inclusion criteria inclusion criteria of arm a: male and female healthy volunteers. age ≥18 years on study day 0. judged by the investigator to be healthy on the basis of medical history, physical examination and vital signs performed at screening. able to provide informed consent. able and willing to comply with all study procedures over follow-up period of approximately 6 months. for more inclusion criteria, please contact the investigator or sponsor. inclusion criteria of arm b: male and female healthy volunteers. received complete primary series of covid-19 inactivated vaccines not less than 6 months or received complete primary series of covid-19 mrna vaccines not less than 6 month. age ≥18 years on study day 0. judged by the investigator to be healthy on the basis of medical history, physical examination and vital signs performed at screening. able to provide informed consent . able and willing to comply with all study procedures over follow-up period of approximately 6 months. for more inclusion criteria, please contact the investigator or sponsor.

inclusion criteria inclusion criteria of arm a: male and female healthy volunteers. age ≥18 years on study day 0. judged by the investigator to be healthy on the basis of medical history, physical examination and vital signs performed at screening. able to provide informed consent. able and willing to comply with all study procedures over follow-up period of approximately 6 months. for more inclusion criteria, please contact the investigator or sponsor. inclusion criteria of arm b: male and female healthy volunteers. received complete primary series of covid-19 inactivated vaccines not less than 6 months or received complete primary series of covid-19 mrna vaccines not less than 6 month. age ≥18 years on study day 0. judged by the investigator to be healthy on the basis of medical history, physical examination and vital signs performed at screening. able to provide informed consent . able and willing to comply with all study procedures over follow-up period of approximately 6 months. for more inclusion criteria, please contact the investigator or sponsor.