COV-COMPARE Immunogenicity of Vaccine VLA2001 Compared to AZD1222 (COV-COMPARE)
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ClinicalTrials.gov Identifier: NCT04864561 |
Recruitment Status :
Completed
First Posted : April 29, 2021
Last Update Posted : March 20, 2023
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Condition or disease | Intervention/treatment | Phase |
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SARS-CoV-2 Virus Infection | Biological: VLA2001 Biological: AZD1222 Biological: VLA2001 - adolescent part Biological: Placebo | Phase 3 |
Approximately 4000 Adult participants will be recruited in the study. About 3000 participants aged 30 years and above will be randomized in a 2:1 ratio to receive 2 intramuscular recommended doses of either VLA2001 (n=2000) or AZD1222 (n=1000). In addition, approximately 1000 subjects aged 18-29 years will participate in this study in a non-randomized, open-label fashion to receive VLA2001. The 2 doses of vaccination for both vaccines will be administered 28 days apart, on Days 1 and 29. All visits will be conducted at the clinical site on an outpatient basis.
All participants - except those who already received a licensed COVID-19 vaccine outside of the study - will be offered a booster dose with VLA2001 between Jan and Mar 2022 and will have a follow-up visit 14 days (Visit B2) and 6months after the booster dose.
Approximately 660 Adolescent participants were planned to be recruited and randomized in a 1:1 ratio to receive 2 intramuscular doses of either VLA2001 (n=330) or placebo (n=300). Participants in the placebo group will receive a 2-dose primary immunization with VLA2001 on Day 85 and the second vaccination 28 days later. For safety reasons, the first 16 adolescents will be enrolled in an open label, non-randomized manner (sentinel dosing).
Recruitment of adolescent participants has been stopped after recruitment of 6 randomized participants (3 randomized to VLA2001 and 3 participants randomized to placebo) due to the low recruitment rate. The study design ensures a safety follow-up of at least 6 months after the last VLA2001 vaccination/booster for all enrolled study participants
Participants will be provided with an electronic Diary (e-Diary) and will be trained to record specifically solicited systemic and local symptoms daily as well as any additional AEs during follow-up period after each of both vaccinations up to the next visit to the site until Day 43 visit has been completed.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 4034 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Triple (Participant, Investigator, Outcomes Assessor) |
Masking Description: | study participants aged 18-29 years at the time of enrolment are unblinded, study participant aged 12-18 and 30 years above at the time of enrolment are blinded (sentinel group is unblinded) until 28 days after vaccination on day 208, when all participants will be unblinded. |
Primary Purpose: | Prevention |
Official Title: | A Randomized, Observer-Blind, Controlled, Superiority Study To Compare The Immunogenicity Against COVID-19, Of VLA2001 Vaccine To AZD1222 Vaccine, In Adults Including a Randomized, Observer-blind, Placebo Controlled Part in Adolescents (≥12 to <18 Years) |
Actual Study Start Date : | April 26, 2021 |
Actual Primary Completion Date : | July 19, 2021 |
Actual Study Completion Date : | March 13, 2023 |

Arm | Intervention/treatment |
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Experimental: VLA2001
<30 years will receive VLA2001; participants aged ≥30 years will be randomised 2:1 to receive VLA2001 or AZD1222
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Biological: VLA2001
whole virus inactivated SARS-CoV-2 vaccine adjuvanted with cytosine phospho-guanine (CpG) 1018 in combination with aluminium hydroxide 2 vaccinations 28 days apart |
Active Comparator: AZD1222
<30 years will receive VLA2001; participants aged ≥30 years will be randomised 2:1 to receive VLA2001 or AZD1222
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Biological: AZD1222
2 vaccinations 28 days apart AZD1222 is a recombinant, replication-defective chimpanzee adenovirus expressing the SARS-CoV-2 S surface glycoprotein. |
Experimental: VLA2001 - adolescent part
≥12 to < 18 years will be randomized 1:1 to receive VLA2001 or Placebo
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Biological: VLA2001 - adolescent part
whole virus inactivated SARS-CoV-2 vaccine adjuvanted with cytosine phospho-guanine (CpG) 1018 in combination with aluminium hydroxid 2 vaccinations 28 days apart and with a booster vaccination on day 208. Placebo group will receive VLA2001 on day 208 and following second vaccination 28 days later. |
Placebo Comparator: Placebo
≥12 to < 18 years will be randomized 1:1 to receive VLA2001 or Placebo
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Biological: Placebo
2 vaccinations 28 days apart with placebo (PBS buffer based on Dulbecco's PBS media formulation without Calcium and Magnesium ) |
- Immune response measured after completion of a 2-dose immunization schedule, as determined by the geometric mean titer (GMT) ratio in adults and GMT in adolescents of SARS-CoV-2-specific neutralizing antibodies [ Time Frame: Day 43 ]
- Immune response measured after completion of a 2-dose immunization schedule, as determined by Seroconversion in adults and adolescents (definded as 4-fold increase from baseline) of SARS-CoV-2-specific neutralizing antibodies [ Time Frame: Day 43 ]
