A Phase 4 interventional study of mCombriax® (mRNA-1083) and Efluelda® (TIV-HD) and Spikevax® (mRNA-1273) in COVID-19 and Influenza, sponsored by Tor Biering-Sørensen. Not yet recruiting at 3 sites in 2 countries. Open to participants aged 65 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-27.
Sponsored by Tor Biering-Sørensen · Phase 4, Interventional, and Prevention
The purpose of this pragmatic randomized trials is to evaluate the comparative vaccine effectiveness (cVE) of mCombriax® (mRNA-1083) versus same day co-administration of the active comparators (i.e., high-dose influenza vaccine/Efluelda® and mRNA-1273/Spikevax®) among adults aged 65 years and older.
This Phase 4 randomized, active-comparator, pragmatic trial is designed to evaluate the effectiveness of a seasonal variant-containing formulation of mCombriax® (mRNA-1083) compared with same-day co-administration of authorized standalone enhanced influenza and COVID-19 vaccines in adults aged ≥65 years. The trial is designed to be conducted over two consecutive respiratory virus seasons to account for potential seasonal variation in virus circulation, vaccine composition, and effectiveness. The primary objective is to evaluate the comparative vaccine effectiveness (cVE) of the combination vaccine with respect to clinically relevant outcomes, including severe influenza and COVID-19. Demonstration of non-inferior protection in real-world setting, in combination with the potential programmatic advantages of a single-dose strategy, may support policy recommendations, reimbursement decisions, and broader implementation of combined seasonal respiratory vaccination strategies.
7,990 studies on the registry are indexed under COVID-19; 466 are open to participants now.
This study's planned enrollment of 410,000 is above the median of 102 across 4,364 interventional studies indexed under COVID-19.
Browse COVID-19 studies →Tor Biering-Sørensen is the lead sponsor of 22 studies on the registry; 11 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
An authorized mRNA-based multicomponent vaccine encoding antigens targeting both seasonal influenza and SARS-CoV-2 viruses.
Biological: mCombriax® (mRNA-1083)
Same-day co-administration of an authorized high-dose trivalent influenza vaccine (TIV-HD; Efluelda®) and an authorized COVID-19 mRNA vaccine (Spikevax®, mRNA-1273)
Biological: Efluelda® (TIV-HD) and Spikevax® (mRNA-1273)
An authorized mRNA-based multicomponent vaccine encoding antigens targeting both seasonal influenza and SARS-CoV-2 viruses.
Drug page: 2019-nCoV Vaccine mRNA-1273
Same-day co-administration of an authorized high-dose trivalent influenza vaccine (TIV-HD; Efluelda®) and an authorized COVID-19 mRNA vaccine (Spikevax®, mRNA-1273)
Medically attended influenza and/or COVID-19
Defined as a laboratory-confirmed positive influenza A/B test or positive SARS-CoV-2 test, regardless of healthcare setting, or influenza-related or COVID-19-related hospitalization, defined by ICD-10 codes.
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Influenza and/or COVID-19 hospitalization
Defined as hospitalization with a relevant ICD-10 code for influenza or COVID-19 infection or any hospitalization with a laboratory-confirmed positive influenza A/B test or SARS-CoV-2 test performed within 7 days prior to hospitalization or within 48 hours of hospital admission.
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Medically attended influenza
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Influenza hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Medically attended COVID-19
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
COVID-19 hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
All-cause cardio-respiratory hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
All-cause respiratory tract disease hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
All-cause hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Influenza-related cardio-respiratory hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
COVID-19-related cardio-respiratory hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Influenza-related respiratory tract disease hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
COVID-19-related respiratory tract disease hospitalization
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
All-cause death
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Influenza death
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
COVID-19 death
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Laboratory-confirmed influenza
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Laboratory-confirmed COVID-19
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Total length of hospital stays due to influenza-related respiratory tract disease
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Total length of hospital stays due to COVID-19-related respiratory tract disease
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Composite of hospitalization for COVID-19 or pneumonia
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Composite of hospitalization for influenza or pneumonia
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Composite of hospitalization for influenza or COVID-19 (ICD-10 codes only)
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Hospitalization for any cardiovascular disease
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Hospitalization due to any infectious disease
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Hospitalization requiring mechanical ventilation
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Intensive care unit admission
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
The burden and outcomes of influenza virus type and subtype (e.g., influenza A and B, including H1 and H3)
Time frame: From Day 14 after vaccination through the end of follow-up, up to 8 months after vaccination
Plan to share: Yes — 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.
Supporting information: Study protocol, Statistical analysis plan
No publications or documents are linked to this record.
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Tor Biering-Sørensen