inclusion criteria: * healthy people over 18 years old, and can provide vaccination information to prove that they have completed 2 doses of inactivated novel coronavirus vaccine (coronavac) within the past 3-9 months; * the subjects voluntarily participate in the research, sign the informed consent form, and can provide valid identification, understand and comply with the requirements of the study protocol; * female subjects of childbearing age agree to use effective contraception from the start of the study to 2 months after vaccination.

inclusion criteria: * healthy people over 18 years old, and can provide vaccination information to prove that they have completed 2 doses of inactivated novel coronavirus vaccine (coronavac) within the past 3-9 months; * the subjects voluntarily participate in the research, sign the informed consent form, and can provide valid identification, understand and comply with the requirements of the study protocol; * female subjects of childbearing age agree to use effective contraception from the start of the study to 2 months after vaccination.

inclusion criteria: healthy people over 18 years old, and can provide vaccination information to prove that they have completed 2 doses of inactivated novel coronavirus vaccine (coronavac) within the past 3-9 months; the subjects voluntarily participate in the research, sign the informed consent form, and can provide valid identification, understand and comply with the requirements of the study protocol; female subjects of childbearing age agree to use effective contraception from the start of the study to 2 months after vaccination.

inclusion criteria: healthy people over 18 years old, and can provide vaccination information to prove that they have completed 2 doses of inactivated novel coronavirus vaccine (coronavac) within the past 3-9 months; the subjects voluntarily participate in the research, sign the informed consent form, and can provide valid identification, understand and comply with the requirements of the study protocol; female subjects of childbearing age agree to use effective contraception from the start of the study to 2 months after vaccination.