This study is a multicenter, randomized, double-blinded, placebo-controlled Phase III clinical trial. The objectives are to evaluate the efficacy, safety, and immunogenicity of ReCOV in adults aged 18 years and older who have not received any COVID-19 vaccination, and have no history of known COVID-19 in previous 6 months. Three-dose intramuscular (IM) vaccination schedule (21 days interval) will be applied.~About 10000 participants (about 15% participants ≥ 60 years old) with SARS-CoV-2 antibody (IgM and IgG) negative at baseline, will be randomized in a ratio of 1:1 to receive ReCOV (20 μg) or placebo on Day 0, Day 21, and Day 42, respectively. Participants will be stratified by age (18-59 years, ≥ 60 years) and study sites (if applicable).~For efficacy visits, study staff will contact participants on a weekly basis to remind reporting any signs or symptoms of COVID-19. If participants report any signs or symptoms that may be related to COVID-19, they will be required to immediately conduct an unscheduled visit under the instruction by site staff for COVID-19 related assessment and receiving treatment as deemed appropriate.~For reactogenicity and safety visits, all vaccinated participants will be observed for 30 minutes after each dose vaccination at study site for solicited or unsolicited AEs, and will be given subject diary to record solicited AEs within 7 days after each vaccination, and unsolicited AEs from the 1st vaccination to 28 days after the 3rd vaccination.~Approximately 800 participants will be included in the immunogenicity subgroup. Except for the efficacy and safety follow-up visits described above, this subgroup will be collected blood sample on Day 0 (pre-vaccination) and 14 days (+3 days), 6 months (±15 days) after the 3rd dose.
This is a multicenter designed Phase III clinical trial. About 10000 participants plan to be enrolled.The objectives of this study are to evaluate the efficacy, safety and immunogenicity of the recombinant two-component COVID-19 vaccine (CHO cell) in adults