- history of any other covid-19 investigational or licensed vaccination. - known history of sars-cov-2 infection, as declared by the subject. - for women, positive urine pregnancy test before the first dose of vaccination, or any time during the study period. - temperature >38.0°c (100.4°f) or symptoms of an acute self-limited illness such as an upper respiratory infection or gastroenteritis within three days prior to each dose of vaccine. - resident of covid-19 infection in the same household. - known case of hiv, hepatitis b, or hepatitis c infection. - receipt of any licensed/experimental vaccine within four weeks before enrolment in this study. - receipt of immunoglobulin or other blood products within the three months before vaccination in this study. - immunosuppression as a result of an underlying illness or treatment with immunosuppressive or cytotoxic drugs, or use of anticancer chemotherapy or radiation therapy within the preceding 36 months. - immunoglobulins, anti-cytokine antibodies, and blood products within 6 months prior to study vaccination, during, and 21 days following the last dose of vaccination. - pregnancy, lactation, or willingness/intention to become pregnant during the first 6 months after enrolment. - severe and/or uncontrolled cardiovascular disease, respiratory disease, gastrointestinal disease, liver disease, renal disease, an endocrine disorder, and neurological illness (mild/moderate well-controlled comorbidities are allowed) re-vaccination exclusion criteria - pregnancy. - history of virologically (rt-pcr) confirmed sars-cov-2 infection - anaphylactic reaction following administration of the investigational vaccine.

- history of any other covid-19 investigational or licensed vaccination. - known history of sars-cov-2 infection, as declared by the subject. - for women, positive urine pregnancy test before the first dose of vaccination, or any time during the study period. - temperature >38.0°c (100.4°f) or symptoms of an acute self-limited illness such as an upper respiratory infection or gastroenteritis within three days prior to each dose of vaccine. - resident of covid-19 infection in the same household. - known case of hiv, hepatitis b, or hepatitis c infection. - receipt of any licensed/experimental vaccine within four weeks before enrolment in this study. - receipt of immunoglobulin or other blood products within the three months before vaccination in this study. - immunosuppression as a result of an underlying illness or treatment with immunosuppressive or cytotoxic drugs, or use of anticancer chemotherapy or radiation therapy within the preceding 36 months. - immunoglobulins, anti-cytokine antibodies, and blood products within 6 months prior to study vaccination, during, and 21 days following the last dose of vaccination. - pregnancy, lactation, or willingness/intention to become pregnant during the first 6 months after enrolment. - severe and/or uncontrolled cardiovascular disease, respiratory disease, gastrointestinal disease, liver disease, renal disease, an endocrine disorder, and neurological illness (mild/moderate well-controlled comorbidities are allowed) re-vaccination exclusion criteria - pregnancy. - history of virologically (rt-pcr) confirmed sars-cov-2 infection - anaphylactic reaction following administration of the investigational vaccine.