Phase II: Geometric mean titers (GMT) and seroconversion rate of total IgG antibody (ELISA method) against the SARS-CoV-2 Alpha, Beta and Delta variants on Day 14 after the second dose of vaccination;;Phase II: GMT and seroconversion rate of neutralizing antibody (Live-virus neutralization assay) against the Alpha and Beta variants of SARS-CoV-2 on Day 14 after the second dose of vaccination;;Phase II: GMT and seroconversion rate of neutralizing antibody (Pseudovirus neutralization assay) against the SARS-CoV-2 Alpha and Beta variants on Day 14 after the second dose of vaccination;;Phase II: Incidence and severity of solicited AEs from Day 0 to Day 7 after each dose of vaccination;;Phase I: Incidence and severity of adverse reactions (ARs) from Day 0 to Day 7 days after each dose of vaccination.

Phase II: Geometric mean titers (GMT) and seroconversion rate of total IgG antibody (ELISA method) against the SARS-CoV-2 Alpha, Beta and Delta variants on Day 14 after the second dose of vaccination;;Phase II: GMT and seroconversion rate of neutralizing antibody (Live-virus neutralization assay) against the Alpha and Beta variants of SARS-CoV-2 on Day 14 after the second dose of vaccination;;Phase II: GMT and seroconversion rate of neutralizing antibody (Pseudovirus neutralization assay) against the SARS-CoV-2 Alpha and Beta variants on Day 14 after the second dose of vaccination;;Phase II: Incidence and severity of solicited AEs from Day 0 to Day 7 after each dose of vaccination;;Phase I: Incidence and severity of adverse reactions (ARs) from Day 0 to Day 7 days after each dose of vaccination.