- Frequency and severity of any Adverse Events (AE) [ Time Frame: Up to Day 43 post-vaccination ]
- Proportion of adult participants with seroconversion [ Time Frame: on Day 8 (age 55+ only), Day 29, Day 71 and Day 208 ]Seroconversion is defined as >= 4-fold increase in SARS-CoV-2 neutralizing antibody titer against the Wuhan strain and IgG antibodies directed against the S-protein of the Wuhan strain between Day 1 and the defined post-vaccination timepoints
- Proportion of adolescent participants with Seroconversion [ Time Frame: on Day 43, Day 71/Day 85 and Day 127 ]
- Immune response in adults as determined geometric mean titer (GMT) of SARS-CoV-2-specific neutralising antibodies [ Time Frame: on Day 8 (age 55+ only), Day 29, Day 71 and Day 208 ]
- Immune response in adolescents as determined by the GMT of SARS-CoV-2-specific neutralising antibodies [ Time Frame: on Day 43, Day 71/Day 85 and Day 127 ]
- GMT ratio of SARS-CoV-2-specific neutralizing antibodies in the adolescent and adult population [ Time Frame: on Day 43 ]
- Immune response in adults determined by the GMT of IgG antibodies to SARS-CoV-2 S-protein [ Time Frame: on Day 8 (age 55+ only), Day 29, Day 43, Day 71 and Day 208 ]
- Immune response in adolescents determined by the GMT of IgG antibodies to SARS-CoV-2 S-protein [ Time Frame: on Day 43, Day 71/Day 85 and Day 127 ]
- GMT ratio of IgG antibodies to SARS-CoV-2 S-protein in the adolescent and adult population [ Time Frame: on Day 43 ]
- Assessment of T-cell responses from PBMCs on selected time points in a subset of participants after in vitro stimulation with SARS-CoV-2 antigens using e.g., ELISpot or intracellular cytokine staining [ Time Frame: Adult: Day 29, Day 43, Day 71 and Day 208, Adolescence: on Day 43, Day 71/Day 85 and Day 127 ]
- Frequency and severity of solicited injection site and systemic reactions [ Time Frame: until 7 days after each and any vaccination ]
- Frequency and severity of any AE [ Time Frame: through study completion, up to 13 or 16 months ]
- Frequency and severity of any unsolicited AE [ Time Frame: through study completion, up to 13 or 16 months ]
- Frequency and severity of any unsolicited vaccine-related AE [ Time Frame: through study completion, up to 13 or 16 months ]
- Frequency and severity of any serious adverse event (SAE) [ Time Frame: through study completion, up to 13 or 16 months ]
- Frequency and severity of any adverse event of special interest (AESI) [ Time Frame: through study completion, up to 13 or 16 months ]
- Geometric mean fold rise (GMFR) with regards to SARS-CoV-2-specific neutralizing antibodies [ Time Frame: from day of booster vaccination to 14 days after booster vaccination ]adult participants with single booster
- GMT of SARS-CoV-2-specific neutralizing antibodies as measured by MNA50 including formal non-inferiority testing on the GMT ratio [ Time Frame: on day of booster vaccination, 14 days and 6 months post booster ]adult participants with single booster
- Proportion of participants with 4-fold increase with regards to SARS-CoV-2-specific neutralizing antibodies [ Time Frame: from day of booster vaccination to 14 days after booster vaccination ]adult participants with single booster
- GMFR with regards to S-protein binding antibodies [ Time Frame: from day of booster vaccination to 14 days after booster vaccination ]adult participants with single booster
- Proportion of participants with 4-fold increase with regards to S-protein binding antibodies [ Time Frame: from day of booster vaccination to 14 days after booster vaccination ]adult participants with single booster
- Assessment of T-cell responses from PBMCs in a subset of participants after in vitro stimulation with SARS-CoV-2 antigens using ELISpot [ Time Frame: on day of booster vaccination, 14 days and 6 months post booster ]adult participants with single booster
- Frequency and severity of solicited injection site and systemic reactions [ Time Frame: 7 days after booster vaccination ]adult participants with single booster
- Frequency and severity of any unsolicited AE [ Time Frame: up to 6 months after booster dose ]adult participants with single booster
- Frequency and severity of any vaccine-related [ Time Frame: up to 6 months after booster dose ]adult participants with single booster
- Frequency and severity of any serious adverse event (SAE) [ Time Frame: up to 6 months after booster dose ]adult participants with single booster
- Frequency and severity of any adverse event of special interest (AESI) [ Time Frame: up to 6 months after booster dose ]adult participants with single booster
- Geometric mean fold rise (GMFR) with regards to SARS-CoV-2-specific neutralizing antibodies [ Time Frame: from day of booster vaccination to 14 days after booster vaccination ]adolescent participants with single booster
- GMT of SARS-CoV-2-specific neutralizing antibodies as measured by MNA50 [ Time Frame: Day of booser vaccination and 14 days post booster ]adolescent participants with single booster
- Proportion of participants with 4-fold increase with regards to SARS-CoV-2-specific neutralizing antibodies [ Time Frame: from day of booster vaccination to 14 days after booster vaccination ]adolescent participants with single booster
- GMFR with regards to S-protein binding antibodies [ Time Frame: from day of booster vaccination to 14 days after booster vaccination ]adolescent participants with single booster
