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Investigating mRNA-1403 for preventing acute gastroenteritis in adults

A Phase 3, Randomized, Observer-blinded, Placebo-controlled Study to Evaluate the Safety and Efficacy of mRNA-1403, a Multivalent Candidate Vaccine to Prevent Norovirus Acute Gastroenteritis in Adults ≥18 Years of Age

Phase 3 Interventional ModernaTX, Inc. · NCT06592794

This study is testing a new vaccine called mRNA-1403 to see if it can help prevent norovirus stomach infections in adults.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment25000 (estimated)
Ages18 Years and up
SexAll
SponsorModernaTX, Inc. Industry-sponsored
Drugs / interventionsprednisone
Locations283 sites (Birmingham, Alabama and 282 other locations)
Trial IDNCT06592794 on ClinicalTrials.gov

What this trial studies

This study evaluates the safety and effectiveness of mRNA-1403, a vaccine designed to prevent moderate to severe norovirus acute gastroenteritis in adults aged 18 and older. Participants will receive either the mRNA-1403 vaccine or a placebo, and their health will be monitored to assess any adverse reactions and the vaccine's efficacy against specific norovirus strains. The study aims to provide insights into the potential of mRNA technology in preventing viral gastroenteritis.

Who should consider this trial

Good fit: Ideal candidates for this study are adults aged 18 and older who are medically stable and capable of complying with study protocols.

Not a fit: Patients with life-limiting diagnoses or those unable to comply with study requirements may not benefit from this study.

Why it matters

Potential benefit: If successful, this vaccine could significantly reduce the incidence of norovirus acute gastroenteritis in adults, improving overall public health.

How similar studies have performed: Other studies utilizing mRNA technology have shown promise in various vaccine applications, suggesting a potential for success in this novel approach to preventing gastroenteritis.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Participants who understand and are willing and physically able to comply with protocol mandated follow-up, including all procedures as assessed by the Investigator, and who are primarily responsible for their self-care and activities of daily living.
2. Participants may have chronic medical diagnoses but should be medically stable as assessed by the following criteria:

   * Absence of medical events associated with underlying diagnoses and qualifying as SAEs within 1 month prior to study intervention on Day 1.
   * Absence of known, current, and life-limiting diagnoses, which could continue for the duration of the study and which, in the opinion of the Investigator, would make completion of the protocol unlikely.
3. Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol.
4. Participants assigned female at birth are eligible to participate if they are not pregnant or breastfeeding/chestfeeding/bodyfeeding and meet protocol defined criteria.

Exclusion Criteria:

1. Participant is acutely ill or febrile (temperature ≥38.0 degrees Celsius (°C) \[100.4 degrees Fahrenheit \[°F\]) 72 hours prior to or at the Screening Visit or Day 1.
2. History of AGE within 14 days prior to Day 1 or close contact with an individual with AGE symptoms (in the home, socially, or occupationally) within 14 days prior to Day 1.
3. History of a diagnosis or condition that in the judgment of the Investigator, is clinically unstable or may affect participant safety, assessment of safety endpoints, assessment of immune response, or adherence to study procedures.
4. Current diagnosis of chronic gastrointestinal (GI) disease that is associated with ongoing symptoms of regular vomiting and/or diarrhea. Participants with stable, well-controlled chronic GI disease without regular vomiting and/or diarrhea can be considered for enrollment.
5. 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.
6. Has undergone surgical procedures within 7 days prior to Day 1 or is scheduled to undergo a surgical procedure within 28 days after study intervention.
7. Reported history of congenital or acquired immunodeficiency, immunocompromising/immunosuppressive condition, asplenia, or recurrent severe infections per protocol.
8. Reported history of anaphylaxis, urticaria, or other significant AR requiring medical intervention after receipt of a vaccine or intervention that includes one or more of the same components contained in the study vaccine.
9. History of myocarditis, pericarditis, or myopericarditis with onset within 180 days prior to Day 1 whose values have not returned to Baseline clinical status.
10. History of Guillain-Barré syndrome.
11. Reported history of coagulopathy or bleeding disorder considered a contraindication to IM injection or phlebotomy.
12. Dermatologic conditions that could affect local solicited AR assessments.
13. Diagnosis of malignancy within the previous 2 years (excluding nonmelanoma skin cancer).
14. Has received systemic immunosuppressive therapies for \>14 days in total within 6 months prior to Day 1 (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.
15. Has received or plans to receive any licensed vaccine ≤28 days prior to or within 28 days after study intervention (Day 1), except for influenza vaccines, which may be given 14 days before or after receipt of a study intervention.
16. Receipt of systemic immunoglobulins or blood products within 3 months prior to Day 1 or plans for receipt during the study.
17. Has donated ≥450 mL of blood products within 28 days prior to Day 1 Visit or plans to donate blood products during the study.
18. Participated in a clinical study with investigational treatment within 90 days prior to Day 1 (Baseline) based on the medical history interview or plans to do so while participating in this study. Participants may continue in prior interventional study follow-up activities, provided that it does not involve further investigational treatment and/or procedures that may affect safety and/or other study endpoints, and study participation does not result in a breach of either study protocol.
19. Is working as, has worked as, or is an immediate family member or household member of study personnel, Sponsor personnel, or study site staff directly involved with the conduct of the study.

Where this trial is running

Birmingham, Alabama and 282 other locations

+233 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Acute GastroenteritisNorovirus Acute GastroenteritismRNA-1403Viral Gastroenteritis
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.