A Study of Modified mRNA Vaccines in Healthy Adults

March 10, 2026 updated by: ModernaTX, Inc.

Study to Evaluate the Safety, Reactogenicity and Immunogenicity of Modified mRNA Vaccines Using a Systems Biology Approach in Healthy Adults

The main goal of this study is to evaluate the safety, reactogenicity, and immunogenicity of study vaccines.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

308

Phase

  • Phase 1

Contacts and Locations

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

Study Locations

  • United States
    • Florida
      • Hollywood, Florida, United States, 33024
        • CenExel
    • Georgia
      • Savannah, Georgia, United States, 31406
        • Meridian Clinical Research
    • Iowa
      • Sioux City, Iowa, United States, 51106
        • Meridian Clinical Research
    • Kansas
      • Lenexa, Kansas, United States, 66219
        • Johnson County Clinical Trials
    • Nebraska
      • Lincoln, Nebraska, United States, 68510
        • Meridian Clinical Research
    • Texas
      • Austin, Texas, United States, 78705
        • Benchmark Research
      • Austin, Texas, United States, 78745
        • Tekton Research, Inc
      • Houston, Texas, United States, 77081
        • DM Clinical Research- Texas Center for Drug Development

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

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Adults 18 to 75 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. For mRNA-1647 study arms, adults 18 to <50 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening.
  • Body mass index (BMI) of 18 kilograms (kg)/square meter (m^2) to 35 kg/m^2 (inclusive) at the screening visit.

Exclusion Criteria:

  • Participant has had close contact to someone with confirmed SARS-CoV-2, respiratory syncytial virus (RSV), or influenza infection in the past 14 days prior to the screening visit.
  • Severe allergic reaction to any component of the FLUAD vaccine (active comparator), including egg protein, or after a previous dose of any influenza vaccine.
  • Participant has received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (to include any systemic corticosteroids) or is anticipating the need for immunosuppressive treatment at any time during participation in the study.
  • Participant plans to receive any licensed or authorized vaccine, including COVID-19 influenza vaccines, within 28 days before or after any study injection.
  • Participant has received a NH 2021 - 2022 or 2022-2023 seasonal influenza vaccine or any other influenza vaccine, or an experimental RSV or cytomegalovirus (CMV) vaccine, within 6 months prior to study Day 1, and/or has not completed a primary vaccination series for COVID-19.
  • Participant has received an authorized or approved COVID-19 vaccine within 4 months prior to Day 1, and/or has not completed a primary vaccination series for COVID-19.
  • Participant had a laboratory-confirmed infection with influenza or RSV within 6 months prior to Day 1, or SARS-CoV-2 within 4 months of Day 1. SARS-CoV-2 infection confirmed with self-administered, authorized or approved rapid antigen test is acceptable.
  • Participant 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.
  • Participated in an interventional clinical study within 28 days prior to the screening visit based on the medical history interview or plans to do so while participating in this study until 12 months after their last study vaccination.

Other inclusion and 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: Part 1: mRNA-1345
Participants will receive single intramuscular (IM) injection of mRNA-1345 on Day 1.
Biological: mRNA-1345
Sterile liquid for injection
Experimental: Part 1: mRNA-1647 2-Dose
Participants will receive single IM injection of mRNA-1647 on Days 1 and 57.
Biological: mRNA-1647
Sterile lyophilized product
Experimental: Part 1: mRNA-1647 3-Dose
Participants will receive single IM injection of mRNA-1647 on Days 1, 57, and 169.
Biological: mRNA-1647
Sterile lyophilized product
Experimental: Part 2: mRNA-1273
Participants will receive single IM injection of mRNA-1273 on Day 1
Biological: mRNA-1273
Sterile liquid for injection
Experimental: Part 2: mRNA-1010
Participants will receive single IM injection of mRNA-1010 on Day 1.
Biological: mRNA-1010
Sterile liquid for injection
Active Comparator: Part 2: FLUAD®
Participants will receive single IM injection of FLUAD® on Day 1.
Biological: FLUAD®
adjuvanted (MF59), inactivated, quadrivalent seasonal influenza vaccine

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Number of Participants With Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)
Time Frame: Up to Day 176 (7 days follow-up post-vaccination)
Up to Day 176 (7 days follow-up post-vaccination)
Number of Participants With Unsolicited Adverse Events (AEs)
Time Frame: Up to Day 197 (28 days follow-up post-vaccination)
Up to Day 197 (28 days follow-up post-vaccination)
Number of Participants With Serious AEs (SAEs), AEs of Special Interest (AESIs), and AEs Leading to Study Withdrawal or Discontinuation of Study Vaccination
Time Frame: Day 1 through end of study (EOS) (up to Day 1249)
Day 1 through end of study (EOS) (up to Day 1249)
Number of Participants with Medically Attended Adverse Events (MAAEs)
Time Frame: Day 1 through Day 361
Day 1 through Day 361

Secondary Outcome Measures

Outcome Measure
Time Frame
Geometric Mean Titer (GMT) of Serum Neutralizing Antibody Response for mRNA-1010 (and Licensed Influenza Vaccine Comparator), mRNA-1273, and mRNA-1345
Time Frame: Days 1 (Baseline), 29, 85, and 197
Days 1 (Baseline), 29, 85, and 197
Geometric Mean Fold-Rise (GMFR) of Serum Neutralizing Antibody Response for mRNA-1010 (and Licensed Influenza Vaccine Comparator), mRNA-1273, and mRNA-1345
Time Frame: Days 1 (Baseline), 29, 85, and 197
Days 1 (Baseline), 29, 85, and 197
Percentage of Participants With Seroresponse for mRNA-1010 (and Licensed Influenza Vaccine Comparator), mRNA-1273, mRNA-1345, and mRNA-1647
Time Frame: Days 1 (Baseline), 29, 85, and 197
Days 1 (Baseline), 29, 85, and 197

Collaborators and Investigators

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

Sponsor

ModernaTX, Inc.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

May 24, 2022

Primary Completion (Actual)

February 27, 2026

Study Completion (Actual)

February 27, 2026

Study Registration Dates

First Submitted

May 25, 2022

First Submitted That Met QC Criteria

May 25, 2022

First Posted (Actual)

May 31, 2022

Study Record Updates

Last Update Posted (Actual)

March 12, 2026

Last Update Submitted That Met QC Criteria

March 10, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • mRNA-CRID-001

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.

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