Study of mRNA Vaccine Formulation Against COVID-19 in Healthy Adults 18 Years of Age and Older

Study at a glance

From the registry record, last updated by the sponsor on 11 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title

Immunogenicity and Safety of the First-in-Human SARS-CoV-2 mRNA Vaccine Formulation in Healthy Adults 18 Years of Age and Older

ClinicalTrials.gov ID

NCT04798027

Acronym / sponsor ID

VAW00001 / VAW00001

Conditions

COVID-19

Phase

Phase 1/2

Study type

Interventional

Recruitment status

TerminatedReason stopped: Sponsor's decision not to pursue further development of this product given the wide availability of authorized/approved mRNA COVID-19 vaccines

Enrolment

182 participants (actual)

Lead sponsor

Sanofi Pasteur, a Sanofi CompanyIndustry (pharma, biotech, devices)

Study start

12 Mar 2021 (actual)

Primary completion

27 Jun 2022 (actual)

Study completion

27 Jun 2022 (actual)

First posted

15 Mar 2021 (actual)

Results

Posted 15 Dec 2023

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose

Prevention

Allocation

Randomised

Intervention model

Parallel groups

Masking

Quadruple blind (participant, care provider, investigator, outcomes assessor)

Number of arms

9

Model description

This was a sequential group prevention study consisting of a sentinel cohort followed by the Full Enrollment Cohort. There were 3 dose levels (up to 25 participants 18-49 years of age for each dose level) in the Sentinel Cohort, which were done in an open-label fashion with stepwise safety evaluation for each dose level and each vaccination. All sentinel participants received 2 vaccinations, 21 days apart. For the Full Enrollment Cohort (FEC), which was done in a double-blind design participants were stratified into 2 groups based on age at enrollment: the younger adult age group (140 planned participants 18-49 years of age) and the older adult age group (168 planned participants greater than or equal to [>=] 50 years of age). The FEC Cohort 1 (Groups 1 to 3) received a single injection of study intervention while participants in Cohort 2 (Groups 4 to 6) received 2 vaccinations (to be given 21 days apart).

Who may qualify

Ages

18 years and older

Sex

All

Healthy volunteers

Accepted

Age groups

Adult, Older adult

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Primary outcome

1. Number of Participants Reporting Immediate Unsolicited Adverse Events (AEs)

   Time frame: Within 30 minutes post any and each vaccination (Vaccination 1 [i.e., at Day 1] and 2 [i.e., at Day 22])

   AE: any untoward medical occurrence in clinical investigation participant administered medicinal product \& which did not have any causal relationship with the treatment. Unsolicited AE: observed AE that did not fulfill conditions prelisted in case report form (CRF) in terms of diagnosis \&/or onset window post-vaccination. All participants were observed for 30 minutes after vaccination, \& any unsolicited AEs occurred during that time were recorded as immediate unsolicited AEs in CRF. Reported AEs were presented as pre-specified in protocol. In the data table, '0' in number analyzed field denotes that no participants were available for assessment for specified Group as no one in that group received vaccination 2.

2. Number of Participants With Solicited Injection Site Reactions

   Time frame: Within 7 days after any and each vaccination (Vaccination 1 [i.e., at Day 1] and 2 [i.e., at Day 22])

   Solicited reaction (SR): expected adverse reaction (sign or symptom) observed \& reported under conditions (nature \& onset) prelisted (i.e., solicited) in CRF and considered as related to product administered. Solicited injection site reactions included pain, erythema, \& swelling. Reported AEs for each arm were presented as pre-specified in study protocol. In the data table, '0' in number analyzed field denotes that no participants were available for assessment for specified Group as no one in that group received vaccination 2.

3. Number of Participants With Solicited Systemic Reactions

   Time frame: Within 7 days after any and each vaccination (Vaccination 1 [i.e., at Day 1] and 2 [i.e., at Day 22])

   SR was an expected adverse reaction (sign or symptom) observed \& reported under conditions (nature \& onset) prelisted (i.e., solicited) in CRF \& considered as related to product administered. Solicited systemic reactions included fever, headache, malaise, myalgia, arthralgia \& chills. Reported AEs for each arm were presented as pre-specified in study protocol. In the data table, '0' in number analyzed field denotes that no participants were available for assessment for specified Group as no one in that group received vaccination 2.

4. Number of Participants With Unsolicited Adverse Events

   Time frame: Within 21 days after any and each vaccination (Vaccination 1 [i.e., at Day 1] and 2 [i.e., at Day 22])

   An AE was any untoward medical occurrence in a clinical investigation participant administered a medicinal product and which did not have any casual relationship with the treatment. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the CRF in terms of diagnosis and/or onset window post-vaccination. Reported AEs for each arm were presented as pre-specified in the study protocol. In the data table, '0' in number analyzed field denotes that no participants were available for assessment for specified Group as no one in that group received vaccination 2.

5. Number of Participants Reporting Serious Adverse Events (SAEs), Adverse Event of Special Interest (AESIs) and Medically Attended Adverse Events (MAAEs)

   Time frame: From Day 1 until 12 months post last vaccination (i.e., up to Day 366 for Cohort 1 groups and up to Day 387 for Cohort 2 groups)

   SAEs: any untoward medical occurrence that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. AESIs: event for which ongoing monitoring \& rapid communication by investigator to the sponsor was done. MAAE was a new onset or worsening of a condition that prompted participant or participant's parent/legally acceptable representative to seek unplanned medical advice at physician's office or emergency department. Reported AEs for each arm were presented as pre-specified in study protocol.

