NCT05972993

A Safety and Immune Response Study to Evaluate Varying Doses of an mRNA Vaccine Against Coronavirus Disease 2019 (COVID-19) in Healthy Adults

Completed Phase 1 Results posted Last updated 28 May 2025

What this trial tests

Phase 1 trial testing mRNA-CR-04 vaccine 10μg in COVID-19 in 114 participants. Completed in 14 October 2024.

Timeline

7 August 2023

Primary endpoint
9 May 2024

14 October 2024

Quick facts

Lead sponsor	GlaxoSmithKline
Phase	Phase 1
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	sequential
Masking	triple
Primary purpose	prevention
Enrollment	114
Start date	7 August 2023
Primary completion	9 May 2024
Estimated completion	14 October 2024
Sites	4 locations across United States

Drugs / interventions tested

• mRNA-CR-04 vaccine 10μg — full drug profile →
• mRNA-CR-04 vaccine 30μg — full drug profile →
• mRNA-CR-04 vaccine 100μg — full drug profile →
• Placebo
• mRNA-CR-04 vaccine 3μg — full drug profile →

Conditions studied

• COVID-19 — all drugs for COVID-19 →

Sponsor

GlaxoSmithKline — full company profile →

Who can join

Adults 18 to 49, any sex, with COVID-19. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Number of Participants With Any Solicited Administration Site Events Primary · Day 1 to Day 7

The solicited administration site events are pain, redness, swelling and lymphadenopathy (axillary swelling/ tenderness on the same side of the body as the site of injection). Any = occurrence of the event regardless of intensity grade.

Pain at administration site

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	8
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	10
Part A, Group 2: Placebo	1
Part A, Group 3: mRNA CR-04 100 µg	15
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	9
Part B: mRNA CR-04 10 µg	6
Part B: Placebo	1

Redness at administration site

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	4
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Swelling at administration site

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	1
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	3
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Lymphadenopathy

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	2
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	2
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	2
Part B: mRNA CR-04 10 µg	3
Part B: Placebo	0

Number of Participants With Any Solicited Systemic Events Primary · Day 1 to Day 7

The solicited systemic events are fever, headache, myalgia (muscle pain), arthralgia (joint pain), fatigue (tiredness), chills, abdominal pain, vomiting and diarrhea. Fever is defined as body temperature ≥38ºC; preferred location for measuring the temperature is oral. Any = occurrence of the event regardless of intensity grade.

Fever

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	3
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Headache

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	5
Part A, Group 1: Placebo	1
Part A, Group 2: mRNA CR-04 30 µg	4
Part A, Group 2: Placebo	1
Part A, Group 3: mRNA CR-04 100 µg	8
Part A, Group 3: Placebo	2
Part B: mRNA CR-04 3 µg	6
Part B: mRNA CR-04 10 µg	4
Part B: Placebo	2

Myalgia

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	4
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	4
Part A, Group 2: Placebo	2
Part A, Group 3: mRNA CR-04 100 µg	11
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	6
Part B: mRNA CR-04 10 µg	8
Part B: Placebo	0

Arthralgia

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	1
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	3
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	2
Part A, Group 3: Placebo	1
Part B: mRNA CR-04 3 µg	1
Part B: mRNA CR-04 10 µg	2
Part B: Placebo	0

Fatigue

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	8
Part A, Group 1: Placebo	1
Part A, Group 2: mRNA CR-04 30 µg	7
Part A, Group 2: Placebo	1
Part A, Group 3: mRNA CR-04 100 µg	8
Part A, Group 3: Placebo	2
Part B: mRNA CR-04 3 µg	7
Part B: mRNA CR-04 10 µg	5
Part B: Placebo	1

Chills

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	2
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	3
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	3
Part A, Group 3: Placebo	1
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	2
Part B: Placebo	1

Abdominal Pain

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	1
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	1
Part A, Group 3: Placebo	1
Part B: mRNA CR-04 3 µg	1
Part B: mRNA CR-04 10 µg	1
Part B: Placebo	0

Vomiting

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	1
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	2
Part B: Placebo	0

Number of Participants With Any Unsolicited Adverse Events (AEs) Primary · Day 1 to Day 30

An unsolicited AE is an AE that is either not included in the list of solicited events or can be included in the list of solicited events but with an onset outside the specified period of follow-up for solicited events. Unsolicited AEs include both serious and nonserious AEs. Any = occurrence of the event regardless of intensity grade.

