A Global, Multi-center, Randomized, Double-Blind, Placebo-Controlled, Phase III Clinical Study to Evaluate the Efficacy, Safety, and Immunogenicity of Recombinant SARS-CoV-2 Fusion Protein Vaccine (V-01) in Adults Aged 18 Years and Older

This is a global, multicenter, randomized, double-blind, placebo-controlled, parallel-group phase III clinical study. Approximately 22,500 participants aged 18 years and older will be enrolled in this study to evaluate the efficacy, safety and immunogenicity of recombinant SARS-CoV-2 fusion protein vaccine (code: V-01, hereinafter referred to as V-01).

The eligible participants will be randomized in a 2:1 ratio into investigational vaccine group (V-01) and placebo group, with random stratification factors including 1) age (18-59 years vs ≥60 years); 2) gender (male vs female); and 3) whether or not being enrolled into immunogenicity subgroup (yes vs no). The participants will receive investigational vaccine V-01 or placebo on two doses schedule (one dose each on day 0 and 21, with +7 days' time window for the second dose).

Inclusion Criteria:

The participants can be enrolled only all of the following criteria are met:

1. Voluntarily participate in this study and sign the informed consent form;
2. Adults aged 18 years and older, male or female;
3. According to the assessment of the investigator, the participant has a stable medical condition (which is defined as no significant changes in therapy or hospitalization caused by disease aggravation within 3 months before enrollment) and is able to and willing to follow the requirements of the protocol.
4. Males of reproductive potential and females of child-bearing potential voluntarily agree to take effective and acceptable contraceptive methods from the signing of informed consent form to 12 months after full-course immunization; females of child-bearing potential have a negative pregnancy test at screening and at the day of vaccination.

Exclusion Criteria:

Participants meeting any of the following exclusion criteria will not be allowed to participate in this study:

1.History of previous COVID-19 infection; 2.Positive result for RT-PCR test in the screening period or specific antibody IgG or IgM meet the following criteria:

1. If IgG is positive, the participant will be excluded regardless of the results of other indexes.
2. If IgG is negative and IgM is positive, it will be determined whether or not to enroll such participant after the result of RT-PCR test is obtained;
3. If both IgG and IgM are negative, the participant can be vaccinated without waiting for the RT-PCR test results.

3.History of severe acute respiratory syndrome (SARS), middle east respiratory syndrome (MERS), and other human coronavirus infections or diseases; 4.History of severe allergy to any vaccine, e.g., acute allergic reactions, urticaria, skin eczema, dyspnea, angioneurotic edema or abdominal pain etc., or be allergic to any components of V-01; 5.Any confirmed or suspected immunosuppression or immunodeficiency condition known from medical history, including human immunodeficiency virus (HIV) infection, asplenia; 6.Serious or uncontrolled cardiovascular diseases, nervous system disorders (e.g., Guillain-Barre syndrome), blood and lymphatic system disorders, immune system disorders, hepatorenal disorders, respiratory system disorders (e.g., active tuberculosis, pulmonary fibrosis), metabolic and skeletal systems disorders or malignant tumors (except for skin basal cell carcinoma or in situ carcinoma of uterine cervix that has been cured for more than 5 years); 7.Hereditary hemorrhagic tendency or coagulation dysfunction, or a history of thrombosis or hemorrhagic disease, or requirement of continuous use of anticoagulants; 8.Prior use of any medications to prevent COVID-19, e.g., use of antipyretics without pyrexia and any other symptoms; 9.A history of vaccination against SARS-CoV-2 (marketed or investigational); 10.Received attenuated live vaccine within 28 days before the first vaccination or any other vaccines (licensed or investigational) within 14 days before the first vaccination; 11.Injection of immunoglobulin and/or other blood products within 3 months before the administration of study vaccine; 12.Long-term use (continuous use >14 days) of glucocorticoids (≥10mg/day of prednisone or its equivalent dose) or other immunosuppressive agents; however, enrollment is allowed for the following conditions: inhaled or topical use of topical steroids, or short-term use (treatment course ≤14 days) of oral steroids; 13.Pregnant or breastfeeding women; 14.Planning to donate blood during the study period; 15.Suspected or known alcohol or drug dependence; 16.History of severe psychiatric disorders which may affect study participation; 17.Planning to permanently move from the local area before study completion or leave the local area for a long time during the period of study visits, so that the scheduled visits cannot be followed; 18.Those considered by the investigator as inappropriate to participate in the study.