inclusion criteria: adult males or females aged 18 years and above at the time of consent. participants who provide a voluntarily consent to participate in the study and sign the consent form. participants who have previously received homologous 2-dose of sars-cov-2 vaccine (either vero cell inactivated-sinopharm sars-cov-2 vaccine, coronavac sars-cov-2 vaccine, or cominarty/pfizer mrna covid-19 vaccine) authorized for emergency use, between 6 to 12 months post second prime vaccine dose prior to day 1. participants who have negative results for swab sars-cov-2 rapid antigen test.

inclusion criteria: adult males or females aged 18 years and above at the time of consent. participants who provide a voluntarily consent to participate in the study and sign the consent form. participants who have previously received homologous 2-dose of sars-cov-2 vaccine (either vero cell inactivated-sinopharm sars-cov-2 vaccine, coronavac sars-cov-2 vaccine, or cominarty/pfizer mrna covid-19 vaccine) authorized for emergency use, between 6 to 12 months post second prime vaccine dose prior to day 1. participants who have negative results for swab sars-cov-2 rapid antigen test.