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	6
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	5
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	4
Part A, Group 3: Placebo	3
Part B: mRNA CR-04 3 µg	8
Part B: mRNA CR-04 10 µg	2
Part B: Placebo	1

Number of Participants With Any Hematological and Biochemical Laboratory Abnormalities Primary · Day 1 to Day 15

The hematological and biochemical parameters included alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), total bilirubin, creatinine, direct bilirubin, basophils, eosinophils increase, erytrocytes, hemoglobin decrease, lymphocytes decrease, mean corpuscular hemoglobin, mean corpuscular volume, monocytes, neutrophils decrease, platelets decrease, white blood cells (WBC) increase. Below = value below the laboratory reference range defined for the specified visit and laboratory parameter; Within = value within the laboratory reference range defined for t

ALT

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	2
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	1
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	1
Part A, Group 1: mRNA CR-04 10 µg	2
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	1
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	2
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	1
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	1
Part A, Group 2: Placebo	1
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	1
Part B: Placebo	0

ALP

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	1
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	1
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

AST

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Total Bilirubin

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Creatinine

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Direct Bilirubin

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Basophils

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Eosinophils Increase

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Number of Participants With Any Medically Attended Adverse Events (MAAEs) Primary · Day 1 to Day 31

A MAAE is an AE for which the participant received medical attention including any symptom or illness requiring hospitalization, or an emergency room visit, or visit to/by a healthcare professional. Any = occurrence of the event regardless of intensity grade.

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	1
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	2
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	2
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Number of Participants With Any Serious Adverse Events (SAEs) Primary · Day 1 to Day 31

An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, abnormal pregnancy outcome or any other situation as determined by the investigator. Any = occurrence of the event regardless of intensity grade.

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	1
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Number of Participants With Any Adverse Events of Special Interest (AESIs) Primary · Day 1 to Day 31

AESIs include potential immune-mediated diseases (pIMDs) which are autoimmune diseases and other inflammatory and/or neurologic disorders of interest which may or may not have an autoimmune etiology, myocarditis, and pericarditis, virologically confirmed COVID-19 cases, anaphylaxis, or severe hypersensitivity within 24 hours after study investigational product administration. Any = occurrence of the event regardless of intensity grade.

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Number of Participants With Any MAAEs Secondary · Throughout the study period (Day 1 to Month 6)

A MAAE is an AE for which the participant received medical attention including any symptom or illness requiring hospitalization, or an emergency room visit, or visit to/by a healthcare professional. Any = occurrence of the event regardless of intensity grade.

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	3
Part A, Group 1: Placebo	1
Part A, Group 2: mRNA CR-04 30 µg	2
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	3
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	3
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Number of Participants With Any SAEs Secondary · Throughout the study period (Day 1 to Month 6)

An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, abnormal pregnancy outcome or any other situation as determined by the investigator. Any = occurrence of the event regardless of intensity grade.

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	1
Part A, Group 1: Placebo	0
Part A, Group 2: mRNA CR-04 30 µg	1
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	0
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Number of Participants With Any AESIs Secondary · Throughout the study period (Day 1 to Month 6)

AESIs include potential immune-mediated diseases (pIMDs) which are autoimmune diseases and other inflammatory and/or neurologic disorders of interest which may or may not have an autoimmune etiology, myocarditis, and pericarditis, virologically confirmed COVID-19 cases, anaphylaxis, or severe hypersensitivity within 24 hours after study investigational product administration. Any = occurrence of the event regardless of intensity grade.

