Inclusion Criteria:  Age ≥ 18 years if volunteer self-reports they are living with HIV and/or have at least one comorbidity known to be associated with severe COVID-19, for example (CDC.gov for exhaustive list):  Hypertension Type 2 diabetes mellitus Obesity (body mass index [BMI] of 30 kg/m2 or higher but < 40 kg/m2) Severe Obesity (BMI ≥ 40 kg/m2) Heart conditions, such as heart failure, coronary artery disease, or cardiomyopathies Chronic kidney disease COPD (chronic obstructive pulmonary disease) Cancer Non-HIV immunocompromised state (weakened immune system) or solid organ transplant Pregnancy Sickle cell disease Smoking Willingness to be followed and remain in the catchment area for the planned duration of the study. Ability and willingness to provide informed consent. Willingness to discuss HIV infection status, undergo related testing/monitoring labs, and receive counseling and referrals to minimize HIV acquisition/improve HIV care, as appropriate based on their infection status. Assessment of understanding: volunteer demonstrates understanding of this study; completes a questionnaire prior to first vaccination with demonstration of understanding of all questionnaire items answered incorrectly. Agrees not to enroll in another study of an investigational research agent until the end of the study. Enrollment in studies of investigational research agents for the treatment of COVID-19 is allowed for participants who develop COVID-19 disease.  Exclusion Criteria:  General  Acutely ill 72 hours prior to or at screening. Volunteers meeting this criterion may be rescheduled within the relevant window periods. Participants with minor illnesses can be enrolled at the discretion of the investigator. History of angioedema or anaphylaxis. Self-reported previous COVID-19 diagnosis.  Vaccines and other Injections  Prior receipt of a SARS-CoV-2 vaccine. History of severe allergic reaction to any ingredient of this vaccine (lipids (SM-102, polyethylene glycol [PEG] 2000 dimyristoyl glycerol [DMG], cholesterol, and 1,2-distearoyl-sn-glycero-3-phosphocholine [DSPC]), tromethamine, tromethamine hydrochloride, acetic acid, sodium acetate trihydrate, and sucrose). Live attenuated vaccines received within 30 days before first vaccination (eg, measles, mumps, and rubella [MMR]; oral polio vaccine [OPV]; varicella; yellow fever; live attenuated influenza vaccine, live attenuated zoster vaccine). Any vaccines that are not live attenuated vaccines and were received within 14 days prior to first vaccination (eg, tetanus, human papilloma virus (HPV), pneumococcal, Hepatitis A or B). Blood products, systemic immunoglobulins, or monoclonal antibodies (including against SARS-CoV-2) received within 90 days before first vaccination.