1. pregnant or lactating women or planning to conceive a child during the next 3 months 2. resting respiratory rate \>20 breaths/min on room air or resting pulse rate ≥ 125 beats per minute 3. a rapidly worsening course that in the opinion of the investigator or treating medical practitioner would lead to hospitalization within the next 24-48 hours 4. any chronic pulmonary disease, including chronic obstructive pulmonary disease and asthma, or other respiratory diseases that could exacerbate independent of covid-19 5. the following risk factors for severe covid-19 (cohorts 1 and 2 only) (centers for disease control 2020), which based on ongoing review of efficacy and safety data, the dmc may remove part or all of these risk factors if preliminary data show no signal for adverse or paradoxical effects: 1. severe obesity, defined as body mass index ≥ 40 kg/m2 2. history of: * severe cardiovascular disease, including but not limited to congestive heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, or pulmonary hypertension * diabetes mellitus * chronic or current vaping or cigarette smoking * chronic kidney disease requiring dialysis * chronic liver disease, including but not limited to chronic viral hepatitis, non-alcoholic steatohepatitis, or cirrhosis of any cause * hemoglobin disorder, including sickle cell disease and thalassemia 6. history of bell's palsy 7. nasal conditions that might affect the suitability of intranasal medication, such as a history of chronic rhinitis, nasal septal defect, cleft palate, nasal polyps, or nasal surgery other than cosmetic rhinoplasty. 8. use of hydroxychloroquine within the past 4 months, chloroquine with the past 9 months, or other investigational agents for covid-19 within the past 30 days 9. history of conditions associated with immunocompromise, including but not limited to poorly controlled hiv, or treatments known to affect the immune system, including but not limited to oral or intravenous corticosteroids, alkylating drugs, antimetabolites, cytotoxic drugs, radiation, immune-modulating biologics (including interleukin \[il\]-6, il-12, janus kinase inhibitors or antagonists), and cancer treatments, within 30 days of screening, or anticipated use within 6 months following participation in this study 10. 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 patient's ability to give informed consent

1. pregnant or lactating women or planning to conceive a child during the next 3 months 2. resting respiratory rate \>20 breaths/min on room air or resting pulse rate ≥ 125 beats per minute 3. a rapidly worsening course that in the opinion of the investigator or treating medical practitioner would lead to hospitalization within the next 24-48 hours 4. any chronic pulmonary disease, including chronic obstructive pulmonary disease and asthma, or other respiratory diseases that could exacerbate independent of covid-19 5. the following risk factors for severe covid-19 (cohorts 1 and 2 only) (centers for disease control 2020), which based on ongoing review of efficacy and safety data, the dmc may remove part or all of these risk factors if preliminary data show no signal for adverse or paradoxical effects: 1. severe obesity, defined as body mass index ≥ 40 kg/m2 2. history of: * severe cardiovascular disease, including but not limited to congestive heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, or pulmonary hypertension * diabetes mellitus * chronic or current vaping or cigarette smoking * chronic kidney disease requiring dialysis * chronic liver disease, including but not limited to chronic viral hepatitis, non-alcoholic steatohepatitis, or cirrhosis of any cause * hemoglobin disorder, including sickle cell disease and thalassemia 6. history of bell's palsy 7. nasal conditions that might affect the suitability of intranasal medication, such as a history of chronic rhinitis, nasal septal defect, cleft palate, nasal polyps, or nasal surgery other than cosmetic rhinoplasty. 8. use of hydroxychloroquine within the past 4 months, chloroquine with the past 9 months, or other investigational agents for covid-19 within the past 30 days 9. history of conditions associated with immunocompromise, including but not limited to poorly controlled hiv, or treatments known to affect the immune system, including but not limited to oral or intravenous corticosteroids, alkylating drugs, antimetabolites, cytotoxic drugs, radiation, immune-modulating biologics (including interleukin \[il\]-6, il-12, janus kinase inhibitors or antagonists), and cancer treatments, within 30 days of screening, or anticipated use within 6 months following participation in this study 10. 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 patient's ability to give informed consent

