inclusion criteria: * aged 3 years and above (after enrolled, subjects will be allocated according to age). * by asking for medical history and physical examination, the health condition judged by the investigators is well. * female subjects of childbearing age are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 3 months after enrolment. effective contraceptive measures have been taken within 2 weeks before inclusion. * no vaccination history of covid-19 vaccine before enrollment. * be able and willing to complete the whole prescribed study plan. * with self-ability to understand the study procedures, the informed consent \& voluntarily sign an informed consent form and be able to comply with the requirements of the protocol.

inclusion criteria: * aged 3 years and above (after enrolled, subjects will be allocated according to age). * by asking for medical history and physical examination, the health condition judged by the investigators is well. * female subjects of childbearing age are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 3 months after enrolment. effective contraceptive measures have been taken within 2 weeks before inclusion. * no vaccination history of covid-19 vaccine before enrollment. * be able and willing to complete the whole prescribed study plan. * with self-ability to understand the study procedures, the informed consent \& voluntarily sign an informed consent form and be able to comply with the requirements of the protocol.

inclusion criteria: - aged 3 years and above (after enrolled, subjects will be allocated according to age). - by asking for medical history and physical examination, the health condition judged by the investigators is well. - female subjects of childbearing age are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 3 months after enrolment. effective contraceptive measures have been taken within 2 weeks before inclusion. - no vaccination history of covid-19 vaccine before enrollment. - be able and willing to complete the whole prescribed study plan. - with self-ability to understand the study procedures, the informed consent & voluntarily sign an informed consent form and be able to comply with the requirements of the protocol.

inclusion criteria: - aged 3 years and above (after enrolled, subjects will be allocated according to age). - by asking for medical history and physical examination, the health condition judged by the investigators is well. - female subjects of childbearing age are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 3 months after enrolment. effective contraceptive measures have been taken within 2 weeks before inclusion. - no vaccination history of covid-19 vaccine before enrollment. - be able and willing to complete the whole prescribed study plan. - with self-ability to understand the study procedures, the informed consent & voluntarily sign an informed consent form and be able to comply with the requirements of the protocol.

inclusion criteria: - aged 3 years and above (after enrolled, subjects will be allocated according to age). - by asking for medical history and physical examination, the investigator judged that the health condition is well. - female subjects of childbearing age are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 3 months after enrolment. effective contraceptive measures have been taken within 2 weeks before inclusion. - no vaccination history of covid-19 vaccine before enrollment. - be able and willing to complete the whole prescribed study plan. - with self-ability to understand the study procedures, the informed consent & voluntarily sign an informed consent form and be able to comply with the requirements of the protocol.

inclusion criteria: - aged 3 years and above (after enrolled, subjects will be allocated according to age). - by asking for medical history and physical examination, the investigator judged that the health condition is well. - female subjects of childbearing age are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 3 months after enrolment. effective contraceptive measures have been taken within 2 weeks before inclusion. - no vaccination history of covid-19 vaccine before enrollment. - be able and willing to complete the whole prescribed study plan. - with self-ability to understand the study procedures, the informed consent & voluntarily sign an informed consent form and be able to comply with the requirements of the protocol.