1) Subjects who previously received a vaccine against SARS-CoV-2 2) Subjects with close contact with a COVID-19 patient within 30 days prior to immunization of the investigational product (according to the definition of close contacts by the National Institute of Infectious Diseases3) Subjects with a personal or family history of seizures, epilepsy, encephalopathy, or psychiatric disease4) Subjects allergic to any of the ingredients of the test product or placebo5) Subjects with a history of serious allergic reactions to vaccines6) Subjects with any acute febrile disease or infectious disease7) Subjects with a history of severe acute respiratory syndrome (SARS), middle east respiratory syndrome (MERS) or COVID-198) Subjects with a history of serious cardiovascular, respiratory, hematological, digestive, endocrine, neuropsychiatric, hepatic, or renal disease9) Subjects with hereditary or acquired vascular/neurogenic edema10) Subjects who had urticaria within 1 year prior to immunization of the investigational product11) Subjects with asplenism, post-splenectomy or functional asplenism12) Subjects with thrombocytopenia or any other coagulation disorder (possible contraindication to intramuscular injection)13) Subjects with vasovagal reactions to needle insertion14) Subjects who received immunosuppressive therapy, antiallergic therapy, cytotoxic therapy, or oral or inhaled corticosteroids (but not nasal corticosteroid sprays or topical corticosteroids) within 6 months prior to immunization of the investigational product15) Subjects who received any blood product within 4 months prior to immunization of the investigational product16) Subjects who participated in any other clinical trial or received any other study drug within 1 month prior to immunization of the investigational product in this study17) Subjects who received an attenuated vaccine within 1 month prior to immunization of the investigational product18) Subjects who received a subunit vaccine or inactivated vaccine within 14 days prior to immunization of the investigational product19) Subjects receiving anti-tuberculosis therapy20) Females with a positive pregnancy test. Females who are pregnant or breastfeeding or who plan to become pregnant within 6 months after immunization of the investigational product21) Subjects judged by the investigator or sub-investigator to be inappropriate for participation in this study

1) Subjects who previously received a vaccine against SARS-CoV-2 2) Subjects with close contact with a COVID-19 patient within 30 days prior to immunization of the investigational product (according to the definition of close contacts by the National Institute of Infectious Diseases3) Subjects with a personal or family history of seizures, epilepsy, encephalopathy, or psychiatric disease4) Subjects allergic to any of the ingredients of the test product or placebo5) Subjects with a history of serious allergic reactions to vaccines6) Subjects with any acute febrile disease or infectious disease7) Subjects with a history of severe acute respiratory syndrome (SARS), middle east respiratory syndrome (MERS) or COVID-198) Subjects with a history of serious cardiovascular, respiratory, hematological, digestive, endocrine, neuropsychiatric, hepatic, or renal disease9) Subjects with hereditary or acquired vascular/neurogenic edema10) Subjects who had urticaria within 1 year prior to immunization of the investigational product11) Subjects with asplenism, post-splenectomy or functional asplenism12) Subjects with thrombocytopenia or any other coagulation disorder (possible contraindication to intramuscular injection)13) Subjects with vasovagal reactions to needle insertion14) Subjects who received immunosuppressive therapy, antiallergic therapy, cytotoxic therapy, or oral or inhaled corticosteroids (but not nasal corticosteroid sprays or topical corticosteroids) within 6 months prior to immunization of the investigational product15) Subjects who received any blood product within 4 months prior to immunization of the investigational product16) Subjects who participated in any other clinical trial or received any other study drug within 1 month prior to immunization of the investigational product in this study17) Subjects who received an attenuated vaccine within 1 month prior to immunization of the investigational product18) Subjects who received a subunit vaccine or inactivated vaccine within 14 days prior to immunization of the investigational product19) Subjects receiving anti-tuberculosis therapy20) Females with a positive pregnancy test. Females who are pregnant or breastfeeding or who plan to become pregnant within 6 months after immunization of the investigational product21) Subjects judged by the investigator or sub-investigator to be inappropriate for participation in this study