Inclusion Criteria:

- Healthy people aged 3 years and above who have completed two or three doses of
CoronaVac at least 3 months (≥ 90 days) before (3-8 weeks interval for the first and
second dose of CoronaVac, and ≥3 months interval for the second and third dose);

- Participants (and/or their legal guardians for pediatric population) are able to
understand and sign the informed consent voluntarily;

- Pregnancy and contraception:

Female participants of childbearing potential (post-menarche and pre-menopause that has not
been undergone any sterilization surgery), who have a negative pregnancy test on the day of
booster vaccination in the present study, has practiced adequate contraception or has
abstained from all activities that could result in pregnancy for at least 28 days prior to
the day of vaccination, and agree to continue adequate contraception through 3 months
following the booster vaccination and are not currently breastfeeding; Male participants of
childbearing potential who agree to use adequate contraception through 3 months following
the booster vaccination (and/or your female partner agree to use an acceptable method of
birth control), which include refrain from donating sperm;

Note 1 :Adequate contraception is defined as consistent and correct use of an approved
contraceptive method in accordance with the product label. For example:

- Barrier method (such as condoms, diaphragm, or cervical cap) used in conjunction with
spermicide

- Intrauterine device

- Prescription hormonal contraceptive taken or administered via oral (pill), transdermal
(patch), subdermal, or IM route

- Sterilization of a female participant's monogamous male partner prior to entry into
the study Note 2 : Periodic abstinence (eg, calendar, ovulation, symptothermal,
post-ovulation methods) and withdrawal are not acceptable methods of contraception.

- Participants are able to comply with study procedures based on the assessment of
the Investigator;

- Participants willing to provide verifiable identification (following the local
regulations), to be contacted, and to contact the investigator during the study
period.

Exclusion Criteria:

- History of confirmed infection of SARS-CoV-2 within 3 months prior to study
vaccination；

- With positive test result of SARS-CoV-2 antigen during screening visit;

- Any prior administration of another investigational COVID-19 vaccine or other licensed
COVID-19 vaccines, or current/planned simultaneous participation in another
interventional study to prevent or treat COVID-19;

- Known allergy to vaccines or vaccine ingredients, and serious adverse reactions to
vaccines, such as urticaria, dyspnea, angioneurotic edema;

- Serious chronic disease, including but not limited to serious cardiovascular disease,
hypertension and diabetes that drugs cannot control, hepatorenal disease, malignant
tumor, etc;

- Acute central nervous system diseases such as encephalitis/myelitis, acute
disseminating encephalomyelitis, and related disorders;

- Significant chronic central nervous system diseases or neuromuscular disorders,
psychosis or severe cognitive behavioral disorder, in the opinion of the investigator,
including but not limited to epilepsy, autism spectrum disorder, intellectual
disabilities;

- History of autoimmune and/or hematological diseases (including but not limited to
systemic lupus erythematosus, thyroidectomy, autoimmune thyroid disease, hematological
malignancy, asplenia, functional asplenia, or splenectomy resulting from any
condition);

- History of bleeding disorders (e.g., factor deficiency, coagulopathy or platelet
disorder), or prior history of significant bleeding or bruising following IM
injections or venipuncture;

- Receipt of blood/plasma products or immunoglobulins in the past 3 months before
vaccination in this study;

- Participation in other studies involving study intervention within 30 days prior to
vaccination in this study;

- Receipt of attenuated live vaccines in the past 14 days prior to vaccination in this
study;

- Receipt of inactivated or subunit vaccines in the past 7 days prior to vaccination in
this study;

- Emerging of chronic diseases or acute exacerbation of stable chronic diseases
(including but not limited to asthma, migraine, gastrointestinal disorder, etc.)
within 30 days prior to vaccination in this study;

- Acute febrile illness, or body temperature ≥37.8°C on the day of vaccination;
enrollment could be considered if the fever is absent for 72 hours prior to
vaccination;

- According to the investigator's judgment, the participant has any other factors that
might interfere with the clinical trial results or pose additional risk to the
participant due to participation in the study.