Fig. 1: CONSORT Flow diagram of the study.

Participants were enrolled from July 21, 2021 to December 22, 2021. The safety population included all participants who received at least one dose of the MVC-COV1901 vaccine or placebo. The per protocol set (PPS) population consisted of participants who received the two doses of MVC-COV1901 or placebo as scheduled, and were seronegative at baseline with anti-nucleocapsid (anti-N) antibodies negative at Visit 2 and Visit 6, and did not have a major protocol deviations. Detailed reasons for exclusion from the PPS can be found in Supplementary Table 2.