Effectiveness of mRNA-1273 Variant-Containing Vaccine Formulation Against Severe Outcomes in Adults Aged 50-64 Years Without Risk Factors for Severe COVID-19 (DAN-COVID)

March 13, 2026 updated by: Tor Biering-Sørensen

A Phase 4 Pragmatic, Randomized Trial to Evaluate the Effectiveness of mRNA-1273 Variant-Containing Vaccine Formulation Against Severe Outcomes in Adults Aged 50-64 Years Without Risk Factors for Severe COVID-19

The purpose of this pragmatic randomized trial is to evaluate the vaccine effectiveness of the COVID-19 vaccine, mRNA-1273, in adults aged 50-64 years without known risk factors for severe COVID-19 infection. Participants will be randomized 1:1 to either COVID-19 vaccine or no COVID-19 vaccine.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The study is a pragmatic, registry-based, open-label, individually randomized trial. The Danish nationwide administrative health registries will be used for data collection including baseline information, follow-up data, and safety monitoring. The study aims to randomize a total of 285,000 participants. Participants will be individually randomized 1:1 to receive either a COVID-19 vaccine or no COVID-19 vaccine. The study is designed to assess the vaccine effectiveness of the COVID-19 vaccine vs. no COVID-19 vaccine on the risk of medically attended COVID-19 infection.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
285000

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Denmark
      • Hellerup, Denmark, 2900
        • Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte
      • Søborg, Denmark, 2860
        • Danske Lægers Vaccinations Service

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Age 50-64 years
  • Informed consent form has been signed and dated

Exclusion Criteria:

  • Medical conditions that increase the risk of severe COVID-19, which will be assessed through self-reporting. These medical conditions include:

    1. Asthma
    2. Cancer (excluding non-melanoma skin cancer)
    3. Cardiomyopathies
    4. Cerebrovascular disease
    5. Chronic kidney disease
    6. Chronic lung disease
    7. Cystic Fibrosis
    8. Dementia
    9. Diabetes
    10. Down syndrome
    11. Heart failure
    12. Human Immunodeficiency Virus
    13. Immunosuppressive therapy
    14. Ischemic heart disease
    15. Liver disease
    16. Neurological/neuromuscular disease
    17. Psychiatric disease (psychotic, schizophrenic, schizotypal, depressive, and bipolar (affective) disorders).
    18. Severe obesity (body mass index >35 kg/m2)
    19. Severe substance abuse
    20. Short bowel syndrome
    21. Solid organ transplant or hematological transplant
  • Apart from these, there are no specific exclusion criteria for this study

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: mRNA-1273 (Spikevax)
COVID-19 vaccine single injection at day 0
Biological: mRNA-1273 (Moderna COVID-19 vaccine)
For this arm, the current variant formulation of Spikevax (mRNA-1273) vaccine will be used.
No Intervention: No COVID-19 vaccine (control)
Control arm, no COVID-19 vaccine

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Medically attended COVID-19
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Defined as a positive PCR test for SARS-CoV-2 or hospitalization for COVID-19-related respiratory tract disease
≥14 days after initially booked study visit date until 6 months after initially booked study visit date

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
COVID-19-related hospitalization
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
COVID-19-related respiratory tract disease hospitalization
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
COVID-19-related cardio-respiratory disease hospitalization
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
All-cause respiratory tract disease hospitalization
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
All-cause cardio-respiratory hospitalization
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
All-cause lower respiratory tract disease hospitalization
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
All-cause hospitalization
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
COVID-19 death
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
All-cause death
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Time Frame
COVID-19-related hospitalization (alternate definition)
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Laboratory-confirmed COVID-19
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Total length of hospital stays due to COVID-19-related respiratory tract disease
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Composite of hospitalization for COVID-19 or pneumonia (ICD-10 codes only)
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Hospitalization for any cardiovascular disease
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Hospitalization due to any infectious disease
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Hospitalization requiring mechanical ventilation
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
In-hospital mortality
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Cardio-respiratory mortality
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Respiratory mortality
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Cardiovascular mortality
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Intensive care unit admission
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Laboratory-confirmed COVID-19 hospitalization
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date
Any hospital contact associated with laboratory-confirmed COVID-19
Time Frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date
≥14 days after initially booked study visit date until 6 months after initially booked study visit date

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Tor Biering-Sørensen

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
ModernaTX, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Tor Biering-Sørensen, MD, MSc, MPH, PhD, Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 11, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 28, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 11, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 12, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 13, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • DAN-COVID
  • 2025-523841-82-00 (Other Identifier: EU Clinical Trial Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

In this trial, baseline and endpoint data will be collected from Danish administrative health registries, which are subject to Danish legislation and can only be made available to a third party under certain conditions. Please contact the sponsor-investigator in case of any inquiries.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings