inclusion criteria: healthy man or woman between 18 to 64 years old (inclusive). give informed consent prior to study enrolment and all study procedures. participant must be able to comply with study procedures and be available for all study visits. participants must be in general good health based on medical history and physical examination as determined by the investigator(s) at screening. males must be surgically sterile (>30 days since vasectomy with no viable sperm), practice true abstinence, or, if engaged in sexual activities with a female with childbearing potential, use condoms from first vaccination until 60 days after the last vaccination. females of child-bearing potential must practice true abstinence, or, if engaged in sexual activities with a male, agree to use highly effective (failure rate of <1% per year when used consistently and correctly), double-barrier contraceptive measures throughout the study and intend to continue use of contraception methods for at least 60 days following the last vaccination. female participants of childbearing potential must not be pregnant or breastfeeding. body temperature measured at forehead using validated device must be less than 37.5ºc at screening. pulse must be no greater than 100 beats per minute at screening. systolic blood pressure (sbp) must be between 90 to 160 millimetres of mercury (mmhg), inclusive, at screening. participants must agree to refrain from donating blood, plasma, ovules, or sperm during the whole study. participants must have haematology, clinical chemistry, coagulation, and urinalysis test results that are not deviating from the normal reference range by age and gender or considered "not clinically significant" per investigator decision based on safety at screening. female participants of child-bearing potential must have negative serum pregnancy test by beta human chorionic gonadotropin [β-hcg] at screening and a negative urine-based pregnancy test within 24 hours prior to each investigational vaccine administration. women of non-child-bearing potential must: be classified as being postmenopausal (defined as having a history of amenorrhea for at least one year), or where history of amenorrhea is less than one-year, female participants must have a fsh level > 40 milli-international units per millilitre (miu/ml), or have a physical examination for evidence of being surgically sterile (hysterectomy, bilateral oophorectomy, or salpingectomy). all volunteers will be screened for serum antibodies against sars-cov-2 as evidence of previous infection using enzyme-linked immunosorbent assay (elisa) and must have a negative result.

inclusion criteria: healthy man or woman between 18 to 64 years old (inclusive). give informed consent prior to study enrolment and all study procedures. participant must be able to comply with study procedures and be available for all study visits. participants must be in general good health based on medical history and physical examination as determined by the investigator(s) at screening. males must be surgically sterile (>30 days since vasectomy with no viable sperm), practice true abstinence, or, if engaged in sexual activities with a female with childbearing potential, use condoms from first vaccination until 60 days after the last vaccination. females of child-bearing potential must practice true abstinence, or, if engaged in sexual activities with a male, agree to use highly effective (failure rate of <1% per year when used consistently and correctly), double-barrier contraceptive measures throughout the study and intend to continue use of contraception methods for at least 60 days following the last vaccination. female participants of childbearing potential must not be pregnant or breastfeeding. body temperature measured at forehead using validated device must be less than 37.5ºc at screening. pulse must be no greater than 100 beats per minute at screening. systolic blood pressure (sbp) must be between 90 to 160 millimetres of mercury (mmhg), inclusive, at screening. participants must agree to refrain from donating blood, plasma, ovules, or sperm during the whole study. participants must have haematology, clinical chemistry, coagulation, and urinalysis test results that are not deviating from the normal reference range by age and gender or considered "not clinically significant" per investigator decision based on safety at screening. female participants of child-bearing potential must have negative serum pregnancy test by beta human chorionic gonadotropin [β-hcg] at screening and a negative urine-based pregnancy test within 24 hours prior to each investigational vaccine administration. women of non-child-bearing potential must: be classified as being postmenopausal (defined as having a history of amenorrhea for at least one year), or where history of amenorrhea is less than one-year, female participants must have a fsh level > 40 milli-international units per millilitre (miu/ml), or have a physical examination for evidence of being surgically sterile (hysterectomy, bilateral oophorectomy, or salpingectomy). all volunteers will be screened for serum antibodies against sars-cov-2 as evidence of previous infection using enzyme-linked immunosorbent assay (elisa) and must have a negative result.