inclusion criteria: asymptomatic individuals exposed to a confirmed positive covid-19 case within 5 days from the study recruitment day (include household, workplace and social close contact) aged ≥18 years; male or female no fever with temperature less than 37.5ºc rtk ag for covid-19 is negative on the recruitment day. for subject who had received covid-19 vaccination: any primary series vaccine (eg: pfizer, sinovac, astrazeneca etc) : past 90 days after the second dose any booster vaccine: past 90 days after the booster dose in women of childbearing potential (18-55 years old), negative pregnancy test and agree to use any contraceptive method up to 7 days after the second dose of ip administration have access to video and phone call willing to take 2 doses of study medication (2 days apart between dose 1 and dose 2) willing to comply with all study procedures able to provide written informed consent

inclusion criteria: asymptomatic individuals exposed to a confirmed positive covid-19 case within 5 days from the study recruitment day (include household, workplace and social close contact) aged ≥18 years; male or female no fever with temperature less than 37.5ºc rtk ag for covid-19 is negative on the recruitment day. for subject who had received covid-19 vaccination: any primary series vaccine (eg: pfizer, sinovac, astrazeneca etc) : past 90 days after the second dose any booster vaccine: past 90 days after the booster dose in women of childbearing potential (18-55 years old), negative pregnancy test and agree to use any contraceptive method up to 7 days after the second dose of ip administration have access to video and phone call willing to take 2 doses of study medication (2 days apart between dose 1 and dose 2) willing to comply with all study procedures able to provide written informed consent

inclusion criteria: asymptomatic individuals exposed to a confirmed positive covid-19 case within 5 days from the study recruitment day (include household, workplace and social close contact) aged ≥18 years; male or female no fever with temperature less than 37.5ºc rtk ag for covid-19 is negative on the recruitment day. for subject who had received covid-19 vaccination: pfizer: post 6 months after the second dose sinovac: post 3 months after the second dose in women of childbearing potential (18-55 years old), negative pregnancy test and agree to use any contraceptive method up to 7 days after the second dose of ip administration have access to video and phone call willing to take 2 doses of study medication (2 days apart between dose 1 and dose 2) willing to comply with all study procedures able to provide written informed consent

inclusion criteria: asymptomatic individuals exposed to a confirmed positive covid-19 case within 5 days from the study recruitment day (include household, workplace and social close contact) aged ≥18 years; male or female no fever with temperature less than 37.5ºc rtk ag for covid-19 is negative on the recruitment day. for subject who had received covid-19 vaccination: pfizer: post 6 months after the second dose sinovac: post 3 months after the second dose in women of childbearing potential (18-55 years old), negative pregnancy test and agree to use any contraceptive method up to 7 days after the second dose of ip administration have access to video and phone call willing to take 2 doses of study medication (2 days apart between dose 1 and dose 2) willing to comply with all study procedures able to provide written informed consent