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	0
Part A, Group 1: Placebo	1
Part A, Group 2: mRNA CR-04 30 µg	0
Part A, Group 2: Placebo	0
Part A, Group 3: mRNA CR-04 100 µg	1
Part A, Group 3: Placebo	0
Part B: mRNA CR-04 3 µg	0
Part B: mRNA CR-04 10 µg	0
Part B: Placebo	0

Geometric Mean Titers (GMT) of Neutralizing Titers Against Pseudovirus Bearing S Protein From Vaccine Encoded SARS-CoV-2 and Wild Type (WT) Strains Secondary · At Days 1, 15 and 31, and at Month 6

The analyzed neutralizing titers were SARS-CoV-2 Neutralizing Titer BA.5 and SARS-CoV-2 Neutralizing Titer D614G. D= Day; M= Month.

BA.5, D1

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	550.72	325.81 – 930.89
Part A, Group 2: mRNA CR-04 30 µg	526.95	325.54 – 852.97
Part A, Group 3: mRNA CR-04 100 µg	504.01	287.71 – 882.94
Part A: Placebo Combined	320.87	154.81 – 665.05
Part B: mRNA CR-04 3 µg	689.36	402.31 – 1181.24
Part B: mRNA CR-04 10 µg	574.02	385.58 – 854.56
Part B: Placebo	493.05	92.19 – 2636.84

BA.5, D15

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	4271.90	2751.76 – 6631.81
Part A, Group 2: mRNA CR-04 30 µg	4720.61	3082.55 – 7229.14
Part A, Group 3: mRNA CR-04 100 µg	4795.20	3132.57 – 7340.29
Part A: Placebo Combined	453.93	298.47 – 690.36
Part B: mRNA CR-04 3 µg	2423.54	1796.47 – 3269.50
Part B: mRNA CR-04 10 µg	3596.47	2644.67 – 4890.81
Part B: Placebo	589.81	334.04 – 1041.42

BA.5, D31

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	4197.66	2747.44 – 6413.36
Part A, Group 2: mRNA CR-04 30 µg	3607.13	2463.89 – 5280.84
Part A, Group 3: mRNA CR-04 100 µg	6591.72	4448.81 – 9766.85
Part A: Placebo Combined	420.37	288.08 – 613.40
Part B: mRNA CR-04 3 µg	2157.80	1472.28 – 3162.53
Part B: mRNA CR-04 10 µg	2847.07	1944.62 – 4168.31
Part B: Placebo	602.35	297.53 – 1219.45

BA.5, M6

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	1414.22	786.90 – 2541.66
Part A, Group 2: mRNA CR-04 30 µg	1354.49	793.70 – 2311.51
Part A, Group 3: mRNA CR-04 100 µg	1919.56	1164.60 – 3163.94
Part A: Placebo Combined	444.43	266.94 – 739.93
Part B: mRNA CR-04 3 µg	1547.09	1100.15 – 2175.61
Part B: mRNA CR-04 10 µg	1677.07	1103.28 – 2549.28
Part B: Placebo	540.16	281.43 – 1036.75

D614G, D1

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	2502.06	1839.63 – 3403.03
Part A, Group 2: mRNA CR-04 30 µg	1409.21	931.99 – 2130.80
Part A, Group 3: mRNA CR-04 100 µg	1820.75	1080.88 – 3067.05
Part A: Placebo Combined	1421.87	706.04 – 2863.44
Part B: mRNA CR-04 3 µg	2139.66	1353.70 – 3381.96
Part B: mRNA CR-04 10 µg	1604.51	1013.28 – 2540.73
Part B: Placebo	1702.33	571.67 – 5069.18

D614G, D15

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	8073.12	5651.68 – 11532.03
Part A, Group 2: mRNA CR-04 30 µg	9990.27	7096.52 – 14064.02
Part A, Group 3: mRNA CR-04 100 µg	14543.96	10348.31 – 20440.70
Part A: Placebo Combined	1654.35	1186.60 – 2306.48
Part B: mRNA CR-04 3 µg	4661.13	3673.40 – 5914.45
Part B: mRNA CR-04 10 µg	6363.85	4982.55 – 8128.08
Part B: Placebo	2129.10	1358.56 – 3336.68

