1. individuals with fever \>37.3°c (axillary), or any acute illness at baseline (day 1) or within 3 days prior to randomization. participants meeting this criterion may be rescheduled within the relevant window. febrile participants with minor illnesses can be enrolled at the discretion of the investigator. 2. individuals with laboratory-confirmed sars-cov-2 infection \[as defined by reverse transcriptase polymerase chain reaction (rt-pcr) assay or rapid covid-19 antigen test or an equivalent at visit 1\] or with history of covid-19, or individual with covid-19 pandemic area contaction confirmed with inspection or health code on cellphone. 3. individuals who have received an investigational or authorized covid-19 vaccine prior to day 1, or plan to receive covid-19 vaccine during the study period. 4. any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease \[e.g., malignancy, human immunodeficiency virus (hiv) infection\] or immunosuppressive/cytotoxic therapy (e.g., systemic corticosteroids, medications used for cancer chemotherapy, organ transplantation or to treat autoimmune disorders) within 3 months prior to day 1. 5. individuals with any progressive unstable or uncontrolled clinical conditions. 6. individuals who are pregnant, or breastfeeding, or planning to become pregnant while enrolled in this study or during the study period. 7. individuals who have a history of severe adverse reaction associated with a vaccine or severe allergic reaction \[e.g., anaphylaxis to any component of the study vaccines (cpg 1018, aluminum), or scb-2019 components as outlined in the latest ib\]. 8. individuals who have a history of malignancy within 1 year before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix which have been cured, or other malignancies with minimal risk of recurrence). 9. individuals who have received any other investigational product within 30 days prior to day 1 or intend to participate in another clinical study at any time during the conduct of this study. 10. individuals who have received any other licensed vaccines within 14 days prior to enrollment in this study or who are planning to receive any vaccine up to day 53. 11. individuals with known bleeding disorder that would, in the opinion of the investigator, contraindicate intramuscular injection. 12. individuals who have received treatment with rituximab or any other anti-cd20 monoclonal antibodies within 9 months prior to day 1 or planned during the study period. 13. administration of intravenous immunoglobulins and/or any blood products within 3 months prior to enrollment or planned administration during the study period. 14. individuals with any condition that, in the opinion of the investigator, would interfere with the primary study objectives or pose additional risk to the participant.

1. individuals with fever \>37.3°c (axillary), or any acute illness at baseline (day 1) or within 3 days prior to randomization. participants meeting this criterion may be rescheduled within the relevant window. febrile participants with minor illnesses can be enrolled at the discretion of the investigator. 2. individuals with laboratory-confirmed sars-cov-2 infection \[as defined by reverse transcriptase polymerase chain reaction (rt-pcr) assay or rapid covid-19 antigen test or an equivalent at visit 1\] or with history of covid-19, or individual with covid-19 pandemic area contaction confirmed with inspection or health code on cellphone. 3. individuals who have received an investigational or authorized covid-19 vaccine prior to day 1, or plan to receive covid-19 vaccine during the study period. 4. any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease \[e.g., malignancy, human immunodeficiency virus (hiv) infection\] or immunosuppressive/cytotoxic therapy (e.g., systemic corticosteroids, medications used for cancer chemotherapy, organ transplantation or to treat autoimmune disorders) within 3 months prior to day 1. 5. individuals with any progressive unstable or uncontrolled clinical conditions. 6. individuals who are pregnant, or breastfeeding, or planning to become pregnant while enrolled in this study or during the study period. 7. individuals who have a history of severe adverse reaction associated with a vaccine or severe allergic reaction \[e.g., anaphylaxis to any component of the study vaccines (cpg 1018, aluminum), or scb-2019 components as outlined in the latest ib\]. 8. individuals who have a history of malignancy within 1 year before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix which have been cured, or other malignancies with minimal risk of recurrence). 9. individuals who have received any other investigational product within 30 days prior to day 1 or intend to participate in another clinical study at any time during the conduct of this study. 10. individuals who have received any other licensed vaccines within 14 days prior to enrollment in this study or who are planning to receive any vaccine up to day 53. 11. individuals with known bleeding disorder that would, in the opinion of the investigator, contraindicate intramuscular injection. 12. individuals who have received treatment with rituximab or any other anti-cd20 monoclonal antibodies within 9 months prior to day 1 or planned during the study period. 13. administration of intravenous immunoglobulins and/or any blood products within 3 months prior to enrollment or planned administration during the study period. 14. individuals with any condition that, in the opinion of the investigator, would interfere with the primary study objectives or pose additional risk to the participant.

