Part 1: Geometric Mean Concentration (GMC) of mRNA-1273.529 and mRNA-1273 Against the B.1.1.529 Strain at Day 29;Part 1: GMC of mRNA-1273.529 and mRNA-1273 Against the B.1.1.529 Strain at Day 85;Part 2: GMC of mRNA-1273.214 and mRNA-1273 Against the Ancestral Strain at Day 29;Part 2: GMC of mRNA-1273.214 and mRNA-1273 Against the Ancestral Strain ay Day 85;Part 2: GMC of mRNA-1273.214 and mRNA-1273 Against the B1.1.529 Strain at Day 29;Part 2: GMC of mRNA-1273.214 and mRNA-1273 Against the B1.1.529 Strain at Day 85;Parts 1 and 2: Number of Participants With AEs Leading to Withdrawal;Parts 1 and 2: Number of Participants With AEs of Special Interest (AESIs);Parts 1 and 2: Number of Participants With Medically Attended AEs (MAAEs);Parts 1 and 2: Number of Participants With Serious AEs (SAEs);Parts 1 and 2: Number of Participants With Unsolicited AEs;Parts 1 and 2: Percentage of Participants With Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)

Part 1: Geometric Mean Concentration (GMC) of mRNA-1273.529 and mRNA-1273 Against the B.1.1.529 Strain at Day 29;Part 1: GMC of mRNA-1273.529 and mRNA-1273 Against the B.1.1.529 Strain at Day 85;Part 2: GMC of mRNA-1273.214 and mRNA-1273 Against the Ancestral Strain at Day 29;Part 2: GMC of mRNA-1273.214 and mRNA-1273 Against the Ancestral Strain ay Day 85;Part 2: GMC of mRNA-1273.214 and mRNA-1273 Against the B1.1.529 Strain at Day 29;Part 2: GMC of mRNA-1273.214 and mRNA-1273 Against the B1.1.529 Strain at Day 85;Parts 1 and 2: Number of Participants With AEs Leading to Withdrawal;Parts 1 and 2: Number of Participants With AEs of Special Interest (AESIs);Parts 1 and 2: Number of Participants With Medically Attended AEs (MAAEs);Parts 1 and 2: Number of Participants With Serious AEs (SAEs);Parts 1 and 2: Number of Participants With Unsolicited AEs;Parts 1 and 2: Percentage of Participants With Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)

Geometric Mean Titer (GMT) of mRNA-1273.529 and mRNA-1273 Against the B.1.1.529 Strain;GMT of mRNA-1273.214 and mRNA-1273 Against the B1.1.529 Strain;GMT of mRNA-1273.214 and mRNA-1273 Against the Prototype Strain;Number of Participants with AEs Leading to Withdrawal;Number of Participants with AEs of Special Interest (AESIs);Number of Participants with Medically Attended AEs (MAAEs);Number of Participants with Serious AEs (SAEs);Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs);Number of Participants with Unsolicited Adverse Events (AEs)

Geometric Mean Titer (GMT) of mRNA-1273.529 and mRNA-1273 Against the B.1.1.529 Strain;GMT of mRNA-1273.214 and mRNA-1273 Against the B1.1.529 Strain;GMT of mRNA-1273.214 and mRNA-1273 Against the Prototype Strain;Number of Participants with AEs Leading to Withdrawal;Number of Participants with AEs of Special Interest (AESIs);Number of Participants with Medically Attended AEs (MAAEs);Number of Participants with Serious AEs (SAEs);Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs);Number of Participants with Unsolicited Adverse Events (AEs)

Geometric Mean Fold Rise (GMFR) of mRNA-1273.529 Against the B.1.1.529 Strain;Geometric Mean Titer (GMT) of mRNA-1273.529 and mRNA-1273 Against the B.1.1.529 Strain at Day 29 After Study Vaccine Administration;Number of Participants with AEs Leading to Withdrawal;Number of Participants with AEs of Special Interest (AESIs);Number of Participants with Medically Attended AEs (MAAEs);Number of Participants with Serious AEs (SAEs);Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs);Number of Participants with Unsolicited Adverse Events (AEs)

Geometric Mean Fold Rise (GMFR) of mRNA-1273.529 Against the B.1.1.529 Strain;Geometric Mean Titer (GMT) of mRNA-1273.529 and mRNA-1273 Against the B.1.1.529 Strain at Day 29 After Study Vaccine Administration;Number of Participants with AEs Leading to Withdrawal;Number of Participants with AEs of Special Interest (AESIs);Number of Participants with Medically Attended AEs (MAAEs);Number of Participants with Serious AEs (SAEs);Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs);Number of Participants with Unsolicited Adverse Events (AEs)