1. receipt of approved or authorized covid vaccine \< 150 days prior to planned study vaccine administration or planned receipt of covid vaccine during 6 months following receipt of study vaccine. 2. covid infection (positive covid-19 test) \< 150 days prior to planned study vaccine administration 3. pregnant or breastfeeding participants. 4. history of severe covid-19 infection (e.g., need for oxygenation or ventilatory support) 5. receipt of sars-cov-2 immunoglobulin, monoclonal antibody or plasma antibody therapy \< 150 days prior to study vaccine administration 6. any prior receipt of a piv5-based vaccine (e.g., cvxga1 or blb-201 \[an rsv vaccine being developed by blue lake biotechnology\]). 7. chronic rhinitis, nasal septal defect causing significant breathing problems, cleft palate, nasal polyps, or other nasal abnormality that might affect vaccine administration. 8. current or planned simultaneous participation in another interventional study or receipt of any investigational study product within 28 days prior to study vaccine administration 9. a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine (licensed or unlicensed). 10. a history of myocarditis or pericarditis at any time prior to enrollment, history of kawasaki disease, or history of multisystem inflammatory syndrome after covid infection. 11. received or plans to receive a vaccine within 14 days prior to or after study vaccine. 12. bleeding disorder diagnosed by a healthcare provider (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or bleeding difficulties with intramuscular injections or blood draws. 13. current or previous diagnosis of a significant immunocompromising condition or other immunosuppressive condition. 14. resides with someone who is severely immunocompromised. 15. advanced liver or kidney diseases. 16. advanced (cd4 count \< 200) and/or untreated hiv, active hepatitis b virus infection, positive serology for hepatitis c. 17. received oral, intramuscular or intravenous systemic immunosuppressants, or immune-modifying drugs for \>14 days in total within 6 months prior to administration of study vaccine (for corticosteroids \> / = 20 mg/day of prednisone equivalent). 18. history of significant/severe wheeze, respiratory symptoms resulting in hospitalization, or known bronchial hyperreactivity to viruses. 19. received immunoglobulin or blood-derived products, within 3 months prior to study vaccine dose. 20. received chemotherapy, immunotherapy or radiation therapy within 6 months prior to study vaccine dose. 21. study personnel or an immediate family member or household member of study personnel. 22. is acutely ill or febrile 72 hours prior to or at vaccine dosing day (fever defined as \> / = 38.0 degrees celsius /100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. 23. receipt or anticipated receipt of, within 7 days prior to through 28 days after trial vaccination, any intranasal medication including fda-approved prescription or over-the-counter products or non-fda-approved alternative medicine products (e.g., ayurvedic oil or other naturopathic substances). 24. currently smoking or vaping, or history of regular smoking or vaping in the past two years 25. active alcohol use disorder or alcohol abuse or active illicit drug abuse 26. anticipated use of nasal irrigation (e.g., neti pot™) after enrollment through 28 days after trial vaccination. 27. diagnosis of dementia or other cognitive deficit that might impact a participant's ability to understand the clinical trial or be compliant with trial procedures. 28. planned hospital admission (e.g., for surgical or other invasive procedures) during the 6 months after trial enrollment that could interfere with study trial visits. 29. planned admission or stay at an assisted living or other care facility during the 6 months after trial enrollment.

