COVID-19 Supplemental Vaccine Boost to Enhance T Cell Protection in Those Who Have Already Received EUA S-Based Vaccines

Inclusion Criteria:

1. Healthy adults, age ≥ 18 years, inclusive, at time of enrollment, that havepreviously received an FDA-authorized COVID-19 vaccine (both prime and boost) ≥14days and

≤ 6 months before enrollment.

2. Able to understand and provide a signed informed consent that fulfills the relevantInstitutional Review Board (IRB) or Independent Ethics Committee (IEC) guidelines.

3. Agrees to the collection of biospecimens (eg, NP swabs and/or saliva sample) andvenous blood per protocol.

4. Ability to attend required study visits and return for adequate follow-up, asrequired by this protocol.

5. Ability to swallow a capsule.

6. Temperature < 38°C.

7. Agreement to practice effective contraception for female subjects of childbearingpotential and non-sterile males. Female subjects of childbearing potential mustagree to use effective contraception while on study until at least 1 month after thelast dose of vaccine. Non-sterile male subjects must agree to use a condom while onstudy until at least 1 month after the last dose of vaccine. Effective contraceptionincludes surgical sterilization (eg, vasectomy, tubal ligation), two forms ofbarrier methods (eg, condom, diaphragm) used with spermicide, IUDs, oralcontraceptives, and abstinence.

Exclusion Criteria:

1. Persistent grade ≥ 2 AEs related to previous COVID-19 vaccination at the time ofenrollment.

2. Allergy to any component of the investigational vaccine, or a more severe allergicreaction and history of allergies in the past.

3. Pregnant and nursing women. A negative serum or urine pregnancy test duringscreening and on the day of and prior to each dose must be documented before thevaccine is administered to a female subject of childbearing potential.

4. Chronic lung disease including chronic obstructive pulmonary disease (COPD) ormoderate to severe asthma.

5. Pulmonary fibrosis.

6. Bone marrow or organ transplantation.

7. Extreme obesity (defined as BMI of 35 kg/m2 or higher).

8. Diabetes.

9. Chronic kidney disease.

10. Liver disease.

11. Sickle cell disease.

12. Thalassemia.

13. Any disease associated with acute fever, or any infection.

14. Self-reported history of SARS.

15. History of hepatitis B or hepatitis C.

16. HIV or other acquired or hereditary immunodeficiency.

17. Serious cardiovascular diseases, such as heart failure, coronary artery disease,cardiomyopathies, arrhythmia, conduction block, myocardial infarction, pulmonaryhypertension, severe hypertension without controllable drugs, etc.

18. Cerebrovascular disease.

19. Cystic fibrosis.

20. Neurologic conditions, such as dementia.

21. Hereditary or acquired angioneurotic edema.

22. No spleen or functional asplenia.

23. Platelet disorder or other bleeding disorder that may cause injectioncontraindication.

24. Chronic use (more than 14 continuous days) of any medications that may be associatedwith impaired immune responsiveness within 3 months before administration of studyvaccine. (Including, but not limited to, systemic corticosteroids exceeding 10mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon,immunomodulators. The use of low dose topical, ophthalmic, inhaled and intranasalsteroid preparations will be permitted.)

25. Prior administration of blood products in last 4 months.

26. Currently receiving treatment for cancer or history of cancer in the last five years (except basal cell carcinoma of the skin and cervical carcinoma in situ).

27. According to the judgement of investigator, various medical, psychological, socialor other conditions that could affect the subjects ability to sign informed consent.

28. Assessed by the Investigator to be unable or unwilling to comply with therequirements of the protocol.