D614G, D31

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	6251.22	4450.68 – 8780.17
Part A, Group 2: mRNA CR-04 30 µg	7726.20	5712.62 – 10449.51
Part A, Group 3: mRNA CR-04 100 µg	12351.27	9068.09 – 16823.16
Part A: Placebo Combined	1585.37	1182.26 – 2125.92
Part B: mRNA CR-04 3 µg	4633.14	3382.40 – 6346.37
Part B: mRNA CR-04 10 µg	7601.57	5553.99 – 10404.02
Part B: Placebo	2819.98	1583.73 – 5021.26

D614G, M6

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	3813.02	2511.62 – 5788.74
Part A, Group 2: mRNA CR-04 30 µg	3970.88	2713.92 – 5810.01
Part A, Group 3: mRNA CR-04 100 µg	4645.04	3267.21 – 6603.92
Part A: Placebo Combined	2441.97	1715.51 – 3476.06
Part B: mRNA CR-04 3 µg	4059.06	3244.67 – 5077.85
Part B: mRNA CR-04 10 µg	3342.96	2541.75 – 4396.73
Part B: Placebo	2571.87	1680.53 – 3935.97

Geometric Mean Ratio (GMR) of Neutralizing Titers Against Pseudovirus Bearing S Protein From Vaccine Encoded SARS-CoV-2 and WT Strains Secondary · At Days 15 and 31, and at Month 6 (compared with baseline [Day 1])

The analyzed neutralizing titers were SARS-CoV-2 Neutralizing Titer BA.5 and SARS-CoV-2 Neutralizing Titer D614G. D= Day; M= Month.

BA.5, D15

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	9.25	5.96 – 14.36
Part A, Group 2: mRNA CR-04 30 µg	10.22	6.68 – 15.66
Part A, Group 3: mRNA CR-04 100 µg	10.38	6.78 – 15.90
Part A: Placebo Combined	0.98	0.65 – 1.50
Part B: mRNA CR-04 3 µg	3.91	2.90 – 5.27
Part B: mRNA CR-04 10 µg	5.80	4.27 – 7.89
Part B: Placebo	0.95	0.54 – 1.68

BA.5, D31

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	8.57	5.61 – 13.10
Part A, Group 2: mRNA CR-04 30 µg	7.37	5.03 – 10.78
Part A, Group 3: mRNA CR-04 100 µg	13.46	9.08 – 19.94
Part A: Placebo Combined	0.86	0.59 – 1.25
Part B: mRNA CR-04 3 µg	3.43	2.34 – 5.03
Part B: mRNA CR-04 10 µg	4.53	3.09 – 6.63
Part B: Placebo	0.96	0.47 – 1.94

BA.5, M6

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	2.76	1.53 – 4.95
Part A, Group 2: mRNA CR-04 30 µg	2.64	1.55 – 4.51
Part A, Group 3: mRNA CR-04 100 µg	3.74	2.27 – 6.17
Part A: Placebo Combined	0.87	0.52 – 1.44
Part B: mRNA CR-04 3 µg	2.26	1.61 – 3.17
Part B: mRNA CR-04 10 µg	2.45	1.61 – 3.72
Part B: Placebo	0.79	0.41 – 1.51

D614G, D15

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	4.68	3.28 – 6.69
Part A, Group 2: mRNA CR-04 30 µg	5.80	4.12 – 8.16
Part A, Group 3: mRNA CR-04 100 µg	8.44	6.00 – 11.86
Part A: Placebo Combined	0.96	0.69 – 1.34
Part B: mRNA CR-04 3 µg	2.53	1.99 – 3.21
Part B: mRNA CR-04 10 µg	3.45	2.70 – 4.41
Part B: Placebo	1.15	0.74 – 1.81

