Approximately 300 participants aged 12-17 years old and previously vaccinated with 2 doses of mRNA COVID-19 vaccine (Comirnaty from Pfizer or mRNA-1273 from Moderna, participants previously vaccinated with mRNA1273 are more preferred) will be enrolled in this study and be randomly assigned to SCTV01E Group and mRNA-1273 Group in a ratio of 1:1.
The study is a randomized, double-blind, positive-controlled Phase II booster study. It will evaluate the immunogenicity and safety of SCTV01E compared with mRNA-1273 (the mRNA COVID-19 vaccine from Moderna) in population aged 12-17 years old and previously vaccinated with 2 doses of mRNA COVID-19 vaccine.