A Study to Investigate the Immunogenicity and Safety of mRNA COVID-19 Variant-containing Formulations

November 2, 2026 updated by: ModernaTX, Inc.

A Phase 3b/4, Open-label Study to Assess the Immunogenicity and Safety of mRNA COVID-19 Variant-containing Vaccine Formulations

The purpose of this study is to evaluate the immunogenicity and safety of mRNA-1283 and mRNA-1273 (variant formulations) within the current epidemiological environment

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

600

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

    • Kansas
      • Overland Park, Kansas, United States, 66209
        • Recruiting
        • Delricht Research @ Overland
    • Kentucky
      • Louisville, Kentucky, United States, 40205
        • Recruiting
        • Delricht Research @ Louisville
    • North Carolina
      • Charlotte, North Carolina, United States, 28210
        • Recruiting
        • Delricht Research @ Charlotte
    • Tennessee
      • Hendersonville, Tennessee, United States, 37075
        • Recruiting
        • Delricht Research @ Magnolia Family Medicine
    • Texas
      • Prosper, Texas, United States, 75078
        • Recruiting
        • Delricht Research @ Zomnir Family Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

12 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • ≥65 years of age at the time of signing the informed consent OR ≥12 to <65 years of age at the time of signing the informed consent with at least 1 risk factor for severe outcomes from COVID-19.
  • Female participants of childbearing potential may be enrolled in the study if not pregnant or breastfeeding, subject to other criteria specified in the study protocol.

Exclusion Criteria:

  • History of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection within 3 months prior to enrollment.

  • Acutely ill or febrile within 72 hours prior to or at Day 1.

  • History of a diagnosis or conditions that in the Investigator's opinion could affect participant's safety, assessment of endpoints, assessment of immune response, or adherence to study procedures.

  • Reported history of congenital or acquired immunodeficiency, immunosuppressive condition, asplenia, or recurrent severe infections.

  • History of coagulopathy or bleeding disorder that is considered a contraindication to IM injection or phlebotomy.

  • Receipt of any of the following:

    • COVID-19 vaccine within 3 months prior to enrollment,
    • Any licensed non COVID-19 vaccine within 28 days before or planned receipt within 28 days after the study intervention, except an influenza vaccine, which may be given 14 days before or after receipt of the study intervention,
    • Systemic immunosuppressive treatment within 180 days prior to the Screening or is anticipating the need for systemic immunosuppressive treatment at any time during participation in the study,
    • Systemic immunoglobulins, long-acting biological therapies that affect immune responses, or blood products within 90 days prior to the Day 1 Visit or plans for receipt during the study.

Note: Additional protocol-defined inclusion/exclusion criteria may apply.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: mRNA-1273 (Variant Formulation)

Participants will receive a single intramuscular (IM) injection of mRNA-1273 on Day 1.

Sterile liquid for injection

Other Names:
  • SPIKEVAX®
Experimental: mRNA-1283 (Variant Formulation)

Participants will receive a single IM injection of mRNA-1283 on Day 1.

Sterile liquid for injection

Other Names:
  • mNEXSPIKE®

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Geometric Mean Titer (GMT) of Neutralizing Antibody (nAb) Against Vaccine-matched Variant Formulation
Time Frame: Day 29
Day 29
Geometric Mean Fold Rise (GMFR) of Neutralizing Antibody (nAb) Against Vaccine-matched Variant Formulation
Time Frame: Day 29
Day 29

Secondary Outcome Measures

Outcome Measure
Time Frame
Number of Participants with Unsolicited Adverse Events (AEs)
Time Frame: Day 1 through Day 29
Day 1 through Day 29
Number of Participants with Serious AEs (SAEs), AEs Leading to Study Withdrawal, and AEs of Special Interest (AESIs)
Time Frame: Day 1 through Day 29/End of Study (EOS)
Day 1 through Day 29/End of Study (EOS)
Seroresponse Rate (SRR) of Neutralizing Antibody (nAb)
Time Frame: Day 29
Day 29

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 9, 2026

Primary Completion (Estimated)

December 11, 2026

Study Completion (Estimated)

December 11, 2026

Study Registration Dates

First Submitted

October 2, 2026

First Submitted That Met QC Criteria

October 2, 2026

First Posted (Actual)

October 7, 2026

Study Record Updates

Last Update Posted (Actual)

November 4, 2026

Last Update Submitted That Met QC Criteria

November 2, 2026

Last Verified

November 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • mRNA-1273_1283-P402

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.