Inclusion Criteria:  Generally healthy male and female adults aged 18 years of age or older at the time of signing the informed consent form (i.e., 18 to 54 for Arm 1a and ≥55 for Arm 1b); Good general health as determined by screening evaluation no greater than 30 days before injection of first dose; Note: Participants who are overtly healthy as determined by medical evaluation or are considered medically stable according to the judgment of the Investigator. A stable medical condition is defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 3 months prior to enrolment, and/or hospitalization within the entire study period is not anticipated. Also, the participant appears likely to be able to remain in follow-up through the end of protocol-specified period. Mild to moderate well-controlled comorbidities are allowed. If female of child-bearing potential and heterosexually active, practice of adequate contraception for 30 days prior to injection, negative pregnancy test on the day of injection, and agreement to continue adequate contraception until 180 days after the second injection and; Written informed consent, after review of the consent form and having adequate opportunity to discuss the study with an Investigator or a qualified designee.  Exclusion Criteria:  Presence of any febrile illness or any known or suspected acute illness on the day of any immunization; Any immunodeficiency (congenital or acquired) disease, disorder, or finding that may significantly increase the risk of study participant or, in the Investigator's judgment, make the participant inappropriate for the study; Clinically significant bleeding disorder (e.g., clotting factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venipuncture; Receiving systemic immunosuppressive therapy or history of receiving chemotherapy in last 5 years other than topical agents; Receipt of systemic glucocorticoids (a dose ≥ 20 mg/day prednisone or equivalent for 14 days) within 1 month, or any other cytotoxic or immunosuppressive drug within 6 months prior to injection of first dose; Cancer diagnosis in the last 5 years, excluding basal cell and squamous cell carcinoma of the skin, which are allowed; Presence of autoimmune disease; Receipt of any investigational drug within 6 months; Receipt of any non-COVID-19 authorized vaccines within 2 weeks of receiving study dose injection; Receipt of any authorized COVID-19 vaccine prior to study enrollment; Receipt of any other experimental SARS-CoV-2/COVID-19 or other experimental coronavirus vaccine(s) at any time prior to or during the study; Receipt of blood products or immunoglobulin (IVIg or IMIg) within 3 months of study entry/baseline serologic evaluation; Current anti-tuberculosis therapy; History of any reaction or hypersensitivity likely to be exacerbated by any component of the study vaccine; Hematologic or biochemical laboratory abnormalities (blood or urine), as defined by lab normal ranges. To exclude transient abnormalities, the Investigator may repeat a test once, and if the repeat test is normal according to local reference ranges, participant may be enrolled. Grade 1 abnormalities of laboratory values will not be exclusionary if considered not clinically significant by the Investigator. And; Known current or previous laboratory-confirmed SARS-CoV-1 OR SARS-CoV-2 infection, as documented by a positive polymerase chain reaction (PCR) test from a nasal swab OR known or laboratory-confirmed positive serology.