Patient Inclusion Criteria

- Men and women ages 18 to 55 years, inclusive - Good general health status - Screening laboratory results within institutional normal range or Grade 1 abnormality if the Investigator documents clinical insignificance. Grade 2 laboratories may be permissible if considered not clinically significant by the investigator. - For women who have not been surgically sterilized or who do not have laboratory confirmation of postmenopausal status, negative pregnancy test - Willingness to practice a highly effective method of contraception - Ability and willingness to comply with all aspects of the study, including nasopharyngeal swabs and blood and urine samples, through the entire study period

Patient Exclusion Criteria

- Subjects at increased risk of exposure to SARS-CoV-2, including healthcare workers, emergency response personnel, and those with known contact with COVID-19 patients - Pregnant or lactating women or planning to conceive a child during the next 3 months - Body mass index (BMI) > 30.0 kg/m2 - Acute COVID-19, a positive test result for SARS-CoV2 infection, a positive SARS-CoV-2 serology for prior SARS-CoV-2 infection at screening, or exposure within 14 days to an individual with acute COVID-19 - An acute respiratory illness - Positive result for HIV, hepatitis B virus, or hepatitis C virus at screening - Chronic or current cigarette smoking - Any medical, psychiatric, or social condition or occupational or other responsibility that in the judgment of the Investigator would interfere with or serve as a contraindication to protocol adherence, assessment of safety (including reactogenicity), or a subject's ability to give informed consent