Inclusion 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***

*These criteria apply to females who are in a heterosexual relationship who are of
childbearing potential. Not of childbearing potential include post-menopausal
females (defined as having a history of amenorrhea for at least one year) or a
documented status as being surgically sterile (hysterectomy, bilateral oophorectomy,
or tubal ligation/salpingectomy).

**True abstinence is 100% of the time, no sexual intercourse (penis enters the
vagina). Periodic abstinence [e.g., calendar, ovulation, symptothermal,
post-ovulation methods] and withdrawal are not acceptable methods.

***Acceptable forms of primary contraception include a monogamous relationship with
a vasectomized partner who has been vasectomized for 180 days or more before the
participant's vaccination, intrauterine devices, birth control pills, and
injectable/implantable/insertable/transdermal hormonal birth control products. Must
have used at least one acceptable primary form of contraception for at least 30 days
before vaccination and agree to continue at least one acceptable primary form of
contraception through 60 days after vaccination.

5. Male participants must use acceptable contraception* or be vasectomized and must
refrain from donating sperm for 60 days following study vaccination.

*Acceptable contraception includes abstinence from intercourse with a female
participant of childbearing potential or use of a male condom. Contraception use
does not apply to males in an exclusively same-sex relationship.

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.

*Booster may be either homologous or heterologous to the primary vaccine series. It
must be a Food and Drug Administration (FDA)-authorized/licensed vaccine, though
doses may have been received during a clinical trial.

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.

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
/= 91 mmHg Heart rate (HR) is >/= 101
beats per minute or /= 38.0 degrees
Celsius (100.4 degrees Fahrenheit)

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.

*Significant medical or psychiatric conditions include but are not limited to
significant kidney disease, liver disease, ongoing malignancy, or recent diagnosis
of malignancy in the last five years, excluding treated basal and squamous cell
carcinoma of the skin and cervical carcinoma in situ, which are allowed.

8. Neurological or neurodevelopmental conditions*

*Including history of Bell's palsy, history of four or more migraine headaches in
the past 12 months that interfered with normal daily activity or any migraine
headache in the past 5 years that required emergency or inpatient medical care,
epilepsy, seizures in the last 5 years, encephalopathy, focal neurologic deficits,
Guillain-Barré syndrome, encephalomyelitis, transverse myelitis, stroke or transient
ischemic attack, multiple sclerosis, Parkinson's disease, amyotrophic lateral
sclerosis, Creutzfeldt-Jakob disease, or Alzheimer's disease.

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*.

*An acute illness that is nearly resolved with only minor residual symptoms
remaining is allowable if, in the opinion of the participating site Principal
Investigator or appropriate sub-investigator, the residual symptoms will not
interfere with the ability to assess safety parameters as required by the protocol.

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.**

*Chronic means more than 14 continuous days.

**Ophthalmic and topical steroids are allowed. See exclusion 19 for intranasal
steroids.

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.**

*(e.g., anaphylaxis, generalized urticaria, angioedema, other significant reaction)

**See Investigative Brochure (IB) for vaccine formulation.

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*

*Participants must have had no intranasal medication use for 30 days before study
vaccination and do not plan to use intranasal medications for 30 days after study
vaccination for medications other than steroids and for 3 months after study
vaccination for intranasal steroids (including over-the-counter (OTC) fluticasone).

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.