inclusion criteria: * is in good health * any underlying chronic illness must be documented to be in stable condition * has received a 2-dose primary series of the moderna mrna sars-cov-2 vaccine ≥5 months before receipt of study vaccine at visit 1 * may have received either: a) a first booster dose of the moderna mrna sars-cov-2 vaccine ≥4 months before receipt of study vaccine at visit 1, or b) no booster dose of the moderna mrna sars-cov-2 vaccine * a female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: is not a woman of childbearing potential (wocbp) or is a wocbp and using an acceptable contraceptive method, or is abstinent from heterosexual intercourse

inclusion criteria: * is in good health * any underlying chronic illness must be documented to be in stable condition * has received a 2-dose primary series of the moderna mrna sars-cov-2 vaccine ≥5 months before receipt of study vaccine at visit 1 * may have received either: a) a first booster dose of the moderna mrna sars-cov-2 vaccine ≥4 months before receipt of study vaccine at visit 1, or b) no booster dose of the moderna mrna sars-cov-2 vaccine * a female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: is not a woman of childbearing potential (wocbp) or is a wocbp and using an acceptable contraceptive method, or is abstinent from heterosexual intercourse

inclusion criteria: is in good health any underlying chronic illness must be documented to be in stable condition has received a 2-dose primary series of the moderna mrna sars-cov-2 vaccine ≥5 months before receipt of study vaccine at visit 1 may have received either: a) a first booster dose of the moderna mrna sars-cov-2 vaccine ≥4 months before receipt of study vaccine at visit 1, or b) no booster dose of the moderna mrna sars-cov-2 vaccine a female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: is not a woman of childbearing potential (wocbp) or is a wocbp and using an acceptable contraceptive method, or is abstinent from heterosexual intercourse

inclusion criteria: is in good health any underlying chronic illness must be documented to be in stable condition has received a 2-dose primary series of the moderna mrna sars-cov-2 vaccine ≥5 months before receipt of study vaccine at visit 1 may have received either: a) a first booster dose of the moderna mrna sars-cov-2 vaccine ≥4 months before receipt of study vaccine at visit 1, or b) no booster dose of the moderna mrna sars-cov-2 vaccine a female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: is not a woman of childbearing potential (wocbp) or is a wocbp and using an acceptable contraceptive method, or is abstinent from heterosexual intercourse

inclusion criteria: is in good health. any underlying chronic illness must be documented to be in stable condition. has received a 2-dose regimen of the moderna mrna sars-cov-2 vaccine ≥6 months before enrollment. a female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: is not a woman of childbearing potential (wocbp) or is a wocbp and using an acceptable contraceptive method, or is abstinent from heterosexual intercourse.

inclusion criteria: is in good health. any underlying chronic illness must be documented to be in stable condition. has received a 2-dose regimen of the moderna mrna sars-cov-2 vaccine ≥6 months before enrollment. a female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: is not a woman of childbearing potential (wocbp) or is a wocbp and using an acceptable contraceptive method, or is abstinent from heterosexual intercourse.