inclusion criteria: healthy subjects aged 18 and over with full civil capacity who can provide vaccination information proving that they have received two doses of novel coronavirus inactivated vaccine (vero cells) in the last 3-13 months; subjects voluntarily participate in the study, sign informed consent, provide valid identification, understand and comply with the requirements of the study protocol; fertile men and women of reproductive age did not have sex from day 1 of the last menstrual cycle to day 1 of the study, or did not have sex with an effective contraceptive method and did not experience contraceptive failure (examples of contraceptive failure include male condom rupture during sex).subjects also agreed to use effective contraception from the time of signing informed consent to 1 month after trial vaccination.

inclusion criteria: healthy subjects aged 18 and over with full civil capacity who can provide vaccination information proving that they have received two doses of novel coronavirus inactivated vaccine (vero cells) in the last 3-13 months; subjects voluntarily participate in the study, sign informed consent, provide valid identification, understand and comply with the requirements of the study protocol; fertile men and women of reproductive age did not have sex from day 1 of the last menstrual cycle to day 1 of the study, or did not have sex with an effective contraceptive method and did not experience contraceptive failure (examples of contraceptive failure include male condom rupture during sex).subjects also agreed to use effective contraception from the time of signing informed consent to 1 month after trial vaccination.

inclusion criteria: 1. healthy subjects aged 18 and over with full civil capacity who can provide vaccination information proving that they have received two doses of novel coronavirus inactivated vaccine (vero cells) in the last 3-13 months; 2. subjects voluntarily participate in the study, sign informed consent, provide valid identification, understand and comply with the requirements of the study protocol; 3. fertile men and women of reproductive age did not have sex from day 1 of the last menstrual cycle to day 1 of the study, or did not have sex with an effective contraceptive method and did not experience contraceptive failure (examples of contraceptive failure include male condom rupture during sex).subjects also agreed to use effective contraception from the time of signing informed consent to 1 month after trial vaccination.

inclusion criteria: 1. healthy subjects aged 18 and over with full civil capacity who can provide vaccination information proving that they have received two doses of novel coronavirus inactivated vaccine (vero cells) in the last 3-13 months; 2. subjects voluntarily participate in the study, sign informed consent, provide valid identification, understand and comply with the requirements of the study protocol; 3. fertile men and women of reproductive age did not have sex from day 1 of the last menstrual cycle to day 1 of the study, or did not have sex with an effective contraceptive method and did not experience contraceptive failure (examples of contraceptive failure include male condom rupture during sex).subjects also agreed to use effective contraception from the time of signing informed consent to 1 month after trial vaccination.