1. Safety - Clinical Adverse Events-AE (They will be measured as: -Occurrence of AE (Yes; No); -Description of AE (name of event); -Intensity of AE (mild; moderate; severe); -Casuality relationship ( unrelated; doubtful; possible; probable; definitive); -Measures adopted (None; Administration of any pharmacological therapy; Addition of a non-pharmacological therapy; Study exit; Hospitalization / prolongation of hospitalization); -Result (Completely resolved; Resolved with sequelae; Conditions in improvement; Condition present and unchanged; Worsening; Death caused by this event)). Measurement time: within 28 days after the application of each dose.2. Proportion of subjects with seroconversion of anti-RBD IgG antibodies to SARS-CoV-2 (seroconversion will be considered as that = 4 times the initial determination of the antibody titer). Measurement time: on days 14; 28 and 42 (for the short scheme 0-14-28) and 14; 28; 56 and 70 (for the long scheme 0-28-56); with respect to the baseline time.

1. Safety - Clinical Adverse Events-AE (They will be measured as: -Occurrence of AE (Yes; No); -Description of AE (name of event); -Intensity of AE (mild; moderate; severe); -Casuality relationship ( unrelated; doubtful; possible; probable; definitive); -Measures adopted (None; Administration of any pharmacological therapy; Addition of a non-pharmacological therapy; Study exit; Hospitalization / prolongation of hospitalization); -Result (Completely resolved; Resolved with sequelae; Conditions in improvement; Condition present and unchanged; Worsening; Death caused by this event)). Measurement time: within 28 days after the application of each dose.2. Proportion of subjects with seroconversion of anti-RBD IgG antibodies to SARS-CoV-2 (seroconversion will be considered as that = 4 times the initial determination of the antibody titer). Measurement time: on days 14; 28 and 42 (for the short scheme 0-14-28) and 14; 28; 56 and 70 (for the long scheme 0-28-56); with respect to the baseline time.

1. Safety - Clinical Adverse Events-AE (They will be measured as: -Occurrence of AE (Yes; No); -Description of AE (name of event); -Intensity of AE (mild; moderate; severe); -Casuality relationship ( unrelated; doubtful; possible; probable; definitive); -Measures adopted (None; Administration of any pharmacological therapy; Addition of a non-pharmacological therapy; Study exit; Hospitalization / prolongation of hospitalization); -Result (Completely resolved; Resolved with sequelae; Conditions in improvement; Condition present and unchanged; Worsening; Death caused by this event)). Measurement time: within 28 days after the application of each dose. 2. Proportion of subjects with seroconversion of anti-RBD IgG antibodies to SARS-CoV-2 (seroconversion will be considered as that >= 4 times the initial determination of the antibody titer). Measurement time: on days 14; 28 and 42 (for the short scheme 0-14-28) and 14; 28; 56 and 70 (for the long scheme 0-28-56); with respect to the baseline time.

1. Safety - Clinical Adverse Events-AE (They will be measured as: -Occurrence of AE (Yes; No); -Description of AE (name of event); -Intensity of AE (mild; moderate; severe); -Casuality relationship ( unrelated; doubtful; possible; probable; definitive); -Measures adopted (None; Administration of any pharmacological therapy; Addition of a non-pharmacological therapy; Study exit; Hospitalization / prolongation of hospitalization); -Result (Completely resolved; Resolved with sequelae; Conditions in improvement; Condition present and unchanged; Worsening; Death caused by this event)). Measurement time: within 28 days after the application of each dose. 2. Proportion of subjects with seroconversion of anti-RBD IgG antibodies to SARS-CoV-2 (seroconversion will be considered as that >= 4 times the initial determination of the antibody titer). Measurement time: on days 14; 28 and 42 (for the short scheme 0-14-28) and 14; 28; 56 and 70 (for the long scheme 0-28-56); with respect to the baseline time.