Number of Participants With Medically-Attended Adverse Events (MAAEs);Number of Participants With SAEs;Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs);Number of Participants With Unsolicited AEs;Part A: Level of Severe Acute Respiratory Syndrome Coronavirus (SARS-COV-2)-Specific Binding Antibody (bAb) as Measured by Enzyme-Linked Immunosorbent Assay (ELISA);Part B: Level of SARS-CoV-2-Specific bAb as Measured by ELISA;Part C: Level of SARS-CoV-2-Specific bAb as Measured by MSD

Number of Participants With Medically-Attended Adverse Events (MAAEs);Number of Participants With SAEs;Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs);Number of Participants With Unsolicited AEs;Part A: Level of Severe Acute Respiratory Syndrome Coronavirus (SARS-COV-2)-Specific Binding Antibody (bAb) as Measured by Enzyme-Linked Immunosorbent Assay (ELISA);Part B: Level of SARS-CoV-2-Specific bAb as Measured by ELISA;Part C: Level of SARS-CoV-2-Specific bAb as Measured by MSD

Change from Baseline in the Measure of Clinical Safety Laboratory Values in Cohort 2;Level of SARS-CoV-2-Specific Binding Antibody (bAb) as Measured by Enzyme-Linked Immunosorbent Assay (ELISA);Number of Participants with Abnormalities in Blood Pressure, Temperature, HR, or Respiratory Rate;Number of Participants with Abnormalities in Physical Examinations;Number of Participants with Medically-Attended Adverse Events (MAAEs);Number of Participants with Serious Adverse Events (SAEs);Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs);Number of Participants with Unsolicited Adverse Events (AEs)

Change from Baseline in the Measure of Clinical Safety Laboratory Values in Cohort 2;Level of SARS-CoV-2-Specific Binding Antibody (bAb) as Measured by Enzyme-Linked Immunosorbent Assay (ELISA);Number of Participants with Abnormalities in Blood Pressure, Temperature, HR, or Respiratory Rate;Number of Participants with Abnormalities in Physical Examinations;Number of Participants with Medically-Attended Adverse Events (MAAEs);Number of Participants with Serious Adverse Events (SAEs);Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs);Number of Participants with Unsolicited Adverse Events (AEs)

Change in the measure of clinical safety laboratory values in Cohort 2 from baseline;Evaluate immunogenicity of mRNA-1273 by titer of SARS-CoV-2-specific binding antibody (bAb) measured by enzyme-linked immunosorbent assay (ELISA);Number of Participants with Medically-Attended Adverse Events (MAAEs);Number of Participants with Serious Adverse Events (SAEs);Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs);Number of Participants with Unsolicited Adverse Events (AEs);The number and percentage of participants with abnormalities in blood pressure, temperature, HR or respiratory rate will be assessed.;The number and percentage of participants with abnormalities in physical examinations will be assessed

Change in the measure of clinical safety laboratory values in Cohort 2 from baseline;Evaluate immunogenicity of mRNA-1273 by titer of SARS-CoV-2-specific binding antibody (bAb) measured by enzyme-linked immunosorbent assay (ELISA);Number of Participants with Medically-Attended Adverse Events (MAAEs);Number of Participants with Serious Adverse Events (SAEs);Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs);Number of Participants with Unsolicited Adverse Events (AEs);The number and percentage of participants with abnormalities in blood pressure, temperature, HR or respiratory rate will be assessed.;The number and percentage of participants with abnormalities in physical examinations will be assessed

Serious adverse events (SAEs);Unsolicited adverse events (AEs);Solicited local and systemic adverse reactions (ARs);Change in the measure of clinical safety laboratory values in Cohort 2 from baseline;Medically-attended adverse events (MAAEs);The number and percentage of participants with abnormalities in blood pressure, temperature, HR or respiratory rate will be assessed.;Evaluate immunogenicity of mRNA-1273 by titer of SARS-CoV-2-specific binding antibody (bAb) measured by enzyme-linked immunosorbent assay (ELISA);The number and percentage of participants with abnormalities in physical examinations will be assessed

Serious adverse events (SAEs);Unsolicited adverse events (AEs);Solicited local and systemic adverse reactions (ARs);Change in the measure of clinical safety laboratory values in Cohort 2 from baseline;Medically-attended adverse events (MAAEs);The number and percentage of participants with abnormalities in blood pressure, temperature, HR or respiratory rate will be assessed.;Evaluate immunogenicity of mRNA-1273 by titer of SARS-CoV-2-specific binding antibody (bAb) measured by enzyme-linked immunosorbent assay (ELISA);The number and percentage of participants with abnormalities in physical examinations will be assessed