Intranasal INNA-051 for Prevention of COVID-19 in Adults

Inclusion Criteria: 1. Capable of understanding the written informed consent, provides signed written informed consent, and agrees to comply with protocol requirements. 2. Male or female aged ≥18 years. 3. Must have a symptomatic household contact ("index case") with rapid antigen/point of-care or RT-PCR-confirmed SARS-CoV-2 infection and onset of symptoms in the household contact within 5 days prior to screening. 4. Participants of non-childbearing potential. Non-childbearing potential is defined as surgically sterile (history of bilateral tubal ligation, bilateral oophorectomy, hysterectomy, or vasectomy) or postmenopausal (amenorrhea for at least 12 months prior to screening without an alternative medical cause). Exclusion Criteria: 1. Prior exposure to INNA-051. 2. Previous receipt of any full primary series SARS-CoV-2 vaccine or receipt of a booster vaccination following a full primary series within 12 months of screening. 3. Any symptoms of COVID-19 within 72 hours prior to screening. Symptoms may include fever (≥38°C), cough, sore throat, malaise, headache, muscle pain, nausea, vomiting, diarrhea, loss of taste and/or smell, shortness of breath, or difficulty breathing. 4. History of RT-PCR-confirmed SARS-CoV-2 infection within 6 months prior to screening. 5. Positive point-of-care rapid SARS-CoV-2 diagnostic test at the time of screening. 6. Body mass index ≥35 kg/m2. 7. History of human immunodeficiency virus, current chronic hepatitis B virus or hepatitis C virus infection or current tuberculosis. 8. History of chronic kidney disease (Stage 3 or higher). 9. Chronic lung disease (chronic obstructive pulmonary disease, moderate-to-severe poorly controlled asthma \[as evident within the last month of awakening with asthma symptoms 1 or more times/week or use of short-acting beta-agonists 3 or more times/week\], interstitial lung disease, cystic fibrosis, pulmonary hypertension). 10. History of significant cardiovascular disease (e.g., congestive heart failure, cardiomyopathy, ischemic heart disease) or history of myocarditis or pericarditis. 11. Current uncontrolled hypertension defined as average of 3 systolic blood pressure readings of ≥140 mmHg or an average of 3 diastolic blood pressure ≥90 mmHg. 12. History of chronic liver disease or documented evidence of liver fibrosis or cirrhosis. 13. History of hemoglobinopathy (sickle cell disease, thalassemia). 14. Chronic use of inhaled substances including tobacco, nicotine vapor, or cannabis (average of ≥5 cigarettes a day for ≥1 month within 1 year of screening or a 10 pack year history or equivalent). 15. History of neurological or neurodevelopmental conditions (e.g., Down's syndrome, dementia, migraine, epilepsy, stroke, seizure in the last 3 years, encephalopathy, focal neurologic deficits, Guillain-Barré syndrome, encephalomyelitis, or transverse myelitis). 16. History of malignancy in the last 5 years, except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer. 17. History of immunodeficiency or chronic use (more than 14 continuous days) of any medication that may be associated with changes in the immune function including, but not limited to, systemic corticosteroids exceeding 10 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar or toxic drugs within 6 months of screening. Note: The use of low-dose topical and ophthalmic steroid preparations is permitted. 18. Use of nasal sprays (including but not limited to nasal glucocorticoids), intranasal washes, or other intranasal applications within 7 days prior to screening, or planned use during the study period. 19. Known allergy or sensitivity or contraindication to study drug or its excipients. 20. Treatment with any other investigational therapy or device within 30 days or within 5 half-lives, whichever is longer, prior to screening. 21. Female participants who are pregnant or trying to become pregnant, or who are breastfeeding. 22. Known history of substance abuse that in the investigator's judgment would prevent participant from providing informed consent or being able to comply with study procedures. 23. Other severe, acute, or chronic medical or psychiatric condition(s) that may increase the risk associated with study participation or interfere with the participant's ability to comply with study procedures