inclusion criteria: * adults 18 to 75 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. for mrna-1647 study arms, adults 18 to \<50 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. * body mass index (bmi) of 18 kilograms (kg)/square meter (m\^2) to 35 kg/m\^2 (inclusive) at the screening visit.

inclusion criteria: * adults 18 to 75 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. for mrna-1647 study arms, adults 18 to \<50 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. * body mass index (bmi) of 18 kilograms (kg)/square meter (m\^2) to 35 kg/m\^2 (inclusive) at the screening visit.

inclusion criteria: adults 18 to 75 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. for mrna-1647 study arms, adults 18 to <50 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. body mass index (bmi) of 18 kilograms (kg)/square meter (m^2) to 35 kg/m^2 (inclusive) at the screening visit.

inclusion criteria: adults 18 to 75 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. for mrna-1647 study arms, adults 18 to <50 years of age at the time of consent (screening visit) who, in the opinion of the investigator, are in good health based on review of medical history and physical examination performed at screening. body mass index (bmi) of 18 kilograms (kg)/square meter (m^2) to 35 kg/m^2 (inclusive) at the screening visit.