type | Receives |
|---|---|---|
| Part A: mRNA-1283 Dose Level 1 | Experimental | Biological: mRNA-1283Participants will receive single intramuscular (IM) injection of mRNA-1283 at Dose Level 1 on Day 1. |
| Part A: mRNA-1283 Dose Level 2 | Experimental | Biological: mRNA-1283Participants will receive single IM injection of mRNA-1283 at Dose Level 2 on Day 1. |
| Part A: mRNA-1283 Dose Level 3 | Experimental | Biological: mRNA-1283Participants will receive single IM injection of mRNA-1283 at Dose Level 3 on Day 1. |
| Part A: mRNA-1283.211 Dose Level 1 | Experimental | Biological: mRNA-1283.211Participants will receive single IM injection of mRNA-1283.211 at Dose Level 1 on Day 1. |
| Part A: mRNA-1283.211 Dose Level 2 | Experimental | Biological: mRNA-1283.211Participants will receive single IM injection of mRNA-1283.211 at Dose Level 2 on Day 1. |
| Part A: mRNA-1273 | Active comparator | Biological: mRNA-1273Participants will receive single IM injection of mRNA-1273 on Day 1. |
| Part B: mRNA-1283.529 Dose Level 1 | Experimental | Biological: mRNA-1283.529Participants will receive single IM injection of mRNA-1283.529 as a second booster at Dose Level 1 on Day 1. |
| Part B: mRNA-1283.529 Dose Level 2 | Experimental | Biological: mRNA-1283.529Participants will receive single IM injection of mRNA-1283.529 as a second booster at Dose Level 2 on Day 1. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Female participants of nonchildbearing potential may be enrolled in the study. Nonchildbearing potential is defined as bilateral tubal ligation >1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause.
- Female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (Day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to Day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding.
- Participant must have received their second dose of the mRNA-1273 primary series at least 6 months prior to screening and enrollment (Part A) or have received the mRNA-1273 series and an mRNA-1273 booster dose at least 3 months prior to screening and enrollment (Part B).
Key exclusion criteria (9 listed)
- Had significant exposure to someone with SARS-CoV-2 infection or COVID-19 in the past 14 days, defined by the US Centers for Disease Control and Prevention (CDC) as a close contact of someone who has COVID-19.
- Is acutely ill or febrile (temperature ≥38.0 degree Celsius [°C]/100.4 degree Fahrenheit [°F]) less than 72 hours prior to or at the screening visit or Day 1.
- Has a medical, psychiatric, or occupational condition that may pose additional risk as a result of participation, or that could interfere with safety assessments or interpretation of results according to the investigator's judgment.
- Has received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids ≥10 milligrams [mg]/day of prednisone equivalent) or is anticipating the need for immunosuppressive treatment at any time during participation in the study.
- Has received or plans to receive any licensed vaccine ≤28 days prior to the injection (Day 1) or plans to receive a licensed vaccine within 28 days before or after the study injection, with the exception of influenza vaccines, which may be given 14 days before or after receipt of a study vaccine.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| mRNA-1283Sterile liquid for injection | Biological | Part A: mRNA-1283 Dose Level 1, Part A: mRNA-1283 Dose Level 2, Part A: mRNA-1283 Dose Level 3 |
| mRNA-1283.211Sterile liquid for injection | Biological | Part A: mRNA-1283.211 Dose Level 1, Part A: mRNA-1283.211 Dose Level 2 |
| mRNA-1273Sterile liquid for injection | Biological | Part A: mRNA-1273 |
| mRNA-1283.529Sterile liquid for injection | Biological | Part B: mRNA-1283.529 Dose Level 1, Part B: mRNA-1283.529 Dose Level 2 |
Primary outcome
Parts A and B: Number of Participants With Solicited Local and Solicited Systemic Reactogenicity Adverse Reactions (ARs)
Time frame: Up to Day 7
An AR is any adverse event (AE) related to the IP injection. Solicited local ARs included pain at injection site, erythema (redness) at injection site, swelling (hardness) at injection site, localized axillary swelling or tenderness ipsilateral to the injection arm, and groin or underarm swelling or tenderness ipsilateral to the side of injection. Solicited systemic ARs included headache, fatigue, myalgia (muscle aches all over the body), arthralgia (aching in several joints), nausea/vomiting, fever, chills, irritability/crying, sleepiness, and loss of appetite. Note, not all solicited ARs were considered AEs. The Investigator determined if solicited AR was also to be recorded as an AE. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.
Parts A and B: Number of Participants With Unsolicited AEs
Time frame: Up to Day 28
An unsolicited AE was defined as any AE reported by the participant that was not specified as a solicited AR in the protocol or was specified as a solicited AR but started outside the protocol-defined period for reporting solicited ARs. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.
Parts A and B: Number of Participants With Serious Adverse Events (SAEs), Medically Attended AEs (MAAEs), AEs Leading to Withdrawal From Study Participation and AEs of Special Interest (AESIs)
Time frame: Day 1 to Day 366
SAEs were AEs that resulted in death, were life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, a congenital anomaly or birth defect, or was a medically important event. MAAEs were AEs that lead to an unscheduled visit to a healthcare provider. AESIs were AEs (serious or nonserious) of scientific and medical concern specific to the Sponsor's product or program for which ongoing monitoring and immediate notification by the investigator to the Sponsor was required. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.
