The purpose of this double-blind, randomized, controlled study is to evaluate the efficacy,
immunogenicity, reactogenicity and safety of an adjuvanted recombinant severe acute
respiratory syndrome coronavirus 2 (SARS-CoV-2) trimeric spike (S)-protein subunit vaccine
(SCB-2019) for the prevention of SARS-CoV-2-mediated COVID-19 in adult subjects 18 years of
age and above.
Primary Outcomes
Measure: Number of Participants with a First Occurrence of COVID-19 of Any Severity Starting 14 Days after Second Dose of SCB-2019 Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Number of Participants with a First Occurrence of Moderate-to-Severe COVID-19 Starting 14 Days after Second Dose of SCB-2019 Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs) Time: Up to Day 8 (7 days after first dose) and up to Day 29 (7 days after second dose)
Measure: Number of Participants with Unsolicited AEs Time: Up to Day 43 (21 days after each dose)
Measure: Number of Participants with Serious Adverse Events (SAEs), or Medically Attended AEs (MAAEs), or AEs Leading to Early Termination, or Adverse Events of Special Interest (AESIs) Time: Up to Day 389 (1 year after second dose)
Secondary Outcomes
Measure: Number of Participants with First Occurrence of Any Laboratory-Confirmed SARS-CoV-2 infection Starting 14 Days after Second Dose of SCB-2019 or Placebo Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Number of Participants with a First Occurrence of Severe COVID-19 Starting 14 Days after Second Dose of SCB-2019 or Placebo Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Number of Participants with First Occurrence of Any Laboratory-Confirmed Asymptomatic SARS-CoV-2 infection Starting 14 Days after Second Dose of SCB-2019 or Placebo Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Burden of Disease Score of COVID-19 or SARS-CoV-2 Infection Cases Starting 14 Days after Second Dose of SCB-2019 or Placebo Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Number of Participants with a First Occurrence of COVID-19 of Any Severity, Associated with Hospitalization, Starting 14 Days after Second Dose of SCB-2019 or Placebo Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Number of Participants with a First Occurrence of COVID-19 Starting 14 days after Second Dose of SCB-2019 or Placebo, regardless of evidence of prior SARS-CoV-2 Infection Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Number of Participants with a First Occurrence of COVID-19 Starting 14 days after Second Dose of SCB-2019 or Placebo, regardless of risk of severe COVID-19 Time: Day 36 up to Day 389 (1 year after second dose)
Measure: Number of Participants with a First Occurrence of COVID-19 Starting 14 days after First Dose of SCB-2019 or Placebo Time: Day 15 up to Day 389 (1 year after second dose)
Measure: Geometric Mean Titer (GMT) of SARS-CoV-2 Specific Neutralizing Antibody (nAb) Time: Day 1, Day 22, Day 35, Day 205, and Day 389
Measure: Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Specific nAb Time: Day 1, Day 22, Day 35, Day 205, and Day 389
Measure: Number of Participants with Seroconversion for SARS-CoV-2 Specific nAb Time: Day 22, and Day 35
Measure: Geometric Mean Titer (GMT) of SARS-CoV-2 antibodies competing for binding of S protein to the human ACE2 receptor Time: Day 1, Day 22, Day 35, Day 205, and Day 389
Measure: Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 antibodies competing for binding of S protein to the human ACE2 receptor Time: Day 1, Day 22, Day 35, Day 205, and Day 389
Measure: Number of Participants with Seroconversion for of SARS-CoV-2 antibodies competing for binding of S protein to the human ACE2 receptor Time: Day 22, and Day 35
Measure: Geometric Mean Titer (GMT) of SCB-2019 binding antibody Time: Day 1, Day 22, Day 35, Day 205, and Day 389
Measure: Geometric Mean Fold Rise (GMFR) of SCB-2019 binding antibody Time: Day 1, Day 22, Day 35, Day 205, and Day 389
Measure: Number of Participants with Seroconversion for SCB-2019 binding antibody Time: Day 22, and Day 35
Measure: Geometric Mean Titer (GMT) of Trimer-Tag binding antibody Time: Day 1, Day 22, Day 35, Day 205, and Day 389
Measure: Geometric Mean Fold Rise (GMFR) of Trimer-Tag binding antibody Time: Day 1, Day 22, Day 35, Day 205, and Day 389