inclusion criteria: participants aged 18 years and above at the time of randomization. provide written informed consent. axillary temperature ≤ 37℃. never received any investigational or licensed covid-19 vaccine other than the 1st dose of sputnik v with an interval of 21-90 days before the study. subjects are eligible for immunization of this product as evaluated by investigators after medical history examination, physical examination and clinical judgment of health.

inclusion criteria: participants aged 18 years and above at the time of randomization. provide written informed consent. axillary temperature ≤ 37℃. never received any investigational or licensed covid-19 vaccine other than the 1st dose of sputnik v with an interval of 21-90 days before the study. subjects are eligible for immunization of this product as evaluated by investigators after medical history examination, physical examination and clinical judgment of health.