individuals with fever >37.3°c (axillary), or any acute illness at baseline (day 1) or within 3 days prior to randomization. participants meeting this criterion may be rescheduled within the relevant window. febrile participants with minor illnesses can be enrolled at the discretion of the investigator. individuals with laboratory-confirmed sars-cov-2 infection [as defined by reverse transcriptase polymerase chain reaction (rt-pcr) assay or rapid covid-19 antigen test or an equivalent at visit 1] or with history of covid-19, or individual with covid-19 pandemic area contaction confirmed with inspection or health code on cellphone. individuals who have received an investigational or authorized covid-19 vaccine prior to day 1, or plan to receive covid-19 vaccine during the study period. any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease [e.g., malignancy, human immunodeficiency virus (hiv) infection] or immunosuppressive/cytotoxic therapy (e.g., systemic corticosteroids, medications used for cancer chemotherapy, organ transplantation or to treat autoimmune disorders) within 3 months prior to day 1. individuals with any progressive unstable or uncontrolled clinical conditions. individuals who are pregnant, or breastfeeding, or planning to become pregnant while enrolled in this study or during the study period. individuals who have a history of severe adverse reaction associated with a vaccine or severe allergic reaction [e.g., anaphylaxis to any component of the study vaccines (cpg 1018, aluminum), or scb-2019 components as outlined in the latest ib]. individuals who have a history of malignancy within 1 year before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix which have been cured, or other malignancies with minimal risk of recurrence). individuals who have received any other investigational product within 30 days prior to day 1 or intend to participate in another clinical study at any time during the conduct of this study. individuals who have received any other licensed vaccines within 14 days prior to enrollment in this study or who are planning to receive any vaccine up to day 53. individuals with known bleeding disorder that would, in the opinion of the investigator, contraindicate intramuscular injection. individuals who have received treatment with rituximab or any other anti-cd20 monoclonal antibodies within 9 months prior to day 1 or planned during the study period. administration of intravenous immunoglobulins and/or any blood products within 3 months prior to enrollment or planned administration during the study period. individuals with any condition that, in the opinion of the investigator, would interfere with the primary study objectives or pose additional risk to the participant.

individuals with fever >37.3°c (axillary), or any acute illness at baseline (day 1) or within 3 days prior to randomization. participants meeting this criterion may be rescheduled within the relevant window. febrile participants with minor illnesses can be enrolled at the discretion of the investigator. individuals with laboratory-confirmed sars-cov-2 infection [as defined by reverse transcriptase polymerase chain reaction (rt-pcr) assay or rapid covid-19 antigen test or an equivalent at visit 1] or with history of covid-19, or individual with covid-19 pandemic area contaction confirmed with inspection or health code on cellphone. individuals who have received an investigational or authorized covid-19 vaccine prior to day 1, or plan to receive covid-19 vaccine during the study period. any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease [e.g., malignancy, human immunodeficiency virus (hiv) infection] or immunosuppressive/cytotoxic therapy (e.g., systemic corticosteroids, medications used for cancer chemotherapy, organ transplantation or to treat autoimmune disorders) within 3 months prior to day 1. individuals with any progressive unstable or uncontrolled clinical conditions. individuals who are pregnant, or breastfeeding, or planning to become pregnant while enrolled in this study or during the study period. individuals who have a history of severe adverse reaction associated with a vaccine or severe allergic reaction [e.g., anaphylaxis to any component of the study vaccines (cpg 1018, aluminum), or scb-2019 components as outlined in the latest ib]. individuals who have a history of malignancy within 1 year before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix which have been cured, or other malignancies with minimal risk of recurrence). individuals who have received any other investigational product within 30 days prior to day 1 or intend to participate in another clinical study at any time during the conduct of this study. individuals who have received any other licensed vaccines within 14 days prior to enrollment in this study or who are planning to receive any vaccine up to day 53. individuals with known bleeding disorder that would, in the opinion of the investigator, contraindicate intramuscular injection. individuals who have received treatment with rituximab or any other anti-cd20 monoclonal antibodies within 9 months prior to day 1 or planned during the study period. administration of intravenous immunoglobulins and/or any blood products within 3 months prior to enrollment or planned administration during the study period. individuals with any condition that, in the opinion of the investigator, would interfere with the primary study objectives or pose additional risk to the participant.