- Proportion of participants with 4-fold increase with regards to S-protein binding antibodies [ Time Frame: from day of booster vaccination to 14 days after booster vaccination ]adolescent participants with single booster
- GMT measured as IgG antibodies against SARS-CoV-2 as determined by ELISA [ Time Frame: Day of booser vaccination and 14 days post booster ]adolescent participants with single booster
- Assessment of T-cell responses from PBMCs in a subset of participants after in vitro stimulation with SARS-CoV-2 antigens using ELISpot [ Time Frame: Day of booser vaccination and 14 days post booster ]adolescent participants with single booster
- Frequency and severity of solicited injection site and systemic reactions [ Time Frame: up to 7 days after booster vaccination ]adolescent participants with single booster
- Frequency and severity of any unsolicited AE [ Time Frame: 180 days post booster vaccination ]adolescent participants with single booster
- Frequency and severity of any serious adverse event (SAE) [ Time Frame: 180 days post booster vaccination ]adolescent participants with single booster
- Frequency and severity of any adverse event of special interest (AESI) [ Time Frame: 180 days post booster vaccination ]adolescent participants with single booster
- GMT measured as IgG antibodies against SARS-CoV-2 as determined by ELISA [ Time Frame: on day of booster vaccination, 14 days and 6 months post booster ]adult participants with single booster
- Frequency and severity of any vaccine related AE [ Time Frame: 180 days post booster vaccination ]adolescent participants with single booster

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Ages Eligible for Study: | 12 Years and older (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Participants must have read, understood, and signed the informed consent form (ICF).
- Participants of either gender aged 12 years and older at screening.
- Medically stable
- Must be able to attend all visits of the study and comply with all study procedures,
- Women of childbearing potential (WOCBP) must be able and willing to use at least 1 highly effective method of contraception for a minimum of 3 months after the last dose of study vaccine.
- WOCBPs must have a negative pregnancy test prior to each vaccination.
Exclusion Criteria:
- Participant is pregnant or planning to become pregnant within 3 months after study vaccine administration.
- History of allergy to any component of the vaccine.
- Significant infection (e.g. positive SARS-CoV-2 RT-PCR) or other acute illness, including fever > 100 °F (> 37.8 °C) 48 hours before vaccination.
- Participant has a known or suspected defect of the immune system
- Participant has a history of cerebral venous sinus thrombosis, heparin-induced thrombocytopenia or antiphospholipid syndrome.
- Participant has a history of malignancy in the past 5 years other than squamous cell or basal cell skin cancer. If there has been surgical excision or treatment more than 5 years ago that is considered to have achieved a cure, the participant may be enrolled. A history of hematologic malignancy is a permanent exclusion. Participants with a history of skin cancer must not be vaccinated at the previous tumour site.
- History of drug dependency or current use of drug of abuse or alcohol abuse at screening.
- Significant blood loss (> 450 mL) or has donated 1 or more units of blood or plasma within 6 weeks prior to the expected day of randomization (Visit 1).
- History of clinically significant bleeding disorder, or prior history of significant bleeding or bruising following IM injections or venepuncture.
- Severe and uncontrolled ongoing autoimmune or inflammatory disease History of Guillain-Barre syndrome or any other demyelinating condition.
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Any other significant disease, disorder or finding which in the opinion of the investigator may significantly increase the risk to the volunteer
Prior/concomitant therapy:
- Receipt of immunoglobulin or another blood product within the 3 months before expected day of randomization (visit 1) in this study or those who expect to receive immunoglobulin or another blood product during this study.
- Receipt of medications and or vaccinations intended to prevent COVID-19.
- Receipt of any vaccine (licensed or investigational), other than licensed influenza vaccine, within 28 days prior to the expected day of randomization (Visit 1).
- Any member of the study team or sponsor.
- An immediate family member or household member of the study's personnel.
Booster Vaccination (Adults and Adolescents)
In addition to the above-described eligibility criteria, the following criteria must be met:
1. Participant has not received another licensed COVID-19 vaccine during the study

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04864561

Study Chair: | Valneva Clinical Development | Valneva Austria GmbH |
Responsible Party: | Valneva Austria GmbH |
ClinicalTrials.gov Identifier: | NCT04864561 |
Other Study ID Numbers: |
VLA2001-301 |
First Posted: | April 29, 2021 Key Record Dates |
Last Update Posted: | March 20, 2023 |
Last Verified: | March 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Undecided |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
VLA2001 SARS-CoV-2 Virus Infection COVID-19 inactivated-adjuvanted SARS-CoV-2 virus vaccine |
Virus Diseases Infections |