D614G, D31

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	3.50	2.49 – 4.91
Part A, Group 2: mRNA CR-04 30 µg	4.32	3.20 – 5.85
Part A, Group 3: mRNA CR-04 100 µg	6.91	5.07 – 9.41
Part A: Placebo Combined	0.89	0.66 – 1.19
Part B: mRNA CR-04 3 µg	2.43	1.77 – 3.32
Part B: mRNA CR-04 10 µg	3.98	2.91 – 5.45
Part B: Placebo	1.48	0.83 – 2.63

D614G, M6

Group	Value	95% CI
Part A, Group 1: mRNA CR-04 10 µg	1.99	1.31 – 3.03
Part A, Group 2: mRNA CR-04 30 µg	2.08	1.42 – 3.04
Part A, Group 3: mRNA CR-04 100 µg	2.43	1.71 – 3.45
Part A: Placebo Combined	1.28	0.90 – 1.82
Part B: mRNA CR-04 3 µg	2.01	1.61 – 2.51
Part B: mRNA CR-04 10 µg	1.65	1.26 – 2.18
Part B: Placebo	1.27	0.83 – 1.95

Adverse events — posted to ClinicalTrials.gov

Time frame: Solicited AEs: Day 1 to Day 7; Unsolicited AEs: Day 1 to Day 30. SAEs, MAAEs, AESIs: Day 1 up to study end (6 months post-investigational products administration).. Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Part A, Group 1: mRNA CR-04 10 µg

Serious: 1/18 (6%)

Deaths: 0/18

Part A, Group 1: Placebo

Serious: 0/6 (0%)

Deaths: 0/6

Part A, Group 2: mRNA CR-04 30 µg

Serious: 1/18 (6%)

Deaths: 0/18

Part A, Group 2: Placebo

Serious: 0/6 (0%)

Deaths: 0/6

Part A, Group 3: mRNA CR-04 100 µg

Serious: 0/18 (0%)

Deaths: 0/18

Part A, Group 3: Placebo

Serious: 0/6 (0%)

Deaths: 0/6

Part B: mRNA CR-04 3 µg

Serious: 0/18 (0%)

Deaths: 0/18

Part B: mRNA CR-04 10 µg

Serious: 0/18 (0%)

Deaths: 0/18

Part B: Placebo

Serious: 0/6 (0%)

Deaths: 0/6

Serious adverse events (4 terms)

Reaction	System	Part A, Group 1: mRNA CR-0…	Part A, Group 1: Placebo	Part A, Group 2: mRNA CR-0…	Part A, Group 2: Placebo	Part A, Group 3: mRNA CR-0…	Part A, Group 3: Placebo	Part B: mRNA CR-04 3 µg	Part B: mRNA CR-04 10 µg	Part B: Placebo
Otitis externa	Infections and infestations	—	—	—	—	—	—	—	—	—
Otitis media	Infections and infestations	—	—	—	—	—	—	—	—	—
Ankle fracture	Injury, poisoning and procedural complications	—	—	—	—	—	—	—	—	—
Suicide attempt	Psychiatric disorders	—	—	—	—	—	—	—	—	—

Other adverse events (59 terms — click to expand)

