Immunogenicity and Safety Study of SCB-2019 Vaccine as a Booster to COVID-19 Vaccine in Adults

Study Overview
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Brief Summary
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The purpose of this study is to assess the immunogenicity and safety of the investigational SCB-2019 vaccine, administered as a booster dose, to adults who: Received primary series with one of the selected authorized or investigational COVID-19 vaccines at least 3 months prior to enrollment. Received primary series and a booster dose of CoronaVac at least 3 months prior to enrollment.

Official Title
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A Multi-center, Observer-blind, Randomized, Controlled Phase 3 Study to Evaluate the Immunogenicity and Safety of Adjuvanted Recombinant SARS-CoV-2 Trimeric S-protein Subunit Vaccine (SCB-2019), Administered as a Booster Dose to Adults, Who Previously Received Primary Series of a COVID-19 Vaccine

Conditions
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COVID-19

Intervention / Treatment
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* Biological: Candidate vaccine, SCB-2019
* Biological: Comirnaty Vaccine
* Biological: Vaxzevria Vaccine
* Biological: CoronaVac Vaccine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male and female participants at least 18 years of age; Individuals willing and able to comply with study requirements, including all scheduled visits, vaccinations, laboratory tests, and other study procedures; Individuals willing and able to give an informed consent, prior to screening; Healthy participants or participants with pre-existing medical conditions who are in a stable medical condition; Individuals who received primary vaccination series with one of the selected COVID-19 vaccines (Comirnaty, Vaxzevria, or CoronaVac) ≥3 months prior to enrollment; or received primary series and a booster dose (≥3 months after primary series) of CoronaVac, ≥3 months prior to enrollment. Exclusion Criteria: Individuals with fever >37.5°C (axillary), or any acute illness at baseline (Day 1) or within 3 days prior to randomization; Individuals with laboratory-confirmed SARS-CoV-2 infection at Visit 1 (determined by positive Rapid Antigen Test or RT-PCR); Individuals who have received an investigational or licensed COVID-19 vaccine prior to Day 1 (except for primary series with Comirnaty, Vaxzevria, CoronaVac vaccines, or primary and booster dose of CoronaVac), or plan to receive COVID-19 vaccine during the study period; Individuals who have a history of severe adverse reaction associated with a vaccine or severe allergic reaction (e.g., anaphylaxis) to any component of the study vaccines; Individuals who have received any other investigational product within 30 days prior to Day 1 or intend to participate in another clinical study at any time during the conduct of this study.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group 1a (primary series: Comirnaty)<br>participants will receive one dose of SCB-2019 vaccine on Day 1 | Biological: Candidate vaccine, SCB-2019<br>* a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection<br>|
| Active Comparator: Group 1b (primary series: Comirnaty)<br>participants will receive one dose of Comirnaty vaccine on Day 1 | Biological: Comirnaty Vaccine<br>* intramuscular injection<br>|
| Experimental: Group 2a (primary series: Vaxzevria)<br>participants will receive one dose of SCB-2019 vaccine on Day 1 | Biological: Candidate vaccine, SCB-2019<br>* a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection<br>|
| Active Comparator: Group 2b (primary series: Vaxzevria)<br>participants will receive one dose of Vaxzevria vaccine on Day 1 | Biological: Vaxzevria Vaccine<br>* intramuscular injection<br>|
| Experimental: Group 3a (primary series: CoronaVac)<br>participants will receive one dose of SCB-2019 vaccine on Day 1 | Biological: Candidate vaccine, SCB-2019<br>* a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection<br>|
| Active Comparator: Group 3b (primary series: CoronaVac)<br>participants will receive one dose of CoronaVac vaccine on Day 1 | Biological: CoronaVac Vaccine<br>* intramuscular injection<br>|
| Experimental: Group 4a (primary series and booster dose CoronaVac)<br>participants will receive one dose of SCB-2019 vaccine on Day 1 | Biological: Candidate vaccine, SCB-2019<br>* a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection<br>|
| Active Comparator: Group 4b (primary series and booster dose CoronaVac)<br>participants will receive one dose of CoronaVac on Day 1; | Biological: CoronaVac Vaccine<br>* intramuscular injection<br>|
| Experimental: Group 4c (primary series and booster dose CoronaVac)<br>participants will receive a half dose of SCB-2019 vaccine on Day 1 | Biological: Candidate vaccine, SCB-2019<br>* a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection<br>|
| Experimental: Group 5a (primary series: CoronaVac)<br>participants will receive a dose of 2-vial presentation of SCB-2019 vaccine | Biological: Candidate vaccine, SCB-2019<br>* a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection<br>|
| Experimental: Group 5b (primary series: CoronaVac)<br>participants will receive a dose of 3-vial presentation of SCB-2019 vaccine | Biological: Candidate vaccine, SCB-2019<br>* a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| GMT ratio of GMT SCB-2019 over GMT Comirnaty on Day 15 |  | Day 15 | 
| GMT ratio of GMT SCB-2019 over GMT COVID-19 Vaccine Janssen on Day 15 |  | Day 15 | 
| GMT ratio of GMT SCB-2019 over GMT CoronaVac Vaccine on Day 15 |  | Day 15 | 
| Local and systemic solicited AEs reported within 7 days after study vaccination |  | Up to 7 days after each vaccination | 
| Unsolicited AEs reported from Visit 1 (Day 1) through Safety Call Day 29 |  | Up to Day 29 | 
| SAEs, AEs leading to early termination from the study, MAAEs, and AESIs |  | Through study completion, an average of 6 Months |