6. Number of Participants With Laboratory Test Results Based on US Food and Drug Administration (FDA) Toxicity Grading Guidance

   Time frame: From Day 1 up to up to 8 days post last vaccination (i.e., up to Day 9 for Cohort 1 groups; up to Day 30 for Cohort 2 groups)

   Laboratory tests: hemoglobin (male \& female), above \& below normal white blood cell, lymphocytes, neutrophils \& eosinophils, platelet count, creatinine \& blood urea nitrogen, hyponatremia \& hypernatremia, hyperkalemia \& hypokalemia, hyperglycemia (non-fasting), hypoproteinemia, alkaline phosphate, alanine aminotransferase, aspartate aminotransferase, bilirubin (with any increase in liver function test [LFT], bilirubin (normal LFT), prothrombin \& partial thromboplastin time (seconds), Urine: protein, glucose \& blood. US FDA "Toxicity Grading Scale for Healthy Adults \& Adolescent Volunteers" was used for grading; Grade 1=mild, Grade 2=moderate \& Grade 3=severe. In the data table, 'number analyzed'=participants with available data for each specified category \& '0'=none of participants were available for assessment for specified Group.

7. Geometric Mean Titers (GMTs) of Neutralizing Antibodies Against SARS-CoV-2 Recombinant Protein Vaccine at Day 1

   Time frame: Day 1 (pre-vaccination)

   GMTs of SARS-CoV-2 neutralizing antibodies (D614G variant) was measured using a neutralization assay. Titers were expressed in terms of 1/dilution. Data for this OM was planned to be collected and analyzed for combined population (FEC+ Sentinel Cohort) in which same dose-level groups in Sentinel Cohort and FEC were pooled for analysis.

8. Geometric Mean Titers (GMTs) of Neutralizing Antibodies Against SARS-CoV-2 Recombinant Protein Vaccine at Day 22

   Time frame: Day 22 (post-vaccination)

   GMTs of SARS-CoV-2 neutralizing antibodies (D614G variant) was measured using a neutralization assay. Titers were expressed in terms of 1/dilution.

9. Geometric Mean Titers (GMTs) of Neutralizing Antibodies Against SARS-CoV-2 Recombinant Protein Vaccine at Day 36

   Time frame: Day 36 (post-vaccination)

   GMTs of SARS-CoV-2 neutralizing antibodies (D614G variant) was measured using a neutralization assay. Titers were expressed in terms of 1/dilution.

10. Geometric Mean Fold-rise (GMFR) of Serum Neutralization Antibody Titers at Day 22

    Time frame: Day 1 (pre-vaccination) and Day 22 (post-vaccination)

    SARS-CoV-2 neutralizing antibodies (D614G variant) was measured using a neutralization assay. Fold-rise was calculated as the ratio of titer values of neutralizing antibodies post-vaccination (Day 22) and pre-vaccination (on Day 1) i.e., Day 22/Day 1.

11. Geometric Mean Fold-rise of Serum Neutralization Antibody Titers at Day 36

    Time frame: Day 1 (pre-vaccination) and Day 36 (post-vaccination)

    SARS-CoV-2 neutralizing antibodies (D614G variant) was measured using a neutralization assay. Fold-rise was calculated as the ratio of titer values of neutralizing antibodies post-vaccination (Day 36) and pre-vaccination (on Day 1) i.e., Day 36/Day 1.

12. Percentage of Participants With >=2-fold and >=4-fold Rise in Serum Neutralization Antibody Titers at Day 22

    Time frame: Day 1 (pre-vaccination) and Day 22 (post-vaccination)

    SARS-CoV-2 neutralizing antibodies (D614G variant) was measured using a neutralization assay. The fold rise (2-fold and 4-fold) was calculated as the ratio of titer values of neutralizing antibodies post-vaccination (on Day 22) and pre-vaccination (on Day 1) i.e., Day 22/Day 1.

13. Percentage of Participants With >=2-Fold and >=4-Fold Rise in Serum Neutralization Antibody Titer at Day 36

    Time frame: Day 1 (pre-vaccination) and Day 36 (post-vaccination)

    SARS-CoV-2 neutralizing antibodies (D614G variant) was measured using a neutralization assay. The fold rise (2-fold and 4-fold) was calculated as the ratio of titer values of neutralizing antibodies post-vaccination (on Day 36) and pre-vaccination (on Day 1) i.e., Day 36/Day 1.

14. Percentage of Participants Achieving Seroconversion Against SARS-CoV-2 Virus Antigens at Day 22

    Time frame: Day 22 (post-vaccination)

    Seroconversion was defined as participants with a Baseline (Day 1) titer values below lower limit of quantification (LLOQ) with a detectable neutralization antibody titer above assay LLOQ post injection (at Day 22). LLOQ of the neutralization assay was a titer of 10.

15. Percentage of Participants Achieving Seroconversion Against SARS-CoV-2 Virus Antigens at Day 36

    Time frame: Day 36 (post-vaccination)

    Seroconversion was defined as participants with a Baseline (Day 1) titer values below LLOQ with a detectable neutralization antibody titer above assay LLOQ post injection (at Day 36). LLOQ of the neutralization assay was a titer of 10.

Results and safety

Loading the posted results from ClinicalTrials.gov…

Research links

• Official record on ClinicalTrials.govLast updated by the sponsor 11 Sep 2025.
• Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
• VAW00001 Plain Language Results SummaryLink provided by the sponsor.
• Individual participant dataSharing planned: Yes. Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

21 sites in 4 countries: see every site and its status.