Inclusion Criteria:  Has provided written consent for participation Age between 20 and 55 Has a negative nucleic acid-based test result for SARS-CoV-2 Has a negative antibody test result for SARS-CoV-2  Exclusion Criteria:  Signs and symptoms consistent with COVID-19 upon screening History of COVID-19 Presence of uncontrolled cardiovascular, hematologic, respiratory, hepatic, renal, gastrointestinal, or neuropsychiatric disease Presence of diabetes mellitus Presence of active autoimmune disease Positive for HBc, HCV or HIV antibody History of anaphylactic shock History of epilepsy Presence of active malignancy Presence of lung disease (e.g., COPD, asthma) Positive urine pregnancy test within 24 hours Pregnant, lactating, planned pregnancy of self (if female) or partner (if male) within 90 days after administration of the trial drug If female and premenopausal, not agreeable to contraception for 90 days after second administration of the trial drug If male, not agreeable to contraception for 90 days after second administration of the trial drug Presence of clinically relevant electrocardiogram or vital sign abnormality at screening Participated in a clinical trial of a drug or a medical device within 30 days or a biologic within 90 days Received any SARS-CoV-2 vaccine Received within 90 days, or is planning to receive during the study period, an immunoglobulin or blood product Received within 180 days, or is planning to receive during the study period, a biologic product with immunosuppressive properties Received for 14 days or more within 180 days, or is planning to receive during the study period, a corticosteroid Deemed ineligible for the study as determined by the principal investigator or a co-investigator