Part A: Geometric Mean Titer (GMT) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Specific Neutralizing Antibody (nAb) Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Time frame: Day 29
The GMT (50% inhibitory dose [ID50]) of nAb against ancestral SARS-CoV-2 and against SARS-CoV-2 variant B.1.351 are reported.
Part A: Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Time frame: Day 29
The GMFR measures the changes in immunogenicity titers or levels within participants.
Part A: Number of Participants With Seroresponse Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Time frame: Day 29
Seroresponse was defined as an increase of SARS-CoV-2 specific binding antibody (bAb) level or nAb titer to at least 4x lower limit of quantification (LLOQ) if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.
Part B: GMT of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Time frame: Day 29
The GMT (ID50) of nAb against SARS-CoV-2 omicron variant (B.1.1.529) are reported.
Part B: GMFR of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Time frame: Day 29
The GMFR measures the changes in immunogenicity titers or levels within participants.
Part B: Number of Participants With Seroresponse Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Time frame: Day 29
Seroresponse was defined as an increase of SARS-CoV-2 specific bAb level or nAb titer to at least 4x LLOQ if the baseline is below the LLOQ, or a 4-fold or greater rise if pre-booster ≥ LLOQ.
10 secondary outcomes
Part A: GMT of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Time frame: Days 1, 29, 91, 181, and 366
Part A: GMT of SARS-CoV-2 Specific bAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Time frame: Days 1, 29, 91, 181, and 366
Part B: GMT of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Time frame: Days 1, 29, 91, 181, and 366
Part B: GMT of SARS-CoV-2 Specific bAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Time frame: Days 1, 29, 91, 181, and 366
Part A: GMFR of SARS-CoV-2 Specific nAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Time frame: Days 29, 91, 181, and 366
Part A: GMFR of SARS-CoV-2 Specific bAb Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Time frame: Days 29, 91, 181, and 366
Part B: GMFR of SARS-CoV-2 Specific nAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Time frame: Days 29, 91, 181, and 366
Part B: GMFR of SARS-CoV-2 Specific bAb Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Time frame: Days 29, 91, 181, and 366
Part A: Number of Participants With Seroresponse Against Ancestral SARS-CoV-2 and Against SARS-CoV-2 Variant B.1.351
Time frame: Days 29, 91, 181, and 366
Part B: Number of Participants With Seroresponse Against SARS-CoV-2 Omicron Variant (B.1.1.529)
Time frame: Days 29, 91, 181, and 366
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Jul 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 39792478Chalkias S, Pragalos A, Akinsola A, Berman G, Ampajwala M, Meyer J, Schoch L, Zhou W, Paila YD, Deng W, Feng J, de Windt E, Edwards D, Miller J, Das R. Safety and Immunogenicity of SARS-CoV-2 Spike Receptor-Binding Domain and N-Terminal Domain mRNA Vaccine. J Infect Dis. 2025 Apr 15;231(4):e754-e763. doi: 10.1093/infdis/jiaf022.
- Derived from this study: PubMed 37703353Stewart-Jones GBE, Elbashir SM, Wu K, Lee D, Renzi I, Ying B, Koch M, Sein CE, Choi A, Whitener B, Garcia-Dominguez D, Henry C, Woods A, Ma L, Montes Berrueta D, Avena LE, Quinones J, Falcone S, Hsiao CJ, Scheaffer SM, Thackray LB, White P, Diamond MS, Edwards DK, Carfi A. Domain-based mRNA vaccines encoding spike protein N-terminal and receptor binding domains confer protection against SARS-CoV-2. Sci Transl Med. 2023 Sep 13;15(713):eadf4100. doi: 10.1126/scitranslmed.adf4100. Epub 2023 Sep 13.
- Derived from this study: PubMed 36238717Stewart-Jones GBE, Elbashir SM, Wu K, Lee D, Renzi I, Ying B, Koch M, Sein CE, Choi A, Whitener B, Garcia-Dominguez D, Henry C, Woods A, Ma L, Montes Berrueta D, Avena LE, Quinones J, Falcone S, Hsiao CJ, Scheaffer SM, Thackray LB, White P, Diamond MS, Edwards DK, Carfi A. Development of SARS-CoV-2 mRNA vaccines encoding spike N-terminal and receptor binding domains. bioRxiv [Preprint]. 2022 Oct 7:2022.10.07.511319. doi: 10.1101/2022.10.07.511319.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
17 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing mRNA-1283, mRNA-1283.211 and mRNA-1273 in people with SARS-CoV-2, run by ModernaTX, Inc. at 17 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 17 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 17 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Parts A and B: Number of Participants With Solicited Local and Solicited Systemic Reactogenicity Adverse Reactions (ARs) (time frame: Up to Day 7). The study lists 9 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05137236, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Jul 2025.