1. individuals with fever >37.3°c (axillary), or any acute illness at baseline (day 1) or within 3 days prior to randomization. participants meeting this criterion may be rescheduled within the relevant window. febrile participants with minor illnesses can be enrolled at the discretion of the investigator. 2. individuals with laboratory-confirmed sars-cov-2 infection [as defined by reverse transcriptase polymerase chain reaction (rt-pcr) assay or rapid covid-19 antigen test or an equivalent at visit 1] or with history of covid-19, or individual with covid-19 pandemic area contaction confirmed with inspection or health code on cellphone. 3. individuals who have received an investigational or authorized covid-19 vaccine prior to day 1, or plan to receive covid-19 vaccine during the study period. 4. any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease [e.g., malignancy, human immunodeficiency virus (hiv) infection] or immunosuppressive/cytotoxic therapy (e.g., systemic corticosteroids, medications used for cancer chemotherapy, organ transplantation or to treat autoimmune disorders) within 3 months prior to day 1. 5. individuals with any progressive unstable or uncontrolled clinical conditions. 6. individuals who are pregnant, or breastfeeding, or planning to become pregnant while enrolled in this study or during the study period. 7. individuals who have a history of severe adverse reaction associated with a vaccine or severe allergic reaction [e.g., anaphylaxis to any component of the study vaccines (cpg 1018, aluminum), or scb-2019 components as outlined in the latest ib]. 8. individuals who have a history of malignancy within 1 year before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix which have been cured, or other malignancies with minimal risk of recurrence). 9. individuals who have received any other investigational product within 30 days prior to day 1 or intend to participate in another clinical study at any time during the conduct of this study. 10. individuals who have received any other licensed vaccines within 14 days prior to enrollment in this study or who are planning to receive any vaccine up to day 53. 11. individuals with known bleeding disorder that would, in the opinion of the investigator, contraindicate intramuscular injection. 12. individuals who have received treatment with rituximab or any other anti-cd20 monoclonal antibodies within 9 months prior to day 1 or planned during the study period. 13. administration of intravenous immunoglobulins and/or any blood products within 3 months prior to enrollment or planned administration during the study period. 14. individuals with any condition that, in the opinion of the investigator, would interfere with the primary study objectives or pose additional risk to the participant.

1. individuals with fever >37.3°c (axillary), or any acute illness at baseline (day 1) or within 3 days prior to randomization. participants meeting this criterion may be rescheduled within the relevant window. febrile participants with minor illnesses can be enrolled at the discretion of the investigator. 2. individuals with laboratory-confirmed sars-cov-2 infection [as defined by reverse transcriptase polymerase chain reaction (rt-pcr) assay or rapid covid-19 antigen test or an equivalent at visit 1] or with history of covid-19, or individual with covid-19 pandemic area contaction confirmed with inspection or health code on cellphone. 3. individuals who have received an investigational or authorized covid-19 vaccine prior to day 1, or plan to receive covid-19 vaccine during the study period. 4. any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease [e.g., malignancy, human immunodeficiency virus (hiv) infection] or immunosuppressive/cytotoxic therapy (e.g., systemic corticosteroids, medications used for cancer chemotherapy, organ transplantation or to treat autoimmune disorders) within 3 months prior to day 1. 5. individuals with any progressive unstable or uncontrolled clinical conditions. 6. individuals who are pregnant, or breastfeeding, or planning to become pregnant while enrolled in this study or during the study period. 7. individuals who have a history of severe adverse reaction associated with a vaccine or severe allergic reaction [e.g., anaphylaxis to any component of the study vaccines (cpg 1018, aluminum), or scb-2019 components as outlined in the latest ib]. 8. individuals who have a history of malignancy within 1 year before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix which have been cured, or other malignancies with minimal risk of recurrence). 9. individuals who have received any other investigational product within 30 days prior to day 1 or intend to participate in another clinical study at any time during the conduct of this study. 10. individuals who have received any other licensed vaccines within 14 days prior to enrollment in this study or who are planning to receive any vaccine up to day 53. 11. individuals with known bleeding disorder that would, in the opinion of the investigator, contraindicate intramuscular injection. 12. individuals who have received treatment with rituximab or any other anti-cd20 monoclonal antibodies within 9 months prior to day 1 or planned during the study period. 13. administration of intravenous immunoglobulins and/or any blood products within 3 months prior to enrollment or planned administration during the study period. 14. individuals with any condition that, in the opinion of the investigator, would interfere with the primary study objectives or pose additional risk to the participant.