Inclusion Criteria:

1. Subjects aged 18 years and above when screening.

2. Participate voluntarily and sign an informed consent form and have the ability to
understand research procedures.

3. Negative SARS-CoV-2 nucleic acid test and SARS-CoV-2 IgM test.

4. Axillary body temperature is less than 37.3 degree centigrade on the day of
enrollment.

5. Without a history of SARS-CoV-2 infection or known SARS-CoV-2 infection more than 3
months prior to screening.

6. Fertile women take effective contraceptive measures 1 month before enrollment;
Fertile women (except those received hysterectomy, bilateral oophorectomy, tubal
ligation/salpingectomy) and men of childbearing potential voluntarily agree to take
effective contraceptive measures from screening to 3 months after vaccination and
without a plan of pregnancy and germ cell donation.

Exclusion Criteria:

1. Have a known allergy, hypersensitivity, or intolerance to the planned
investigational vaccine including any excipients of the vaccine. Have a known
anaphylactic shock and other serious adverse events to other vaccine.

2. Have a known history of SARS and MERS.

3. Administration of antipyretics, painkillers or anti-allergy drugs within 24 hours
prior to enrolment.

4. Receipt of subunit and/or inactivated vaccine within 7 days prior to vaccination or
receipt of any live attenuated vaccine within 14 days prior to vaccination.

5. History of SARS-CoV-2 vaccination within 3 months prior to enrollment; Participants
who received any immunoglobulin or blood products in the previous 3 months before
enrollment, or plan to receive similar products during the study.

6. Participants with the following diseases: ①Any acute diseases or acute attacks of
chronic diseases within 7 days prior to enrolment. ②Congenital malformations or
developmental disorders, genetic defects, severe malnutrition, etc. ③Congenital or
acquired immunodeficiency or autoimmune disease, or long-term receipt (>14
immunosuppressive agents within the past 6 months with exception of inhaled or
topical steroids, or short-term use （≤14 consecutive days） of oral corticosteroids.
④Currently suffering from or diagnosed with infectious diseases, or positive
screening results for human immunodeficiency virus antibody. ⑤History or family
history of neurological disorders (convulsions, epilepsy, encephalopathy, etc.) or
psychiatric disorders. ⑥Asplenia, or functional asplenia. ⑦Presence of severe,
uncontrollable or hospitalized cardiovascular diseases, diabetes, blood and
lymphatic diseases, immune diseases, liver and kidney diseases, respiratory
diseases, metabolic and skeletal diseases, or malignant tumors. ⑧Contraindications
to IM injections and blood draws, such as coagulation disorders, thrombotic or
bleeding disorders, or conditions that needs continuous anticoagulant usage.
⑨Hypertension not controlled by medication (on-site measurement: systolic blood
pressure ≥ 160mmHg and / or diastolic blood pressure ≥ 100mmHg).

7. Have a history of major surgery within 3 months before enrollment （based on the
judgment of the researchers）, or has not yet fully recovered from the surgery, or
has a major surgical plan during the study.

8. Those participating or planning to participate in other clinical trials during the
study period.

9. Those unsuitable for participating in the clinical trial as determined by the
investigator because of other abnormalities that are likely to confuse or confound
the study results, or non-conformance with the maximal benefits of the participants.

10. Exclusion criteria for selected populations: those who are pregnant or
breast-feeding or women of childbearing potential have a positive pregnancy test
prior to vaccination.