Fig. 1: Trial profile.

*Other: Vaccine group participants without corresponding control population. During the study period, CoronaVac® was approved for EUA (Emergency Use Authorization) in Chile for a population aged 3–17 years. Hence, participants aged 3–17 years in Chile (343 aged 6–17 years and 416 aged 3–5 years) were unblinded and administrated CoronaVac®. The data of these subjects were excluded from the efficacy analysis#. One participant, who was enrolled in the placebo group at the beginning of the study, had the first dose of placebo. However, this participant received CoronaVac® in the second injection. Thus, after the second dose, this participant was moved to the vaccine group in the safety analysis.