Clinical Trial of COVID-19 Vaccine（SARS-CoV-2 Variant(Omicron BA.5) mRNA Vaccine） in Participants Aged 18 Years and Over

Inclusion Criteria:

1. Both male and female adults aged 18 and above who can provide identification;
2. Know the contents of the informed consent form and the situation of the vaccination,sign the informed consent form voluntarily, and have the ability to use thethermometer, scale and fill in the diary card and contact card as required;
3. Ability to communicate well with researchers, understand and comply with therequirements of the study;
4. Two or three doses of COVID-19 inactivated vaccine have been completed and ≥6 monthshave passed since the last dose of COVID-19 inactivated vaccine;
5. Healthy subjects or subjects with mild underlying diseases [stable condition with noworsening condition (no need for hospitalization or no major adjustment in treatmentregimen, etc.) for at least 3 months prior to inclusion in the study];
6. Women who are not possibility to have children (amenorrhea for at least 1 year orsurgical sterilization with medical records) or who are known not to be pregnant orlactating and who have used effective contraception for nearly 14 days beforevaccination (e.g., Intrauterine or implantable contraceptive devices,oralcontraceptives, injected or embedded contraceptives, slow-release topicalcontraceptives, intrauterine devices (IUD), condoms (male), diaphragm, cervical cap,etc.) (provide negative proof of pregnancy within 48 hours);
7. SARS-CoV-2 etiology test (RT-PCR) was negative within 48 hours.

Exclusion Criteria:

1. Abnormal vital signs that are clinically significant (e.g. abnormal controlled bloodpressure);
2. Have been infected with COVID-19 or used any COVID-19 prophylactic medication otherthan 3 doses of COVID-19 inactivated vaccine within the last 6 months (for example, ahistory of any other non-COVID-19 inactivated vaccine on or off the market, or 1 or 4doses of COVID-19 inactivated vaccine);
3. History of severe acute respiratory syndrome (SARS), Middle East Respiratory Syndrome (MERS) and other human coronavirus infection or disease history;
4. Axillary temperature ≥37.3℃ or fever within 24 hours on the day of vaccination (axillary temperature ≥37.3℃/ mouth temperature ≥37.5℃);
5. A history of severe allergic reactions or allergic reactions to vaccines or drugs,such as urticaria, severe eczema, dyspnea, laryngeal edema, angioneurotic edema, etc.;
6. Vaccination of any vaccine within 28 days prior to study vaccination;
7. Enrolled in a clinical study of another drug within 28 days before vaccination orplanned to participate in a clinical study of another drug within 6 months aftervaccination;
8. Have a genetic tendency to bleed or abnormal coagulation function (e.g. cytokinedeficiency, coagulation disorder or thrombocytopenia), or a history of severebleeding;
9. A known history or diagnosis of a disease affecting immune system function, such ascancer (other than basal cell carcinoma of the skin), congenital or acquiredimmunodeficiency (e.g., HIV infection), uncontrolled autoimmune disease, etc.;
10. Asplenia or functional asplenia;
11. Long-term use (continuous use ≥14 days) of immunosuppressants or otherimmunomodulatory drugs (e.g., cortisol: prednisone or similar drugs) within 6 monthsprior to study vaccination; Interferon, etc.), but topical use (such as ointments, eyedrops, inhalants or nasal sprays) is permitted, and the dose of topical use shall notexceed that recommended in the instructions;
12. Received immunoglobulin and/or blood products within 3 months prior to studyvaccination;
13. Suspected or known alcohol dependence or drug abuse;
14. Other factors considered inappropriate to be included in the study.