Safety and Immunogenicity Trial of MPV/S-2P SARS-CoV-2 Vaccine in Adults

Inclusion Criteria:

1. Provides written informed consent prior to initiation of any study procedures.

2. Able to understand and agrees to comply with planned study procedures and beavailable for all study visits.

3. Non-pregnant adults, 18-64 years of age at time of vaccination.

4. Participants of childbearing potential * must agree to use or have practiced trueabstinence ** or use at least one acceptable primary form of contraception *** *These criteria are applicable to persons assigned female at birth who have sexualintercourse with a person assigned male at birth, and who are of childbearingpotential. Not of childbearing potential include post-menopausal females (defined ashaving a history of amenorrhea for at least one year) or a documented status asbeing surgically sterile (hysterectomy, bilateral oophorectomy, tuballigation/salpingectomy, or Essure (R) placement) ** True abstinence is 100 percentof time no sexual intercourse (penis enters the vagina). Periodic abstinence [e.g.,calendar, ovulation, symptothermal, post-ovulation methods] and withdrawal are notacceptable methods.

*** Acceptable forms of primary contraception include monogamous relationship with avasectomized partner who has been vasectomized for 180 days or more prior to theparticipant's vaccination, intrauterine devices, birth control pills, andinjectable/implantable/insertable/transdermal hormonal birth control products. Musthave used at least one acceptable primary form of contraception for at least 30 daysprior to vaccination and agree to continue at least one acceptable primary form ofcontraception through 60 days after vaccination

5. Participants of childbearing potential must have a negative urine pregnancy test atscreening and within 24 hours prior to study vaccination.

6. In general good health*.

*As determined by medical history and physical examination, including vital signs,to evaluate acute or ongoing chronic medical diagnoses/conditions that have beenpresent for at least 90 days, which would affect the assessment of safety ofparticipants. Chronic medical diagnoses/ conditions should be stable for the last 30days (i.e., no hospitalizations, ER, or urgent care for condition). This includes nochange in chronic prescription medication, dose, or frequency as a result ofdeterioration of the chronic medical diagnosis/condition in the 30 days before studyvaccination. Any prescription change that is due to change of health care provider,insurance company, etc., or done for financial reasons, and in the same class ofmedication, will not be considered a deviation of this inclusion criterion.Participants may be on chronic or as needed (prn) medications if, in the opinion ofthe participating site PI or appropriate sub-investigator, they pose no additionalrisk to participant safety or assessment of reactogenicity and immunogenicity.

7. Receipt of a complete primary COVID-19 mRNA vaccine series and at least one mRNAbooster* with last vaccination at least 16 weeks prior to study vaccination.

• Booster may be either homologous or heterologous to the primary vaccine seriesand must be an FDA authorized/licensed mRNA vaccine though doses may have beenreceived as part of a clinical trial.

8. Clinical screening laboratory evaluations are within normal reference ranges orgrade 1 with no clinical significance (NCS) per investigator discretion*.

*White Blood Cells [WBCs] with differential, hemoglobin [Hgb], platelets [PLTs],Alanine Transaminase [ALT], Aspartate Transaminase [AST], Creatinine [Cr], AlkalinePhosphatase [ALP], Total Bilirubin [T. Bili]). ALT, AST, ALP, T. Bili and creatininevalues that are below the reference range will not be exclusionary as these valuesbelow reference range are clinically insignificant.

9. Must agree to have samples stored for secondary research.

10. Must agree to wearing a surgical mask (or KN-95 or N-95) within 6 feet of others for 14 days after study vaccination, and potentially longer if asked by study team basedon data gathered.

Exclusion Criteria:

1. Positive SARS-CoV-2 PCR at screening.

2. Abnormal vital signs (Grade 1 or higher)*

*Grade 1 or higher is equivalent to: Systolic blood pressure (SBP) >/= 141 mmHg or </= 89 mmHg Diastolic blood pressure (DBP) >/= 91 mmHg Heart rate (HR) is >/= 101beats per minute or </= 54 beats per minute Oral temperature >/= 38.0°C (100.4°F)

3. History of SARS-CoV-2 infection or receipt of any COVID-19 vaccine < 16 weeks priorto study vaccination.

4. Participant who is pregnant or breastfeeding.

5. Blood or plasma donation within 4 weeks prior to study vaccination.

6. Receipt of antibody or blood-derived products within 90 days prior to studyvaccination.

7. Any self-reported or documented significant medical or psychiatric diseases* or anyother condition that, in the opinion of the site PI or appropriate sub-investigator,precludes study participation.

