A Study Assessing the Safety, Tolerability, Immunogenicity of COVID-19 Vaccine Candidate PRIME-2-CoV_Beta, Orf Virus Expressing SARS-CoV_2 Spike and Nucleocapsid Proteins

Inclusion Criteria:

1. Male or female participants between the ages of 18 and 55 years, (A-cohorts), and 65and 85 years (B-cohorts), inclusive at study entry.
2. Body mass index (BMI) over 19 kg/m^2 and under 32 kg/m^2 and weight at least 50 kg atstudy entry.
3. Healthy participants who are determined by medical history, physical examination, andclinical judgment of the Investigator to be eligible for inclusion in the study. Note: Healthy participants may have stable pre-existing disease defined as disease notrequiring significant change in therapy or hospitalization for worsening diseaseduring the 6 weeks before enrollment.
4. Able to give personal signed informed consent and willing and able to comply with allscheduled visits, vaccination plan, laboratory tests, and other study procedures.
5. Participants must agree not to be vaccinated with any SARS-CoV-2 vaccine, startingafter Visit 0 and continuously until 6 months after receiving the first studyimmunization.
6. Participants who have previously received at least two vaccinations with a licensedSARS-CoV-2 mRNA vaccine (Spikevax/Moderna and/or Comirnaty/Pfizer administered astwo-dose primary series with or without booster vaccination[s]) with the lastvaccination having occurred at least 3 months prior.
7. Participants who are SARS-CoV-2 vaccine-naïve (applies to vaccine-naïve group ofCohort A only):
8. Currently not working in occupations with high risk of exposure to SARS-CoV-2 (e.g., healthcare worker, emergency response personnel) (vaccine-naïve group ofCohort A only).
9. No previous vaccination with any SARS-CoV-2 vaccine (vaccine-naïve group ofCohort A only).
10. If the participant is a woman of child bearing potential (WOCBP) must:
11. have a negative beta-human chorionic gonadotropin (hCG)-urine test at Visit 0 andVisit 1.
12. agree to practice a highly effective form of contraception for at least 14 daysprior to study vaccination and continuously until a minimum of 28 days afterreceiving the last immunization.
13. agree not to donate eggs (ova, oocytes) for the purposes of assisted reproductionduring the study, starting after Visit 0 and continuously until 28 days afterreceiving the last immunization. Note: Women that are postmenopausal or permanently sterilized will be considered asnot having reproductive potential.
14. Men who are sexually active with a WOCBP and have not had a vasectomy must agree topractice a highly effective form of contraception with their female partner during thestudy, starting from Visit 1 (pre-dose) and continuously until a minimum of 28 daysafter receiving the last immunization.
15. Men must be willing to refrain from sperm donation, starting from Visit 1 (pre-dose)and continuously until a minimum of 28 days after receiving the last immunization.

Exclusion Criteria:

1. SARS-CoV-2 nucleic acid amplification test (NAAT)-positive pharyngeal swab within 24hours before receipt of study vaccine.
2. Previously NAAT-confirmed COVID-19 within the last 2 months prior to vaccination.
3. Participants who are taking medications which may prevent or treat COVID-19.
4. Participants who received convalescent serum or prior therapeutic antibodies againstSARS-CoV-2 in a period of 6 months.
5. History of severe adverse reaction associated with a vaccine and/or severe allergicreaction (e.g., anaphylaxis) to any component of the study vaccine(s).
6. Current clinical or microbiological diagnosis of COVID-19, including activerespiratory or non-respiratory symptoms associated with COVID-19 disease (i.e.symptomatic COVID-19 disease).
7. Any respiratory illness deemed clinically relevant by the investigator within the pastmonth OR hospitalization >24 hours for any reason within the past month.
8. History of or current cardiac disease, including but not limited to individuals withuncontrolled hypertension (defined as grade 1 hypertension or higher as per ISHguidelines with or without antihypertensive medication), congenital structural heartdiseases, myocarditis and/or pericarditis, coronary heart disease (with/without anginapectoris) or myocardial infarction.
9. Individuals with myocarditis after mRNA vaccination, or individuals with AEs aftermRNA-vaccination that are in nature and severity beyond the common AEs that can beexpected.
10. Individuals at high risk for severe COVID-19, including those with any of thefollowing risk factors: cancer; chronic kidney disease; chronic obstructive pulmonarydisease (COPD); immunocompromised state (weakened immune system) from solid organtransplant; rheumatologic or autoinflammatory conditions requiring immunosuppressivemedication, malignancies; obesity (BMI of 32 or higher); serious heart conditions,such as heart failure, coronary artery disease, or cardiomyopathies; sickle celldisease; insulin-dependent type 2 diabetes mellitus.
11. Anticipating the need for immunosuppressive treatment within the next 6 months.
12. Any screening hematology and/or blood chemistry laboratory value outside normal range (defined as ≥Grade 1 abnormality) and deemed clinically relevant by the investigator. Note: Except bilirubin, participants with any stable Grade 1 abnormalities may beconsidered eligible at the discretion of the Investigator.
13. Chronic immunosuppressive therapy (defined as ≥14 days), including cytotoxic agents,systemic corticosteroids exceeding 10mg/d prednisone equivalent, disease-modifyingantirheumatic drugs [DMARDs]) or any other immunomodulating agents within the last 3months or planned receipt throughout the study. Note: If systemic corticosteroids have been administered short-term (<14 days) fortreatment of an acute illness, participants should not be enrolled into the studyuntil corticosteroid therapy has been discontinued for at least 28 days before studyintervention administration. Inhaled/nebulized, intra-articular, intrabursal, ortopical (skin or eyes) corticosteroids are permitted.
14. Receipt of blood/plasma products or immunoglobulin from 60 days before study vaccineadministration or planned receipt throughout the study.
15. Immunocompromised individuals with known or suspected immunodeficiency, as determinedby history and/or laboratory/physical examination.
16. Individuals with a history of or active autoimmune disease requiring therapeuticintervention. Note: subjects with vitiligo or thyroid disease on stable dose thyroid hormonereplacement may be enrolled at the discretion of the investigator.
17. Participation in other studies involving study intervention within 28 days prior tostudy entry and/or during study participation.
18. History of human immunodeficiency virus (HIV), known seropositivity or activeinfection with HIV.
19. History of known seropositivity for or evidence of active viral infection withhepatitis B virus (HBV) or hepatitis C virus (HCV). Exception: Participants who are seropositive because of HBV vaccine are eligible.Participants who had HCV but have received an antiviral treatment and show nodetectable HCV viral deoxyribonucleic acid (DNA) for 6 months are eligible.
20. Known history of active or latent tuberculosis (bacillus tuberculosis).
21. Any concomitant serious health condition or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior, which, in the opinion ofthe Investigator, would place the participant at undue risk from the study.
22. Has received a live vaccine within 28 days of planned start of study vaccinations (i.e. 28 days before the first and after the last vaccination).
23. If a participant has contraindication to IM injections according to investigator'sassessment or received therapeutic-intensity anticoagulation for a thromboembolicevent within a period of 60 days before vaccination. Note: stable long-term prophylactic-dose anticoagulation is allowed.
24. Participants with prolonged exposure to sheep or goats (e.g., shepherds, sheepfarmer).
25. Pregnant and/or nursing women.