inclusion criteria: * health subjects aged ≥18 years. * have received two-dose inactivated sars-cov-2 vaccine before 6 months or more. * the subject can provide with informed consent and sign informed consent form (icf). * the subjects are able to and willing to comply with the requirements of the clinical trial program and could complete the 6-month follow-up of the study.

inclusion criteria: * health subjects aged ≥18 years. * have received two-dose inactivated sars-cov-2 vaccine before 6 months or more. * the subject can provide with informed consent and sign informed consent form (icf). * the subjects are able to and willing to comply with the requirements of the clinical trial program and could complete the 6-month follow-up of the study.

inclusion criteria: health subjects aged ≥18 years. have received two-dose inactivated sars-cov-2 vaccine before 6 months or more. the subject can provide with informed consent and sign informed consent form (icf). the subjects are able to and willing to comply with the requirements of the clinical trial program and could complete the 6-month follow-up of the study.

inclusion criteria: health subjects aged ≥18 years. have received two-dose inactivated sars-cov-2 vaccine before 6 months or more. the subject can provide with informed consent and sign informed consent form (icf). the subjects are able to and willing to comply with the requirements of the clinical trial program and could complete the 6-month follow-up of the study.