1. receipt of approved or authorized covid vaccine \< 150 days prior to planned study vaccine administration or planned receipt of covid vaccine during 6 months following receipt of study vaccine. 2. covid infection (positive covid-19 test) \< 150 days prior to planned study vaccine administration 3. pregnant or breastfeeding participants. 4. history of severe covid-19 infection (e.g., need for oxygenation or ventilatory support) 5. receipt of sars-cov-2 immunoglobulin, monoclonal antibody or plasma antibody therapy \< 150 days prior to study vaccine administration 6. any prior receipt of a piv5-based vaccine (e.g., cvxga1 or blb-201 \[an rsv vaccine being developed by blue lake biotechnology\]). 7. chronic rhinitis, nasal septal defect causing significant breathing problems, cleft palate, nasal polyps, or other nasal abnormality that might affect vaccine administration. 8. current or planned simultaneous participation in another interventional study or receipt of any investigational study product within 28 days prior to study vaccine administration 9. a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine (licensed or unlicensed). 10. a history of myocarditis or pericarditis at any time prior to enrollment, history of kawasaki disease, or history of multisystem inflammatory syndrome after covid infection. 11. received or plans to receive a vaccine within 14 days prior to or after study vaccine. 12. bleeding disorder diagnosed by a healthcare provider (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or bleeding difficulties with intramuscular injections or blood draws. 13. current or previous diagnosis of a significant immunocompromising condition or other immunosuppressive condition. 14. resides with someone who is severely immunocompromised. 15. advanced liver or kidney diseases. 16. advanced (cd4 count \< 200) and/or untreated hiv, active hepatitis b virus infection, positive serology for hepatitis c. 17. received oral, intramuscular or intravenous systemic immunosuppressants, or immune-modifying drugs for \>14 days in total within 6 months prior to administration of study vaccine (for corticosteroids \> / = 20 mg/day of prednisone equivalent). 18. history of significant/severe wheeze, respiratory symptoms resulting in hospitalization, or known bronchial hyperreactivity to viruses. 19. received immunoglobulin or blood-derived products, within 3 months prior to study vaccine dose. 20. received chemotherapy, immunotherapy or radiation therapy within 6 months prior to study vaccine dose. 21. study personnel or an immediate family member or household member of study personnel. 22. is acutely ill or febrile 72 hours prior to or at vaccine dosing day (fever defined as \> / = 38.0 degrees celsius /100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. 23. receipt or anticipated receipt of, within 7 days prior to through 28 days after trial vaccination, any intranasal medication including fda-approved prescription or over-the-counter products or non-fda-approved alternative medicine products (e.g., ayurvedic oil or other naturopathic substances). 24. currently smoking or vaping, or history of regular smoking or vaping in the past two years 25. active alcohol use disorder or alcohol abuse or active illicit drug abuse 26. anticipated use of nasal irrigation (e.g., neti pot™) after enrollment through 28 days after trial vaccination. 27. diagnosis of dementia or other cognitive deficit that might impact a participant's ability to understand the clinical trial or be compliant with trial procedures. 28. planned hospital admission (e.g., for surgical or other invasive procedures) during the 6 months after trial enrollment that could interfere with study trial visits. 29. planned admission or stay at an assisted living or other care facility during the 6 months after trial enrollment.

receipt of approved or authorized covid vaccine < 150 days prior to planned study vaccine administration or planned receipt of covid vaccine during 6 months following receipt of study vaccine. covid infection (positive covid-19 test) < 150 days prior to planned study vaccine administration pregnant or breastfeeding participants. history of severe covid-19 infection (e.g., need for oxygenation or ventilatory support) receipt of sars-cov-2 immunoglobulin, monoclonal antibody or plasma antibody therapy < 150 days prior to study vaccine administration any prior receipt of a piv5-based vaccine (e.g., cvxga1 or blb-201 [an rsv vaccine being developed by blue lake biotechnology]). chronic rhinitis, nasal septal defect causing significant breathing problems, cleft palate, nasal polyps, or other nasal abnormality that might affect vaccine administration. current or planned simultaneous participation in another interventional study or receipt of any investigational study product within 28 days prior to study vaccine administration a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine (licensed or unlicensed). a history of myocarditis or pericarditis at any time prior to enrollment, history of kawasaki disease, or history of multisystem inflammatory syndrome after covid infection. received or plans to receive a vaccine within 14 days prior to or after study vaccine. bleeding disorder diagnosed by a healthcare provider (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or bleeding difficulties with intramuscular injections or blood draws. current or previous diagnosis of a significant immunocompromising condition or other immunosuppressive condition. resides with someone who is severely immunocompromised. advanced liver or kidney diseases. advanced (cd4 count < 200) and/or untreated hiv, active hepatitis b virus infection, positive serology for hepatitis c. received oral, intramuscular or intravenous systemic immunosuppressants, or immune-modifying drugs for >14 days in total within 6 months prior to administration of study vaccine (for corticosteroids > / = 20 mg/day of prednisone equivalent). history of significant/severe wheeze, respiratory symptoms resulting in hospitalization, or known bronchial hyperreactivity to viruses. received immunoglobulin or blood-derived products, within 3 months prior to study vaccine dose. received chemotherapy, immunotherapy or radiation therapy within 6 months prior to study vaccine dose. study personnel or an immediate family member or household member of study personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing day (fever defined as > / = 38.0 degrees celsius /100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. receipt or anticipated receipt of, within 7 days prior to through 28 days after trial vaccination, any intranasal medication including fda-approved prescription or over-the-counter products or non-fda-approved alternative medicine products (e.g., ayurvedic oil or other naturopathic substances). currently smoking or vaping, or history of regular smoking or vaping in the past two years active alcohol use disorder or alcohol abuse or active illicit drug abuse anticipated use of nasal irrigation (e.g., neti pot™) after enrollment through 28 days after trial vaccination. diagnosis of dementia or other cognitive deficit that might impact a participant's ability to understand the clinical trial or be compliant with trial procedures. planned hospital admission (e.g., for surgical or other invasive procedures) during the 6 months after trial enrollment that could interfere with study trial visits. planned admission or stay at an assisted living or other care facility during the 6 months after trial enrollment.