*Significant medical or psychiatric conditions include but are not limited torespiratory disease (e.g., chronic obstructive pulmonary disease [COPD]) requiringdaily medications currently, history of asthma in the past 5 years, or any treatmentof respiratory disease exacerbations in the last 5 years. Significant kidneydisease, liver disease, or cardiovascular disease (e.g., congestive heart failure,cardiomyopathy, ischemic heart disease), including any history of myocarditis orpericarditis, or uncontrolled cardiac arrhythmia. Neurological or neurodevelopmentalconditions (e.g., history of Bell's palsy, history of four or more migraineheadaches in the past 12 months that interfered with normal daily activity or anymigraine headache in the past 5 years that required emergency or inpatient medicalcare, epilepsy, seizures in the last 5 years, encephalopathy, focal neurologicdeficits, Guillain-Barré syndrome, encephalomyelitis, transverse myelitis, stroke ortransient ischemic attack, multiple sclerosis, Parkinson's disease, amyotrophiclateral sclerosis, Creutzfeldt-Jakob disease, or Alzheimer's disease). Ongoingmalignancy or recent diagnosis of malignancy in the last five years excludingtreated basal cell and squamous cell carcinoma of the skin, which are allowed. Anyautoimmune disease, including hypothyroidism without a defined non-autoimmune cause.

8. Any significant nasal or upper airway disease*.

*(Including, but not limited to, being prone to epistaxis, a history of inflammatoryrhinitis (including allergic rhinitis) that requires daily medications, cochlearimplants, head/neck radiation history, anosmia/dysosmia, conditions that requireprescription or over the counter intranasal medication (intermittent use will beallowed if no use occurred for 30 days before study vaccination and participantagrees to not use intranasal medication (other than steroids) for 30 days afterstudy vaccination and to not use intranasal steroids for 6 months after studyvaccination), and certain ear, nose and throat (ENT) conditions, includingsignificant upper airway/nasopharyngeal disease or abnormal anatomy such as CSFleak.

9. Has an acute illness, as determined by the site PI or appropriate sub-investigatorwithin 72 hours prior to study vaccination*.

*An acute illness which is nearly resolved with only minor residual symptomsremaining is allowable if, in the opinion of the participating site PI orappropriate sub-investigator, the residual symptoms will not interfere with theability to assess safety parameters as required by the protocol.

10. Has a positive test result for hepatitis B surface antigen, hepatitis C virus RNA (by reflex testing), or human immunodeficiency virus (HIV) antigen/antibody test atscreening.

11. Has any confirmed or suspected immunosuppressive or immunodeficient state such asasplenia, recurrent severe infections and chronic* immunosuppressant medicationwithin the past 6 months**.

*Chronic meaning more than 14 continuous days.

**Ophthalmic and topical steroids are allowed, see exclusion 19 for intranasalsteroids.

12. Has received any investigational product within 60 days, or 5 half-lives, whicheveris longer, before vaccination; or is planning to receive one during the study.

13. Has a history of hypersensitivity or severe allergic reaction* to any previouslicensed or unlicensed vaccine or to the candidate vaccine components.

• (e.g., anaphylaxis, generalized urticaria, angioedema, other significantreaction)

• See section 6.5.1 for vaccination formulation

14. Resides in or works in a nursing home or other skilled nursing facility.

15. Resides with or cares for immunocompromised persons, pregnant individuals, orchildren under 2 years of age (inclusive of health care workers and others withpatient contact in health care settings).

16. People who handle rodents (laboratory workers, vivarium workers, pet store workers,etc.) or keep rodents as pets.

17. Received or plans to receive licensed inactivated/subunit vaccine within 14 days ofstudy vaccine administration or live vaccine within 28 days of study vaccineadministration.

18. Plan to receive a COVID-19 booster vaccine within the 180 days following studyvaccination.

19. Regular use of intranasal medications including steroids*.

*Participant must have had no intranasal medication use for 30 days prior to studyvaccination and plans not to use intranasal medications for 30 days after studyvaccination for medications other than steroids, and for 6 months after studyvaccination for intranasal steroids (including over-the-counter Flonase).

20. Use of intranasal illicit drugs in the 5 years prior to study vaccination or plansto use during the study.

21. Planned international travel between vaccination and Day 29 visit.

22. Current smoker (including cigarettes, marijuana, and vaping) or smoking within 3months.