A Study to Evaluate VXA-CoV2-3.1 COVID-19 Vaccine Against Currently Approved/Authorized mRNA COVID-19 Injectable Booster Vaccine in Adults Previously Immunized Against COVID-19 Infection

Inclusion Criteria:

1. Adults 18 years of age and above, at time of screening.

2. Completed primary approved/authorized COVID-19 vaccination series with ≥ 2 mRNAvaccine doses.

3. Last COVID-19 vaccine received ≥6 months prior to study vaccination.

4. Male and female participants of childbearing potential must agree to consistentlyuse a highly effective method of contraception from at least 30 days prior toenrollment and through 3 months after the last study vaccination.

5. Is medically stable, as determined by the site investigator (based on review ofhealth status, vital signs, medical history, and physical examination) withscreening lab values within normal limits or abnormalities assessed as notclinically significant.

6. Agree to not participate in any other SARS-CoV-2 infection prevention trial (vaccine, drug, biologic, PrEP) during participation in the study.

7. Willing and able to provide informed consent prior to initiation of studyprocedures.

8. Available for all study visits, willing to participate in all study procedures, andnot planning to relocate from the area for the duration of the study.

9. Negative rapid molecular Covid test at the screening visit and on Day 1 prior tovaccine dosing.

Exclusion Criteria:

1. Participant has an acute illness as defined by any of the following (note:assessment may be repeated once during screening period): a. As determined by the site investigator, within 72 hours prior to vaccination. i. An acute illness that is nearly resolved, with only minor residual symptomsremaining, is allowable if, in the opinion of the site investigator, the residualsymptoms will not interfere with the ability of study staff to assess safetyparameters as required by the protocol. b. Presence of a fever ≥ 38.0°C (100.4°F)measured orally at baseline, on Day 1 prior to vaccination. c. Receipt ofantipyretic/analgesic medications within 24 hours prior to vaccine administration.

2. Participant has had a positive COVID test within 90 days prior to screening.

3. Current or planned participation in any other interventional clinical trial.

4. Participation in research involving any investigational product within 45 days priorto study vaccination.

5. Receipt of any approved or authorized products intended to prevent SARS-CoV2infection within 6 months prior to study vaccination.

6. Receipt or donation of blood products or immunoglobulins within 60 days prior toenrollment or planned administration during the study.

7. Received influenza vaccination within 14 days prior to study vaccination, or anyother vaccine within 30 days prior to study vaccination.

8. Any autoimmune or immunodeficiency disease/condition (including and not limited tountreated or advanced HIV infection with CD4 counts <200 cells/mm^3, history of AIDSdefining illness without immune reconstitution, or clinical manifestations ofsymptomatic HIV, severe combined immunodeficiency (SCID), hypogammaglobulinemia,asplenia or functional asplenia).

9. Unstable medical or psychiatric illness (acute or chronic illness) requiringsignificant medical monitoring and intervention during the 90 days prior toenrollment. Note: diabetes mellitus (Types 1 & 2) are not excluded if assessed bythe principal investigator (PI) as well-controlled.

10. Administration of immunosuppressants, systemic glucocorticoids, or otherimmune-modifying drugs within the following timeframes:

11. B-cell therapies within the 6 months prior to first study vaccination

12. Prednisone, ≥20 mg for more than 2 weeks, within the 30 days prior to studyvaccination

13. Other medications in this category, including but not limited to high-doseinhaled corticosteroids (>800 mcg/day of beclomethasone dipropionate orequivalent); antimetabolites; transplant immunosuppressive agents; alkylatingagents; cell-depleting agents; or cancer chemotherapeutics, within the 90 daysprior to study vaccination.

14. Any medication for any period of time that, in the opinion of the siteinvestigator, could impede immune response to vaccination.

15. Use of any dose montelukast OR inhaled, intranasal, intra-articular, orsystemic corticosteroids within 2 weeks prior to study vaccination.

16. Planned use of any of these medications during the study.

17. Known contraindication to IM injection or blood draws (e.g. bleeding diathesis,acquired coagulopathy, significant bleeding or bruising) or to oral route ofadministration (unable to swallow tablets).

18. Any known allergies to components contained in the investigational product (including fish gelatin) or comparator or latex allergy (including polyethyleneglycol [PEG] allergies) and/or history of serious reactions to vaccination such asanaphylaxis, respiratory problems, hives, or abdominal pain.

19. Women who are pregnant (pregnancy tests will be performed at screening and prior todosing), breastfeeding, or who plan to become pregnant during the study.

20. History of irritable bowel disease or other inflammatory digestive orgastrointestinal condition that could affect the distribution/safety evaluation ofan orally administered vaccine targeting the mucosa of the small intestine. Suchconditions may include but are not limited to: a. Any history of: i. GI malignancy ii. malabsorption iii. pancreatobiliarydisorders iv. inflammatory bowel disease v. irritable bowel disease vi. hiatalhernia vii. surgical resection b. History of diagnosis or treatment in past 5 yearsof: i. esophageal or gastric motility disorder ii. gastroesophageal reflux disorderiii. peptic ulcer iv. cholecystectomy.

21. Use of antibiotics, proton pump inhibitors, H2 blockers, or antacids within 7 daysprior to study drug administration or planned use during the study.

22. Use of drugs known to affect gastrointestinal motility including glucagon-likepeptide 1 (GLP-1) receptor agonists including tirzepatide (Mounjaro) and semaglutide (Wegovy, Ozempic) within 30 days prior to drug administration.

23. Daily use of nonsteroidal anti-inflammatory drugs within 7 days prior to study drugadministration or planned use during the study.

24. Personal or familial history of hypercoagulable states to include personal pasthistory of deep vein thrombosis (DVT).

25. Personal history of myocarditis or pericarditis.

26. Positive Hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) antibody atthe screening visit.

27. History of drug, alcohol, or chemical abuse within 1 year of screening.

28. Positive urine drug screen for drugs of abuse at screening (except for previousmarijuana use); concurrent or planned use of marijuana during the active studyperiod are excluded. Positive urine drug screen (UDS) at screening due to prescribedstimulants will be reviewed on a case by case basis.

29. Cancer, or treatment for cancer, within the past 3 years (excluding fully treatedand resolved basal cell carcinoma or squamous cell carcinoma).

30. History of any form of angioedema.

31. History of GI bleeding including hematochezia (blood in stool) or melena (blackstool) of unknown etiology or that has not been evaluated.

32. Any history or conditions that may lead to a higher risk of clotting events and/orthrombocytopenia, including:

33. Familial coagulopathy or personal history of bleeding disorder or thrombosis

34. History of heparin-related thrombotic events, and/or receiving heparintreatments

35. History of autoimmune or inflammatory disease

36. Presence of any of the following conditions known to increase the risk ofthrombosis within 6 months prior to screening: i. Recent surgery other than fully healed cesarean delivery or excision/ biopsy ofcutaneous lesions ii. Immobility (confined to bed or wheelchair for 3 or moresuccessive days) iii. Head trauma with loss of consciousness or documented braininjury iv. Receipt of anticoagulants for prophylaxis of thrombosis v. Recentclinically significant infection including hospitalization for COVID-19 relatedillness.

37. Any other condition that, in the opinion of the investigator, would pose a healthrisk to the participant if enrolled or could interfere with evaluation of theinvestigational product or interpretation of study results.

38. Study team member or first-degree relative of any study team member (inclusive ofsponsor and site personnel involved in the study).