inclusion criteria: * female participants of nonchildbearing potential may be enrolled in the study. nonchildbearing potential is defined as bilateral tubal ligation \>1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause. * female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding. * participant must have received their second dose of the mrna-1273 primary series at least 6 months prior to screening and enrollment (part a) or have received the mrna-1273 series and an mrna-1273 booster dose at least 3 months prior to screening and enrollment (part b).

inclusion criteria: * female participants of nonchildbearing potential may be enrolled in the study. nonchildbearing potential is defined as bilateral tubal ligation \>1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause. * female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding. * participant must have received their second dose of the mrna-1273 primary series at least 6 months prior to screening and enrollment (part a) or have received the mrna-1273 series and an mrna-1273 booster dose at least 3 months prior to screening and enrollment (part b).

inclusion criteria: female participants of nonchildbearing potential may be enrolled in the study. nonchildbearing potential is defined as bilateral tubal ligation >1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause. female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding. participant must have received their second dose of the mrna-1273 primary series at least 6 months prior to screening and enrollment (part a) or have received the mrna-1273 series and an mrna-1273 booster dose at least 3 months prior to screening and enrollment (part b).

inclusion criteria: female participants of nonchildbearing potential may be enrolled in the study. nonchildbearing potential is defined as bilateral tubal ligation >1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause. female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding. participant must have received their second dose of the mrna-1273 primary series at least 6 months prior to screening and enrollment (part a) or have received the mrna-1273 series and an mrna-1273 booster dose at least 3 months prior to screening and enrollment (part b).

inclusion criteria: female participants of nonchildbearing potential may be enrolled in the study. nonchildbearing potential is defined as bilateral tubal ligation >1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause. female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding. participant must have received their second dose of mrna-1273 vaccine at least 6 months prior to screening and enrollment.

inclusion criteria: female participants of nonchildbearing potential may be enrolled in the study. nonchildbearing potential is defined as bilateral tubal ligation >1 year prior to screening, bilateral oophorectomy, hysterectomy, or menopause. female participants of childbearing potential may be enrolled in the study if the participant has a negative pregnancy test on the day of vaccination (day 1), practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to day 1, agreed to continue adequate contraception through 3 months following the last vaccine administration, and not currently breastfeeding. participant must have received their second dose of mrna-1273 vaccine at least 6 months prior to screening and enrollment.