inclusion criteria: * age range: populations aged 18 years and above. * judged by the investigator that the health condition is well after inquiry and physical examination. * vaccinated with 2 doses/3 doses of inactivated covid-19 vaccine or mrna vaccine for ≥ 3 months. * female participants who are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 7 months after enrollment. effective contraceptive measures have been taken within 2 weeks before inclusion. * during the whole follow-up period of the study, 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 is able to comply with the requirements of the clinical study protocol.

inclusion criteria: * age range: populations aged 18 years and above. * judged by the investigator that the health condition is well after inquiry and physical examination. * vaccinated with 2 doses/3 doses of inactivated covid-19 vaccine or mrna vaccine for ≥ 3 months. * female participants who are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 7 months after enrollment. effective contraceptive measures have been taken within 2 weeks before inclusion. * during the whole follow-up period of the study, 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 is able to comply with the requirements of the clinical study protocol.

inclusion criteria: age range: populations aged 18 years and above. judged by the investigator that the health condition is well after inquiry and physical examination. vaccinated with 2 doses/3 doses of inactivated covid-19 vaccine or mrna vaccine for ≥ 3 months. female participants who are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 7 months after enrollment. effective contraceptive measures have been taken within 2 weeks before inclusion. during the whole follow-up period of the study, 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 is able to comply with the requirements of the clinical study protocol.

inclusion criteria: age range: populations aged 18 years and above. judged by the investigator that the health condition is well after inquiry and physical examination. vaccinated with 2 doses/3 doses of inactivated covid-19 vaccine or mrna vaccine for ≥ 3 months. female participants who are not nursing or pregnant at the time of enrolment (negative urine pregnancy test) and have no family planning within the first 7 months after enrollment. effective contraceptive measures have been taken within 2 weeks before inclusion. during the whole follow-up period of the study, 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 is able to comply with the requirements of the clinical study protocol.