Fig. 2: Cohort enrollment process.

Cohort selection for the analysis of effectiveness of vaccination with inactivated vaccine (A: Cohort 1) and booster vaccination with inactivated vaccine (B: Cohort 2).
Cohort selection for the analysis of effectiveness of vaccination with inactivated vaccine (A: Cohort 1) and booster vaccination with inactivated vaccine (B: Cohort 2).