Safety, Reactogenicity, and Immunogenicity Trial of STX-S SARS-CoV-2 Vaccine in Adults

Eligibility Criteria

• 1. Provides written informed consent before initiation of any study procedures.
• 2. Able to understand and agree to comply with planned study procedures and be available for all study visits.
• 3. Non-pregnant adults, 18 through 64 years of age at the time of vaccination.
• 4. Participants of childbearing potential\* must agree to use or have practiced true abstinence\*\* or use at least one acceptable primary form of contraception\*\*\*
• 5. Male participants must use acceptable contraception\* or be vasectomized and must refrain from donating sperm for 60 days following study vaccination.
• 6. Participants of childbearing potential must have a negative urine pregnancy test at screening and within 24 hours before study vaccination.
• 7. 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 been present for at least 90 days, which would affect the assessment of the safety of participants. Chronic medical diagnoses/ conditions should be stable for the last 30 days (i.e., no hospitalizations, emergency room (ER), or urgent care for the condition). This includes no change in chronic prescription medication, dose, or frequency due to deterioration of the chronic medical diagnosis/condition 30 days before the study vaccination. Any prescription change, due to a change of health care provider, insurance company, etc., or done for financial reasons and in the same class of medication will not be considered a deviation of this inclusion criterion. Participants may be on chronic or as-needed (prn) medications if, in the opinion of the participating site Principal Investigator or appropriate sub-investigator, they pose no additional risk to participant safety or assessment of reactogenicity and immunogenicity.
• 8. Receipt of a complete primary authorized or approved COVID-19 vaccine series and at least one booster\* with the last vaccination at least 16 weeks before study vaccination.
• 9. Clinical screening laboratory evaluations are within normal reference ranges or grade 1 with no clinical significance (NCS) per the investigator's discretion.\* \*(White Blood Cells \[WBCs\] with differential, hemoglobin \[Hgb\], platelets \[PLTs\], Alanine Transaminase \[ALT\], Aspartate Transaminase \[AST\], Creatinine \[Cr\], Alkaline Phosphatase \[ALP\], Total Bilirubin \[T. Bili\]). ALT, AST, ALP, T. Bili, and creatinine values below the reference range will not be exclusionary as these values below the reference range are clinically insignificant.
• 10. Must agree to have samples stored for secondary research.
• 1. Positive SARS-CoV-2 PCR at screening.
• 2. Abnormal vital signs (Grade 1 or higher)\*:
• 3. History of SARS-CoV-2 infection or receipt of any COVID-19 vaccine \< 16 weeks prior to study vaccination.
• 4. Participant who is pregnant or breastfeeding.
• 5. Blood or plasma donation within 4 weeks before study vaccination.
• 6. Receipt of antibody or blood-derived products within 90 days before study vaccination.
• 7. Any self-reported or documented significant medical or psychiatric diseases\* or any other condition that, in the opinion of the site Principal Investigator (PI) or appropriate sub-investigator, precludes study participation.
• 8. Neurological or neurodevelopmental conditions\*
• 9. History of significant respiratory disease requiring daily medications currently, history of asthma in the past 5 years, or any treatment of respiratory disease exacerbations in the last 5 years.
• 10. History of cardiovascular disease (e.g., congestive heart failure, cardiomyopathy, ischemic heart disease), including any history of myocarditis, pericarditis, or uncontrolled cardiac arrhythmia.
• 11. Any autoimmune disease, including hypothyroidism, without a defined non-autoimmune cause.
• 12. Has an acute illness determined by the site Principal Investigator or appropriate sub-investigator within 72 hours before study vaccination\*.
• 13. 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 at screening.
• 14. Has any confirmed or suspected immunosuppressive or immunodeficient state such as asplenia, recurrent severe infections, and chronic\* immunosuppressant medication within the past 6 months.\*\*
• 15. Has received any investigational product within 60 days, or 5 half-lives, whichever is longer, before vaccination or is planning to receive one during the study.
• 16. Has a history of hypersensitivity or severe allergic reaction\* to any previous licensed or unlicensed vaccine or the candidate vaccine components.\*\*
• 17. Received or plans to receive licensed inactivated/subunit vaccine within 14 days of study vaccine administration or live vaccine within 28 days of study vaccine administration.
• 18. Plan to receive a COVID-19 booster vaccine within the 180 days following study vaccination.
• 19. Regular use of intranasal medications, including steroids\*
• 20. Use of intranasal illicit drugs in the 5 years before study vaccination or plans to use during the study.
• 21. Current smoker (including cigarettes, marijuana, and vaping) or smoking within the prior 3 months.
• 22. Planned international travel between vaccination and Day 29 visit.