Reaction	System	Part A, Group 1: mRNA CR-0…	Part A, Group 1: Placebo	Part A, Group 2: mRNA CR-0…	Part A, Group 2: Placebo	Part A, Group 3: mRNA CR-0…	Part A, Group 3: Placebo	Part B: mRNA CR-04 3 µg	Part B: mRNA CR-04 10 µg	Part B: Placebo
Injection site pain	General disorders	—	—	—	—	—	—	—	—	—
Myalgia	Musculoskeletal and connective tissue disorders	—	—	—	—	—	—	—	—	—
Fatigue	General disorders	—	—	—	—	—	—	—	—	—
Headache	Nervous system disorders	—	—	—	—	—	—	—	—	—
Injection site erythema	General disorders	—	—	—	—	—	—	—	—	—
Lymphadenopathy	Blood and lymphatic system disorders	—	—	—	—	—	—	—	—	—
Chills	General disorders	—	—	—	—	—	—	—	—	—
Injection site induration	General disorders	—	—	—	—	—	—	—	—	—
Pyrexia	General disorders	—	—	—	—	—	—	—	—	—
Prothrombin time prolonged	Investigations	—	—	—	—	—	—	—	—	—
Arthralgia	Musculoskeletal and connective tissue disorders	—	—	—	—	—	—	—	—	—
Diarrhoea	Gastrointestinal disorders	—	—	—	—	—	—	—	—	—
Vomiting	Gastrointestinal disorders	—	—	—	—	—	—	—	—	—
COVID-19	Infections and infestations	—	—	—	—	—	—	—	—	—
SARS-CoV-2 antibody test positive	Investigations	—	—	—	—	—	—	—	—	—
Palpitations	Cardiac disorders	—	—	—	—	—	—	—	—	—
Thyroid mass	Endocrine disorders	—	—	—	—	—	—	—	—	—
Diplopia	Eye disorders	—	—	—	—	—	—	—	—	—
Abdominal pain	Gastrointestinal disorders	—	—	—	—	—	—	—	—	—
Dyspepsia	Gastrointestinal disorders	—	—	—	—	—	—	—	—	—
Gastrooesophageal reflux disease	Gastrointestinal disorders	—	—	—	—	—	—	—	—	—
Nausea	Gastrointestinal disorders	—	—	—	—	—	—	—	—	—
Toothache	Gastrointestinal disorders	—	—	—	—	—	—	—	—	—
Influenza like illness	General disorders	—	—	—	—	—	—	—	—	—
Injection site pruritus	General disorders	—	—	—	—	—	—	—	—	—
Malaise	General disorders	—	—	—	—	—	—	—	—	—
Non-cardiac chest pain	General disorders	—	—	—	—	—	—	—	—	—
Bronchitis	Infections and infestations	—	—	—	—	—	—	—	—	—
Gastroenteritis	Infections and infestations	—	—	—	—	—	—	—	—	—
Haemophilus infection	Infections and infestations	—	—	—	—	—	—	—	—	—
Nasopharyngitis	Infections and infestations	—	—	—	—	—	—	—	—	—
Pharyngitis streptococcal	Infections and infestations	—	—	—	—	—	—	—	—	—
Upper respiratory tract infection	Infections and infestations	—	—	—	—	—	—	—	—	—
Viral upper respiratory tract infection	Infections and infestations	—	—	—	—	—	—	—	—	—
Joint dislocation	Injury, poisoning and procedural complications	—	—	—	—	—	—	—	—	—
Procedural pain	Injury, poisoning and procedural complications	—	—	—	—	—	—	—	—	—
Blood pressure diastolic increased	Investigations	—	—	—	—	—	—	—	—	—
Blood pressure increased	Investigations	—	—	—	—	—	—	—	—	—
Blood pressure systolic increased	Investigations	—	—	—	—	—	—	—	—	—
Haemoglobin decreased	Investigations	—	—	—	—	—	—	—	—	—

Most-reported serious reactions: Otitis externa, Otitis media, Ankle fracture, Suicide attempt.

Data from ClinicalTrials.gov NCT05972993 adverse events section.

Sponsor's own description

The purpose of this study is to evaluate the safety, reactogenicity and immune responses of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA-CR-04 vaccine construct when administered in healthy adults previously vaccinated with SARS-CoV-2 mRNA vaccines.

Publications & conference data

1 peer-reviewed publication reference this trial (live from Europe PMC):

1. Phase 1 Randomized Controlled Trial of the Safety and Immunogenicity of the SARS-CoV-2 (Omicron BA.5) mRNA-CR-04 Vaccine in Adults 18-49 Years of Age.
   Naficy A, Venken M, Xi Y, Loughrey M, et al · · 2025 · PMID 41311913 · DOI 10.1093/ofid/ofaf689