Study of Recombinant Protein Vaccine Formulations 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 17 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title

Immunogenicity and Safety of SARS-CoV-2 Recombinant Protein Vaccine Formulations (With or Without Adjuvant) in Healthy Adults 18 Years of Age and Older

ClinicalTrials.gov ID

NCT04537208

Acronym / sponsor ID

VAT00001

Conditions

COVID-19 (Healthy Volunteers)

Phase

Phase 1/2

Study type

Interventional

Recruitment status

Completed

Enrolment

441 participants (actual)

Lead sponsor

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

Collaborators

GlaxoSmithKline

Study start

3 Sep 2020 (actual)

Primary completion

19 Nov 2021 (actual)

Study completion

19 Nov 2021 (actual)

First posted

3 Sep 2020 (actual)

Results

Posted 22 Jun 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

11

Model description

This was a parallel group prevention study. Participants from 2 age groups (adults 18 through 49 years of age and adults 50 years of age and older) received either 1 injection (Cohort 1) or 2 injections (Cohort 2) of study vaccine or placebo control. As a precautionary step, a sentinel safety cohort of 6 participants (younger adults only) within each dosing group from Cohort 1 was enrolled. An early safety data review was performed, including evaluation of safety data and laboratory measures to Day 9. Upon acceptable safety demonstrated from unblinded data review by limited members of the Sponsor Study Team, the remaining participants were enrolled simultaneously.

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

   Time frame: Day 1 (pre-vaccination)

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

2. Geometric Mean Titers of Neutralizing Antibodies Against SARS-CoV-2 Recombinant Protein Vaccine Formulations at Day 22

   Time frame: Day 22 (post-vaccination)

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

3. Geometric Mean Titers of Neutralizing Antibodies Against SARS-CoV-2 Recombinant Protein Vaccine Formulations at Day 36

   Time frame: Day 36 (post-vaccination)

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

4. 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 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.

5. 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 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.

6. Number 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 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.

7. Number 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 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.

8. 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 value below lower limit of quantification (LLOQ) with a detectable neutralization antibody titer above assay LLOQ post vaccination (at Day 22). LLOQ of the neutralization assay was a titer of 10.

9. 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 value below LLOQ with a detectable neutralization antibody titer above assay LLOQ post vaccination (at Day 36). LLOQ of the neutralization assay was a titer of 10.

10. Number of Participants With 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])

    An AE was defined as any untoward medical occurrence in a participant who received study vaccine and does not necessary had to have a causal relationship with treatment. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions prelisted in the case report form (CRF) in terms of diagnosis and/or onset window post-vaccination. All participants were observed for 30 minutes after vaccination, and any unsolicited systemic AEs occurred during that time were recorded as immediate unsolicited AEs in the CRF. Reported AEs for each arm were presented as pre-specified in the study protocol.

11. Number of Participants With Solicited Injection Site Reactions

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

    A solicited reaction (SR) was defined as an "expected" adverse reaction (AR) (sign or symptom) observed and reported under the conditions (nature and onset) prelisted (i.e., solicited) in the protocol and CRF and considered as related to vaccination. Solicited injection site reactions included pain, erythema and swelling. Reported AEs for each arm were presented as pre-specified in the study protocol.

12. Number of Participants With Solicited Systemic Reactions

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

    An SR was defined as an "expected" AR (sign or symptom) observed and reported under the conditions (nature and onset) prelisted (i.e., solicited) in the protocol and CRF and considered as related to vaccination. Solicited systemic reactions included fever, headache, malaise and myalgia. Reported AEs for each arm were presented as pre-specified in the study protocol.

13. Number of Participants With Unsolicited Adverse Events

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

    An AE was defined as any untoward medical occurrence in a participant who received study vaccine and does not necessary had to have a causal relationship with treatment. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions prelisted in the CRF in terms of diagnosis and/or onset post-vaccination. Reported AEs for each arm were presented as pre-specified in the study protocol.

14. Number of Participants With Medically Attended Adverse Events (MAAE)

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

    A MAAE were AEs with a new onset or a worsening of a condition that prompted the participant to seek unplanned medical advice at a physician's office (including phone contact or email) or emergency department. An AE was defined as any untoward medical occurrence in a participant who received study vaccine and does not necessarily had to have a causal relationship with treatment. Reported AEs for each arm were presented as pre-specified in the study protocol.

15. Number of Participants With Serious Adverse Events (SAE)

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

    An SAE was 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. Reported AEs for each arm were presented as pre-specified in the study protocol.

16. Number of Participants With Adverse Events of Special Interest (AESIs)

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

    An AESI (serious or non-serious) was defined as one of scientific and medical concern specific to the Sponsor's product or program, for which ongoing monitoring and rapid communication by the Investigator to the Sponsor was appropriate. Reported AEs for each arm were presented as pre-specified in the study protocol.

17. Number of Participants With Laboratory Test Results Based on US FDA Toxicity Grading Guidance

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

    Laboratory tests included hemoglobin (male and female), above and below normal white blood cell, lymphocytes, neutrophils \& eosinophils, platelet count, creatinine and 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 in LFT), amylase \& lipase, Urine: protein, glucose \& blood. The US FDA Guidance for Industry "Toxicity Grading Scale for Healthy Adults and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials" was used for grading. As per the guidance, Grade 1 = mild, Grade 2 = moderate and Grade 3 = severe.

Results and safety

Loading the posted results from ClinicalTrials.gov…

Research links

• Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2025.
• Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
• Derived from this study: PubMed 35035955De Rosa SC, Cohen KW, Bonaparte M, Fu B, Garg S, Gerard C, Goepfert PA, Huang Y, Larocque D, McElrath MJ, Morris D, Van der Most R, de Bruyn G, Pagnon A. Whole-blood cytokine secretion assay as a high-throughput alternative for assessing the cell-mediated immunity profile after two doses of an adjuvanted SARS-CoV-2 recombinant protein vaccine candidate. Clin Transl Immunology. 2022 Jan 11;11(1):e1360. doi: 10.1002/cti2.1360. eCollection 2022.
• Derived from this study: PubMed 33887209Goepfert PA, Fu B, Chabanon AL, Bonaparte MI, Davis MG, Essink BJ, Frank I, Haney O, Janosczyk H, Keefer MC, Koutsoukos M, Kimmel MA, Masotti R, Savarino SJ, Schuerman L, Schwartz H, Sher LD, Smith J, Tavares-Da-Silva F, Gurunathan S, DiazGranados CA, de Bruyn G. Safety and immunogenicity of SARS-CoV-2 recombinant protein vaccine formulations in healthy adults: interim results of a randomised, placebo-controlled, phase 1-2, dose-ranging study. Lancet Infect Dis. 2021 Sep;21(9):1257-1270. doi: 10.1016/S1473-3099(21)00147-X. Epub 2021 Apr 19.
• VAT00001 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.

11 sites in 1 country: see every site and its status.