pregnant or lactating women or planning to conceive a child during the next 3 months resting respiratory rate >20 breaths/min on room air or resting pulse rate ≥ 125 beats per minute a rapidly worsening course that in the opinion of the investigator or treating medical practitioner would lead to hospitalization within the next 24-48 hours any chronic pulmonary disease, including chronic obstructive pulmonary disease and asthma, or other respiratory diseases that could exacerbate independent of covid-19 the following risk factors for severe covid-19 (cohorts 1 and 2 only) (centers for disease control 2020), which based on ongoing review of efficacy and safety data, the dmc may remove part or all of these risk factors if preliminary data show no signal for adverse or paradoxical effects: severe obesity, defined as body mass index ≥ 40 kg/m2 history of: severe cardiovascular disease, including but not limited to congestive heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, or pulmonary hypertension diabetes mellitus chronic or current vaping or cigarette smoking chronic kidney disease requiring dialysis chronic liver disease, including but not limited to chronic viral hepatitis, non-alcoholic steatohepatitis, or cirrhosis of any cause hemoglobin disorder, including sickle cell disease and thalassemia history of bell's palsy nasal conditions that might affect the suitability of intranasal medication, such as a history of chronic rhinitis, nasal septal defect, cleft palate, nasal polyps, or nasal surgery other than cosmetic rhinoplasty. use of hydroxychloroquine within the past 4 months, chloroquine with the past 9 months, or other investigational agents for covid-19 within the past 30 days history of conditions associated with immunocompromise, including but not limited to poorly controlled hiv, or treatments known to affect the immune system, including but not limited to oral or intravenous corticosteroids, alkylating drugs, antimetabolites, cytotoxic drugs, radiation, immune-modulating biologics (including interleukin [il]-6, il-12, janus kinase inhibitors or antagonists), and cancer treatments, within 30 days of screening, or anticipated use within 6 months following participation in this study 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 patient's ability to give informed consent

pregnant or lactating women or planning to conceive a child during the next 3 months resting respiratory rate >20 breaths/min on room air or resting pulse rate ≥ 125 beats per minute a rapidly worsening course that in the opinion of the investigator or treating medical practitioner would lead to hospitalization within the next 24-48 hours any chronic pulmonary disease, including chronic obstructive pulmonary disease and asthma, or other respiratory diseases that could exacerbate independent of covid-19 the following risk factors for severe covid-19 (cohorts 1 and 2 only) (centers for disease control 2020), which based on ongoing review of efficacy and safety data, the dmc may remove part or all of these risk factors if preliminary data show no signal for adverse or paradoxical effects: severe obesity, defined as body mass index ≥ 40 kg/m2 history of: severe cardiovascular disease, including but not limited to congestive heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, or pulmonary hypertension diabetes mellitus chronic or current vaping or cigarette smoking chronic kidney disease requiring dialysis chronic liver disease, including but not limited to chronic viral hepatitis, non-alcoholic steatohepatitis, or cirrhosis of any cause hemoglobin disorder, including sickle cell disease and thalassemia history of bell's palsy nasal conditions that might affect the suitability of intranasal medication, such as a history of chronic rhinitis, nasal septal defect, cleft palate, nasal polyps, or nasal surgery other than cosmetic rhinoplasty. use of hydroxychloroquine within the past 4 months, chloroquine with the past 9 months, or other investigational agents for covid-19 within the past 30 days history of conditions associated with immunocompromise, including but not limited to poorly controlled hiv, or treatments known to affect the immune system, including but not limited to oral or intravenous corticosteroids, alkylating drugs, antimetabolites, cytotoxic drugs, radiation, immune-modulating biologics (including interleukin [il]-6, il-12, janus kinase inhibitors or antagonists), and cancer treatments, within 30 days of screening, or anticipated use within 6 months following participation in this study 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 patient's ability to give informed consent

