participants meeting any of the following criteria will be excluded from the study: known history of sars-cov-2 infection. (for cohort 1 and the primary series of cohort 2). prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. receipt of any investigational study product within 28 days prior to enrollment. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws, or previously experienced thrombosis with thrombocytopenia (tts) or heparin-induced thrombocytopenia. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. an immediate family member or household member of this study's personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: known history of sars-cov-2 infection. (for cohort 1 and the primary series of cohort 2). prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. receipt of any investigational study product within 28 days prior to enrollment. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws, or previously experienced thrombosis with thrombocytopenia (tts) or heparin-induced thrombocytopenia. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. an immediate family member or household member of this study's personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: known history of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection. prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. receipt of any investigational study product within 28 days prior to enrollment. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws, or previously experienced thrombosis with thrombocytopenia (tts) or heparin-induced thrombocytopenia. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. an immediate family member or household member of this study's personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: known history of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection. prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. receipt of any investigational study product within 28 days prior to enrollment. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws, or previously experienced thrombosis with thrombocytopenia (tts) or heparin-induced thrombocytopenia. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. an immediate family member or household member of this study's personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: 1. known history of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection. 2. prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. 3. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). 4. a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. 5. receipt of any investigational study product within 28 days prior to enrollment. 6. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). 7. bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws, or previously experienced thrombosis with thrombocytopenia (tts) or heparin-induced thrombocytopenia. 8. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. 9. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. 10. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. 11. an immediate family member or household member of this study's personnel. 12. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: 1. known history of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection. 2. prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. 3. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). 4. a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. 5. receipt of any investigational study product within 28 days prior to enrollment. 6. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). 7. bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws, or previously experienced thrombosis with thrombocytopenia (tts) or heparin-induced thrombocytopenia. 8. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. 9. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. 10. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. 11. an immediate family member or household member of this study's personnel. 12. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: known history of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection. prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. receipt of any investigational study product within 28 days prior to enrollment. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws, or previously experienced thrombosis with thrombocytopenia (tts) or heparin-induced thrombocytopenia. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. an immediate family member or household member of this study's personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: known history of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection. prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. receipt of any investigational study product within 28 days prior to enrollment. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws, or previously experienced thrombosis with thrombocytopenia (tts) or heparin-induced thrombocytopenia. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. an immediate family member or household member of this study's personnel. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: 1. known history of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection. 2. prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. 3. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). 4. a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. 5. receipt of any investigational study product within 28 days prior to enrollment. 6. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). 7. bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws. 8. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. 9. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. 10. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. 11. an immediate family member or household member of this study's personnel. 12. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.

participants meeting any of the following criteria will be excluded from the study: 1. known history of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection. 2. prior administration of an investigational coronavirus (sars coronavirus (sars-cov), middle east respiratory syndrome (mers-cov)) vaccine or sars coronavirus 2 (sars-cov-2) monoclonal antibody in the preceding 90 days or current/planned simultaneous participation in another interventional study. 3. receipt of sars coronavirus 2 (sars-cov-2) vaccine prior to study entry (cohort 2 only). 4. a history of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine or nanolipid particles. 5. receipt of any investigational study product within 28 days prior to enrollment. 6. received or plans to receive a vaccine within 28 days prior to the first dose (day 1) or plans to receive a non-study vaccine within 28 days prior to or after any dose of study vaccine (with exception for seasonal influenza vaccine within 14 days of study vaccine). 7. bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with intramuscular injections or blood draws. 8. current or previous diagnosis of immunocompromising condition, immune-mediated disease, or other immunosuppressive condition. 9. received systemic immunosuppressants or immune-modifying drugs for >14 days in total within 6 months prior to screening (for corticosteroids >/= 20 milligram per day of prednisone equivalent). topical tacrolimus is allowed if not used within 14 days prior to day 1. 10. received immunoglobulin, blood-derived products, within 90 days prior to first study vaccination. 11. an immediate family member or household member of this study's personnel. 12. is acutely ill or febrile 72 hours prior to or at vaccine dosing (fever defined as >/= 38.0 degrees celsius or 100.4 degrees fahrenheit). participants meeting this criterion may be rescheduled within the relevant window periods. afebrile participants with minor illnesses can be enrolled at the discretion of the investigator.