Inclusion Criteria:

- Age range: healthy people aged 18 and above, who can provide legal identification;

- No history of t SARS-CoV-2 vaccination;

- Able to provide a negative nucleic acid test certificate for the new coronavirus
within 48 hours;

- Have the ability to understand (if illiterate, a fair witness is required to
accompany the informed consent) research procedures, have informed consent,
voluntarily sign the informed consent form, and be able to comply with the
requirements of the clinical research protocol；

- Inquire about medical history and physical examination, and the investigator judges
that the health status is good;

- Females of childbearing age (menarche to menopause) were not pregnant (negative
urine pregnancy test) at enrollment, were not breastfeeding, and had no reproductive
plans within the first 6 months after enrollment and took effective contraceptive
measures; 2 weeks prior to enrollment have taken effective contraceptive measures;

- Able and willing to complete the entire prescribed study plan throughout the study
follow-up period.

Exclusion Criteria:

First-dose exclusion criteria：

- Confirmed cases, suspected cases, asymptomatic infections, or close contacts of the
above-mentioned groups of SARS-CoV-2 infection (check "China Disease Prevention and
Control Information System");

- Axillary body temperature ≥37.3℃ before vaccination;

- Positive test for novel coronavirus antibody (IgG+IgM);

- Have a history of SARS virus infection (self-report, on-site inquiry);

- Fever (axillary temperature ≥37.3℃), dry cough, fatigue, nasal congestion, runny
nose, sore throat, myalgia, diarrhea, shortness of breath, and dyspnea within 14
days before vaccination;

- The test results of blood biochemistry, blood routine, urine routine and coagulation
function-related indexes before vaccination are abnormal, which are beyond the
reference value range and have clinically significant abnormalities;

- Severe allergic reactions (such as acute allergic reactions, urticaria, skin eczema,
dyspnea, angioedema or abdominal pain) have occurred in the past;

- Allergy to any component of the study vaccine (such as: aluminum, histidine, etc.);

- Patients with convulsions, epilepsy, encephalopathy or other progressive
neurological diseases (such as transverse myelitis, Guillain-Barre syndrome,
demyelinating diseases, etc.), long-term history of alcohol and drug abuse, history
of thyroidectomy, infectious diseases, mental illness medical or family history;

- Known or suspected diseases include: severe respiratory disease, severe liver and
kidney disease, severe cardiovascular disease, uncontrolled hypertension (systolic
blood pressure ≥140mmHg, diastolic blood pressure ≥90mmHg), diabetic complications,
malignant tumors, Various acute diseases, acute exacerbations of chronic diseases or
severe chronic diseases;

- Have been diagnosed with congenital or acquired immunodeficiency, HIV infection,
lymphoma, leukemia or other autoimmune diseases;

- Thrombocytopenia, history of abnormal coagulation function (such as coagulation
factor deficiency, coagulation disease);

- Asplenia or splenectomy, functional asplenia caused by any circumstance;

- Are receiving anti-TB (tuberculosis) treatment;

- Received immune enhancement or inhibitor therapy within 3 months (continuous oral or
infusion for more than 14 days);

- Received live attenuated vaccine within 28 days before vaccination, and received
other vaccines within 14 days before vaccination;

- Received blood products within 3 months before vaccination;

- Received other study drugs within 6 months before vaccination;

- Planning to move before the end of the study or to be away from the local area for
an extended period of time during a scheduled study visit;

- The investigator judges other circumstances that are not suitable to participate in
this clinical trial.

Exclusion criteria for second and third doses：

- Positive urine pregnancy test;

- Patients with abnormal conditions such as high fever (axillary temperature ≥39.0℃)
for three days, convulsions, severe allergic reactions or any adverse reactions of
the --Nervous system after the previous dose of vaccination;

- Serious adverse reactions that are causally related to the previous dose of
vaccination;

- For those newly discovered or newly discovered after the previous dose of vaccine
that do not meet the first-dose inclusion criteria or meet the first-dose exclusion
criteria, the investigator will determine whether to continue participating in the
study;

- Other reasons for exclusion considered by the investigator.