receipt of approved or authorized covid vaccine < 150 days prior to planned study vaccine administration or planned receipt of covid vaccine during 6 months following receipt of study vaccine. covid infection (positive covid-19 test) < 150 days prior to planned study vaccine administration pregnant or breastfeeding participants. history of severe covid-19 infection (e.g., need for oxygenation or ventilatory support) receipt of sars-cov-2 immunoglobulin, monoclonal antibody or plasma antibody therapy < 150 days prior to study vaccine administration any prior receipt of a piv5-based vaccine (e.g., cvxga1 or blb-201 [an rsv vaccine being developed by blue lake biotechnology]). chronic rhinitis, nasal septal defect causing significant breathing problems, cleft palate, nasal polyps, or other nasal abnormality that might affect vaccine administration. current or planned simultaneous participation in another interventional study or receipt of any investigational study product within 28 days prior to study vaccine administration a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine (licensed or unlicensed). a history of myocarditis or pericarditis at any time prior to enrollment, history of kawasaki disease, or history of multisystem inflammatory syndrome after covid infection. received or plans to receive a vaccine within 14 days prior to or after study vaccine. bleeding disorder diagnosed by a healthcare provider (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or bleeding difficulties with intramuscular injections or blood draws. current or previous diagnosis of a significant immunocompromising condition or other immunosuppressive condition. resides with someone who is severely immunocompromised. advanced liver or kidney diseases. advanced (cd4 count < 200) and/or untreated hiv, active hepatitis b virus infection, positive serology for hepatitis c. received oral, intramuscular or intravenous systemic immunosuppressants, or immune-modifying drugs for >14 days in total within 6 months prior to administration of study vaccine (for corticosteroids > / = 20 mg/day of prednisone equivalent). history of significant/severe wheeze, respiratory symptoms resulting in hospitalization, or known bronchial hyperreactivity to viruses. received immunoglobulin or blood-derived products, within 3 months prior to study vaccine dose. received chemotherapy, immunotherapy or radiation therapy within 6 months prior to study vaccine dose. study personnel or an immediate family member or household member of study personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing day (fever defined as > / = 38.0 degrees celsius /100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. receipt or anticipated receipt of, within 7 days prior to through 28 days after trial vaccination, any intranasal medication including fda-approved prescription or over-the-counter products or non-fda-approved alternative medicine products (e.g., ayurvedic oil or other naturopathic substances). currently smoking or vaping, or history of regular smoking or vaping in the past two years active alcohol use disorder or alcohol abuse or active illicit drug abuse anticipated use of nasal irrigation (e.g., neti pot™) after enrollment through 28 days after trial vaccination. diagnosis of dementia or other cognitive deficit that might impact a participant's ability to understand the clinical trial or be compliant with trial procedures. planned hospital admission (e.g., for surgical or other invasive procedures) during the 6 months after trial enrollment that could interfere with study trial visits. planned admission or stay at an assisted living or other care facility during the 6 months after trial enrollment.

