Phase I/II Clinical Trial to Evaluate the Safety, Tolerability and Immunogenicity of Recombinant SARS-CoV-2 Vaccine (CHO Cell) in Healthy People Aged 3 Years and Older

phase I study will evaluate safety and immunogenicity of a recombinant SARS-CoV-2 vaccine (CHO cell) in Chinese healthy population aged 3 years and older. 300 subjects will be enrolled and divided into 5 age groups: 18-59 years old group, 60-69 years old group, ≥70 years old group, 9-17 years old group and 3-8 years old group. In each group, there are two regimen cohort: low-dose at 0,30, 60 schedule and high-dose at 0,30,60 schedule. The subjects in regimen cohort will be randomized to receive vaccines or placebos at a ratio of 2:1. Phase II clinical study will explore dose and immunization procedures in 5 age groups, including 18-59 years old group, 60-69 years old group, ≥70 years old group, 9-17 years old group, and 3-8 years old group, with a total of 3280 subjects.