Omicron BA.4/5-Delta COVID-19 Vaccine Phase I Clinical Trial

Inclusion Criteria: * Aged 18 and above when signing the informed consent form; * The subject himself voluntarily participates in this research, and signs the informed consent form, and can provide legal identification, understand and abide by the requirements of the trial protocol; * Female subjects of childbearing age and male subjects must agree to take effective contraceptive measures during the study. Exclusion Criteria: * Less than 6 months since the last COVID-19 infection or COVID-19 vaccination； * Prior history of severe allergy to any vaccine, or to any component of the experimental vaccine, including aluminum preparations, such as anaphylactic shock, allergic laryngeal edema, anaphylactoid purpura, thrombocytopenic purpura, dyspnea, angioneurotic edema, allergy (such as allergy to two or more drugs, food or pollen); * Suspected or confirmed fever (axillary temperature ≥37.3℃/ mouth temperature ≥37.5℃) within 72 hours before enrollment, or axillary body temperature ≥37.3℃/ mouth temperature ≥37.5℃ on the day of enrollment; * Patients with uncontrolled lymphoproliferative disease, unmitigated aplastic anemia, primary immune thrombocytopenia (ITP) activity, uncontrolled coagulation disease, etc.; * a history of congenital or acquired immunodeficiency or autoimmune disease; Absence of spleen, or history of splenic surgery, trauma or immunomodulator treatment within 6 months, such as immunosuppressive dose of glucocorticoids (dose reference: equivalent to prednisone 20mg/ day for more than a week); Or monoclonal antibodies; Thymosin; Or interferon; Topical use (such as ointments, eye drops, inhalants or nasal sprays) is permitted; * Non-live vaccine should be administered within 14 days before vaccination, and live attenuated vaccine should be administered within 30 days; * Patients with malignant tumors who are undergoing chemotherapy, radiotherapy, immunotherapy, etc., before and after surgery; Patients with organ transplant status; * People with uncontrolled epilepsy and other progressive neurological disorders (e.g. Transverse myelitis, Guillain-Barre syndrome, demyelinating diseases, etc.); * Patients with acute disease, or acute onset of chronic disease, or uncontrolled severe chronic disease, such as medically uncontrolled hypertension (systolic blood pressure ≥160mmHg and/or diastolic blood pressure ≥100mmHg); * Participants who had used blood and blood-related products within 3 months prior to enrollment; * Participants who have participated in or are participating in other clinical trials (including drugs and devices) within 3 months prior to the clinical trial; * Women of childbearing age have had unprotected sexual activity within 14 days prior to enrollment * lactating women or women during pregnancy; * The investigator determined that the subject had any disease or condition that would put the subject at risk, that the subject would not be able to complete the trial as required by the protocol, or that there would be conditions that would interfere with the evaluation of vaccine response.