1. pregnant or lactating women or planning to conceive a child during the next 3 months 2. resting respiratory rate >20 breaths/min on room air or resting pulse rate ≥ 125 beats per minute 3. a rapidly worsening course that in the opinion of the investigator or treating medical practitioner would lead to hospitalization within the next 24-48 hours 4. any chronic pulmonary disease, including chronic obstructive pulmonary disease and asthma, or other respiratory diseases that could exacerbate independent of covid-19 5. the following risk factors for severe covid-19 (cohorts 1 and 2 only) (centers for disease control 2020), which based on ongoing review of efficacy and safety data, the dmc may remove part or all of these risk factors if preliminary data show no signal for adverse or paradoxical effects: 1. severe obesity, defined as body mass index ≥ 40 kg/m2 2. history of: - severe cardiovascular disease, including but not limited to congestive heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, or pulmonary hypertension - diabetes mellitus - chronic or current vaping or cigarette smoking - chronic kidney disease requiring dialysis - chronic liver disease, including but not limited to chronic viral hepatitis, non-alcoholic steatohepatitis, or cirrhosis of any cause - hemoglobin disorder, including sickle cell disease and thalassemia 6. history of bell's palsy 7. nasal conditions that might affect the suitability of intranasal medication, such as a history of chronic rhinitis, nasal septal defect, cleft palate, nasal polyps, or nasal surgery other than cosmetic rhinoplasty. 8. use of hydroxychloroquine within the past 4 months, chloroquine with the past 9 months, or other investigational agents for covid-19 within the past 30 days 9. history of conditions associated with immunocompromise, including but not limited to poorly controlled hiv, or treatments known to affect the immune system, including but not limited to oral or intravenous corticosteroids, alkylating drugs, antimetabolites, cytotoxic drugs, radiation, immune-modulating biologics (including interleukin [il]-6, il-12, janus kinase inhibitors or antagonists), and cancer treatments, within 30 days of screening, or anticipated use within 6 months following participation in this study 10. 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 patient's ability to give informed consent

1. pregnant or lactating women or planning to conceive a child during the next 3 months 2. resting respiratory rate >20 breaths/min on room air or resting pulse rate ≥ 125 beats per minute 3. a rapidly worsening course that in the opinion of the investigator or treating medical practitioner would lead to hospitalization within the next 24-48 hours 4. any chronic pulmonary disease, including chronic obstructive pulmonary disease and asthma, or other respiratory diseases that could exacerbate independent of covid-19 5. the following risk factors for severe covid-19 (cohorts 1 and 2 only) (centers for disease control 2020), which based on ongoing review of efficacy and safety data, the dmc may remove part or all of these risk factors if preliminary data show no signal for adverse or paradoxical effects: 1. severe obesity, defined as body mass index ≥ 40 kg/m2 2. history of: - severe cardiovascular disease, including but not limited to congestive heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, or pulmonary hypertension - diabetes mellitus - chronic or current vaping or cigarette smoking - chronic kidney disease requiring dialysis - chronic liver disease, including but not limited to chronic viral hepatitis, non-alcoholic steatohepatitis, or cirrhosis of any cause - hemoglobin disorder, including sickle cell disease and thalassemia 6. history of bell's palsy 7. nasal conditions that might affect the suitability of intranasal medication, such as a history of chronic rhinitis, nasal septal defect, cleft palate, nasal polyps, or nasal surgery other than cosmetic rhinoplasty. 8. use of hydroxychloroquine within the past 4 months, chloroquine with the past 9 months, or other investigational agents for covid-19 within the past 30 days 9. history of conditions associated with immunocompromise, including but not limited to poorly controlled hiv, or treatments known to affect the immune system, including but not limited to oral or intravenous corticosteroids, alkylating drugs, antimetabolites, cytotoxic drugs, radiation, immune-modulating biologics (including interleukin [il]-6, il-12, janus kinase inhibitors or antagonists), and cancer treatments, within 30 days of screening, or anticipated use within 6 months following participation in this study 10. 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 patient's ability to give informed consent