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Active, Not Recruiting

NCT Number: NCT07279766

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.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

COVID-19 Coronaviridae Infections Coronavirus Infections Infections Lung Diseases Nidovirales Infections Pneumonia Pneumonia, Viral RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

50 year–64 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark

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About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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:
  • Asthma
  • Cancer (excluding non-melanoma skin cancer)
  • Cardiomyopathies
  • Cerebrovascular disease
  • Chronic kidney disease
  • Chronic lung disease
  • Cystic Fibrosis
  • Dementia
  • Diabetes
  • Down syndrome
  • Heart failure
  • Human Immunodeficiency Virus
  • Immunosuppressive therapy
  • Ischemic heart disease
  • Liver disease
  • Neurological/neuromuscular disease
  • Psychiatric disease (psychotic, schizophrenic, schizotypal, depressive, and bipolar (affective) disorders).
  • Severe obesity (body mass index >35 kg/m2)
  • Severe substance abuse
  • Short bowel syndrome
  • Solid organ transplant or hematological transplant
  • Apart from these, there are no specific exclusion criteria for this study

Treatment and study plan

mRNA-1273 (Moderna COVID-19 vaccine)

Biological

For this arm, the current variant formulation of Spikevax (mRNA-1273) vaccine will be used.

Primary outcomes

  1. 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

Secondary outcomes

  1. COVID-19-related hospitalization

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  2. 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

  3. 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

  4. 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

  5. All-cause cardio-respiratory hospitalization

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  6. 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

  7. All-cause hospitalization

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  8. COVID-19 death

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  9. All-cause death

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

Other outcomes

  1. 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

  2. Laboratory-confirmed COVID-19

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  3. 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

  4. 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

  5. Hospitalization for any cardiovascular disease

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  6. 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

  7. Hospitalization requiring mechanical ventilation

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  8. In-hospital mortality

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  9. Cardio-respiratory mortality

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  10. Respiratory mortality

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  11. Cardiovascular mortality

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  12. Intensive care unit admission

    Time frame: ≥14 days after initially booked study visit date until 6 months after initially booked study visit date

  13. 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. 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

Sponsors and collaborators

Lead sponsor

Tor Biering-Sørensen

Other

Collaborators

  • ModernaTX, Inc.

Registry information

Official study title

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

Acronym: DAN-COVID

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Dec 12, 2025
Registry last updated
Mar 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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