receipt of approved or authorized covid vaccine < 150 days prior to planned study vaccine administration or planned receipt of covid vaccine during 6 months following receipt of study vaccine. covid infection (positive covid-19 test) < 150 days prior to planned study vaccine administration pregnant or breastfeeding participants. history of severe covid-19 infection (e.g., need for oxygenation or ventilatory support) receipt of sars-cov-2 immunoglobulin, monoclonal antibody or plasma antibody therapy < 150 days prior to study vaccine administration any prior receipt of a piv5-based vaccine (e.g., cvxga1 or blb-201 [an rsv vaccine being developed by blue lake biotechnology]). chronic rhinitis, nasal septal defect causing significant breathing problems, cleft palate, nasal polyps, or other nasal abnormality that might affect vaccine administration. current or planned simultaneous participation in another interventional study or receipt of any investigational study product within 28 days prior to study vaccine administration a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine (licensed or unlicensed). a history of myocarditis or pericarditis at any time prior to enrollment, history of kawasaki disease, or history of multisystem inflammatory syndrome after covid infection. received or plans to receive a vaccine within 14 days prior to or after study vaccine. bleeding disorder diagnosed by a healthcare provider (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or bleeding difficulties with intramuscular injections or blood draws. current or previous diagnosis of a significant immunocompromising condition or other immunosuppressive condition. resides with someone who is severely immunocompromised. advanced liver or kidney diseases. advanced (cd4 count < 200) and/or untreated hiv, active hepatitis b virus infection, positive serology for hepatitis c. received oral, intramuscular or intravenous systemic immunosuppressants, or immune-modifying drugs for >14 days in total within 6 months prior to administration of study vaccine (for corticosteroids > / = 20 mg/day of prednisone equivalent). history of significant/severe wheeze, respiratory symptoms resulting in hospitalization, or known bronchial hyperreactivity to viruses. received immunoglobulin or blood-derived products, within 3 months prior to study vaccine dose. received chemotherapy, immunotherapy or radiation therapy within 6 months prior to study vaccine dose. study personnel or an immediate family member or household member of study personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing day (fever defined as > / = 38.0 degrees celsius /100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. receipt or anticipated receipt of, within 7 days prior to through 28 days after trial vaccination, any intranasal medication including fda-approved prescription or over-the-counter products or non-fda-approved alternative medicine products (e.g., ayurvedic oil or other naturopathic substances). currently smoking or vaping, or history of regular smoking or vaping in the past two years active alcohol use disorder or alcohol abuse or active illicit drug abuse anticipated use of nasal irrigation (e.g., neti pot™) after enrollment through 28 days after trial vaccination.

receipt of approved or authorized covid vaccine < 150 days prior to planned study vaccine administration or planned receipt of covid vaccine during 6 months following receipt of study vaccine. covid infection (positive covid-19 test) < 150 days prior to planned study vaccine administration pregnant or breastfeeding participants. history of severe covid-19 infection (e.g., need for oxygenation or ventilatory support) receipt of sars-cov-2 immunoglobulin, monoclonal antibody or plasma antibody therapy < 150 days prior to study vaccine administration any prior receipt of a piv5-based vaccine (e.g., cvxga1 or blb-201 [an rsv vaccine being developed by blue lake biotechnology]). chronic rhinitis, nasal septal defect causing significant breathing problems, cleft palate, nasal polyps, or other nasal abnormality that might affect vaccine administration. current or planned simultaneous participation in another interventional study or receipt of any investigational study product within 28 days prior to study vaccine administration a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine (licensed or unlicensed). a history of myocarditis or pericarditis at any time prior to enrollment, history of kawasaki disease, or history of multisystem inflammatory syndrome after covid infection. received or plans to receive a vaccine within 14 days prior to or after study vaccine. bleeding disorder diagnosed by a healthcare provider (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or bleeding difficulties with intramuscular injections or blood draws. current or previous diagnosis of a significant immunocompromising condition or other immunosuppressive condition. resides with someone who is severely immunocompromised. advanced liver or kidney diseases. advanced (cd4 count < 200) and/or untreated hiv, active hepatitis b virus infection, positive serology for hepatitis c. received oral, intramuscular or intravenous systemic immunosuppressants, or immune-modifying drugs for >14 days in total within 6 months prior to administration of study vaccine (for corticosteroids > / = 20 mg/day of prednisone equivalent). history of significant/severe wheeze, respiratory symptoms resulting in hospitalization, or known bronchial hyperreactivity to viruses. received immunoglobulin or blood-derived products, within 3 months prior to study vaccine dose. received chemotherapy, immunotherapy or radiation therapy within 6 months prior to study vaccine dose. study personnel or an immediate family member or household member of study personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing day (fever defined as > / = 38.0 degrees celsius /100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. receipt or anticipated receipt of, within 7 days prior to through 28 days after trial vaccination, any intranasal medication including fda-approved prescription or over-the-counter products or non-fda-approved alternative medicine products (e.g., ayurvedic oil or other naturopathic substances). currently smoking or vaping, or history of regular smoking or vaping in the past two years active alcohol use disorder or alcohol abuse or active illicit drug abuse anticipated use of nasal irrigation (e.g., neti pot™) after enrollment through 28 days after trial vaccination.