Medical Conditions: 1. Phase 1 only: Past clinical (based on COVID-19 symptoms/signs alone, if a SARS CoV 2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID 19. 2. Phase 1 only: Known infection with HIV, HCV, or HBV. 3. Receipt of medications intended to prevent COVID-19. 4. Previous or current diagnosis of MIS-C. 5. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator’s judgment, make the participant inappropriate for the study. 6. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s). 7. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 8. Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic lupus erythematosus. 9. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 10. Female who is pregnant or breastfeeding. Prior/Concomitant Therapy: 11. Previous vaccination with any coronavirus vaccine. 12. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. 13. Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 60 days before study intervention administration, or receipt of any passive antibody therapy specific to COVID-19 from 90 days before study intervention administration, or planned receipt throughout the study. Prior/Concurrent Clinical Study Experience: 14. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation. 15. Previous participation in other studies involving study intervention containing LNPs. Diagnostic Assessments: Not applicable. Other Exclusions: 16. Participants who are direct descendants (child or grandchild) of investigational site staff members or Pfizer/BioNTech employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.

Medical Conditions: 1. Phase 1 only: Past clinical (based on COVID-19 symptoms/signs alone, if a SARS CoV 2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID 19. 2. Phase 1 only: Known infection with HIV, HCV, or HBV. 3. Receipt of medications intended to prevent COVID-19. 4. Previous or current diagnosis of MIS-C. 5. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator’s judgment, make the participant inappropriate for the study. 6. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s). 7. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 8. Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic lupus erythematosus. 9. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 10. Female who is pregnant or breastfeeding. Prior/Concomitant Therapy: 11. Previous vaccination with any coronavirus vaccine. 12. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. 13. Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 60 days before study intervention administration, or receipt of any passive antibody therapy specific to COVID-19 from 90 days before study intervention administration, or planned receipt throughout the study. Prior/Concurrent Clinical Study Experience: 14. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation. 15. Previous participation in other studies involving study intervention containing LNPs. Diagnostic Assessments: Not applicable. Other Exclusions: 16. Participants who are direct descendants (child or grandchild) of investigational site staff members or Pfizer/BioNTech employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.

Medical Conditions: 1. Phase 1 only: Past clinical (based on COVID-19 symptoms/signs alone, if a SARS CoV 2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID 19. 2. Phase 1 only: Known infection with HIV, HCV, or HBV. 3. Receipt of medications intended to prevent COVID-19. 4. Previous or current diagnosis of MIS-C. 5. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. Note: This includes both conditions that may increase the risk associated with study intervention administration or a condition that may interfere with the interpretation of study results 6. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s). 7. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 8. Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic lupus erythematosus. Note: Stable type 1 diabetes and hypothyroidism are permitted. 9. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 10. Female who is pregnant or breastfeeding. Prior/Concomitant Therapy: 11. Previous vaccination with any coronavirus vaccine. 12. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. 13. Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 60 days before study intervention administration, or receipt of any passive antibody therapy specific to COVID-19 from 90 days before study intervention administration, or planned receipt throughout the study. Prior/Concurrent Clinical Study Experience: 14. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation. 15. Previous participation in other studies involving study intervention containing LNPs. Diagnostic Assessments: Not applicable. Other Exclusions: 16. Participants who are direct descendants (child or grandchild) of investigational site staff members or Pfizer/BioNTech employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.

Medical Conditions: 1. Phase 1 only: Past clinical (based on COVID-19 symptoms/signs alone, if a SARS CoV 2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID 19. 2. Phase 1 only: Known infection with HIV, HCV, or HBV. 3. Receipt of medications intended to prevent COVID-19. 4. Previous or current diagnosis of MIS-C. 5. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. Note: This includes both conditions that may increase the risk associated with study intervention administration or a condition that may interfere with the interpretation of study results 6. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s). 7. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 8. Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic lupus erythematosus. Note: Stable type 1 diabetes and hypothyroidism are permitted. 9. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 10. Female who is pregnant or breastfeeding. Prior/Concomitant Therapy: 11. Previous vaccination with any coronavirus vaccine. 12. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. 13. Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 60 days before study intervention administration, or receipt of any passive antibody therapy specific to COVID-19 from 90 days before study intervention administration, or planned receipt throughout the study. Prior/Concurrent Clinical Study Experience: 14. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation. 15. Previous participation in other studies involving study intervention containing LNPs. Diagnostic Assessments: Not applicable. Other Exclusions: 16. Participants who are direct descendants (child or grandchild) of investigational site staff members or Pfizer/BioNTech employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.

Medical Conditions: 1. Phase 1 only: Past clinical (based on COVID-19 symptoms/signs alone, if a SARS CoV 2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID 19. 2. Phase 1 only: Known infection with HIV, HCV, or HBV. 3. Receipt of medications intended to prevent COVID-19. 4. Previous or current diagnosis of MIS-C. 5. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator’s judgment, make the participant inappropriate for the study. 6. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s). 7. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 8. Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic lupus erythematosus. 9. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 10. Female who is pregnant or breastfeeding. Prior/Concomitant Therapy: 11. Previous vaccination with any coronavirus vaccine. 12. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. 13. Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 60 days before study intervention administration, or receipt of any passive antibody therapy specific to COVID-19 from 90 days before study intervention administration, or planned receipt throughout the study. Prior/Concurrent Clinical Study Experience: 14. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation. 15. Previous participation in other studies involving study intervention containing LNPs. Diagnostic Assessments: Not applicable. Other Exclusions: 16. Participants who are direct descendants (child or grandchild) of investigational site staff members or Pfizer/BioNTech employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.

Medical Conditions: 1. Phase 1 only: Past clinical (based on COVID-19 symptoms/signs alone, if a SARS CoV 2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID 19. 2. Phase 1 only: Known infection with HIV, HCV, or HBV. 3. Receipt of medications intended to prevent COVID-19. 4. Previous or current diagnosis of MIS-C. 5. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator’s judgment, make the participant inappropriate for the study. 6. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s). 7. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 8. Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic lupus erythematosus. 9. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 10. Female who is pregnant or breastfeeding. Prior/Concomitant Therapy: 11. Previous vaccination with any coronavirus vaccine. 12. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. 13. Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 60 days before study intervention administration, or receipt of any passive antibody therapy specific to COVID-19 from 90 days before study intervention administration, or planned receipt throughout the study. Prior/Concurrent Clinical Study Experience: 14. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation. 15. Previous participation in other studies involving study intervention containing LNPs. Diagnostic Assessments: Not applicable. Other Exclusions: 16. Participants who are direct descendants (child or grandchild) of investigational site staff members or Pfizer/BioNTech employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.