Efficacy: SARS-CoV-2 SPIKE/RBD IgG antibody levels 4 weeks after administration of the third vaccine dose. Safety: Hospital admissions or deaths due to vaccine adverse events 6 weeks after the third/fourth dose.

Efficacy: SARS-CoV-2 SPIKE/RBD IgG antibody levels 4 weeks after administration of the third vaccine dose. Safety: Hospital admissions or deaths due to vaccine adverse events 6 weeks after the third/fourth dose.

Efficacy: Change in SARS-CoV-2 SPIKE/RBD IgG antibody levels 3-5 weeks after administration of additional vaccine doses. Safety: Hospital admissions due to vaccine adverse events.

Efficacy: Change in SARS-CoV-2 SPIKE/RBD IgG antibody levels 3-5 weeks after administration of additional vaccine doses. Safety: Hospital admissions due to vaccine adverse events.