Study in Adults to Assess the Safety and Efficacy of Inhaled IBIO123, for Post-exposure Prophylaxis of COVID-19

Inclusion Criteria: 1. Are ≥18 years of age at the time of randomization 2. Subject has a household contact with a confirmed COVID-19 cohabiting individual as subject. Initial diagnosis of the COVID-19 positive individual has been within 3 days of screening. COVID-19 positive result (PCR or Antigen) must have been performed by an accredited lab or medical professional. Current and uninterrupted household contacts were defined as family members or close relatives who had unprotected contact with the index case. 3. Subject must have a negative result with the study provided rapid antigen test at baseline and be COVID-19 symptom free. 4. Are men or non-pregnant women. Reproductive and Contraceptive agreements and guidance is provided in Appendix 2. Contraceptive use by men or women should be consistent with local regulations for those participating in clinical studies. 5. Understand and agree to comply with planned study procedures 6. Agree to the collection of nasopharyngeal swabs 7. The participant or legally authorized representative gives signed informed consent as described in Section 10.1.1.2 which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol. Exclusion Criteria: 1. A positive COVID-19 result (PCR or antigen test) within 30 days of screening. 2. Presence of typical COVID-19 symptoms which cannot be explained by another underlying condition (fever \>38°C, Oxygen saturation (SpO2) below 93%, dyspnea, difficulty breathing, chills, ageusia, anosmia, cough, myalgia) in the past 48 hours prior to screening. 3. Hypersensitivity to any component of IBIO123 4. Participants who have been previously administered IBIO123. 5. Have received treatment with a SARS-CoV-2 specific monoclonal antibody 6. Have participated, within the last 30 days, in a clinical study involving an investigational intervention. If the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed. 7. Are pregnant or breast feeding 8. Are investigator site personnel directly affiliated with this study.