inclusion criteria: * healthy man and woman between 18-60 years old (inclusive) for the adult cohort and between 61-75 years old (inclusive) for the elderly cohort. * have a body-mass index of 18.0-30.0 kg/m² at screening * give informed consent prior to study enrollment and all study procedures * participants 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 * 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 clinicallysignificant" per investigator decision based on safety 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 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 * female participants of childbearing potential must not be pregnant or breastfeeding. * women of non-child-bearing potential must: 1. be classified as being postmenopausal (defined as having a history of amenorrhea for at least one year), or 2. where history of amenorrhea is less than one year, female participants must have a follicle stimulating hormone (fsh) level \> 40 milli-international units per millilitre (miu/ml), or 3. have a documented status 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 * 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 85 to 150 millimeters of mercury (mm hg), inclusive, at screening * participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: * healthy man and woman between 18-60 years old (inclusive) for the adult cohort and between 61-75 years old (inclusive) for the elderly cohort. * have a body-mass index of 18.0-30.0 kg/m² at screening * give informed consent prior to study enrollment and all study procedures * participants 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 * 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 clinicallysignificant" per investigator decision based on safety 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 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 * female participants of childbearing potential must not be pregnant or breastfeeding. * women of non-child-bearing potential must: 1. be classified as being postmenopausal (defined as having a history of amenorrhea for at least one year), or 2. where history of amenorrhea is less than one year, female participants must have a follicle stimulating hormone (fsh) level \> 40 milli-international units per millilitre (miu/ml), or 3. have a documented status 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 * 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 85 to 150 millimeters of mercury (mm hg), inclusive, at screening * participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: healthy man and woman between 18-60 years old (inclusive) for the adult cohort and between 61-75 years old (inclusive) for the elderly cohort. have a body-mass index of 18.0-30.0 kg/m² at screening give informed consent prior to study enrollment and all study procedures participants 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 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 clinicallysignificant" per investigator decision based on safety 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 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 female participants of childbearing potential must not be pregnant or breastfeeding. 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 follicle stimulating hormone (fsh) level > 40 milli-international units per millilitre (miu/ml), or have a documented status 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 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 85 to 150 millimeters of mercury (mm hg), inclusive, at screening participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: healthy man and woman between 18-60 years old (inclusive) for the adult cohort and between 61-75 years old (inclusive) for the elderly cohort. have a body-mass index of 18.0-30.0 kg/m² at screening give informed consent prior to study enrollment and all study procedures participants 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 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 clinicallysignificant" per investigator decision based on safety 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 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 female participants of childbearing potential must not be pregnant or breastfeeding. 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 follicle stimulating hormone (fsh) level > 40 milli-international units per millilitre (miu/ml), or have a documented status 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 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 85 to 150 millimeters of mercury (mm hg), inclusive, at screening participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: healthy man and woman between 18-ุ60 years old (inclusive) for the adult cohort and between 61-75 years old (inclusive) for the elderly cohort. have a body-mass index of 18.0-30.0 kg/m² at screening give informed consent prior to study enrollment and all study procedures participants 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 participants must have haematology, clinical chemistry, coagulation, and urinalysis test results that are not deviating from the normal reference range by age and gender to a clinically relevant extent 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 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 female participants of childbearing potential must not be pregnant or breastfeeding. 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 follicle stimulating hormone (fsh) level > 40 milli-international units per millilitre (miu/ml), or have a documented status 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 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 85 to 150 millimeters of mercury (mm hg), inclusive, at screening participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: healthy man and woman between 18-ุ60 years old (inclusive) for the adult cohort and between 61-75 years old (inclusive) for the elderly cohort. have a body-mass index of 18.0-30.0 kg/m² at screening give informed consent prior to study enrollment and all study procedures participants 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 participants must have haematology, clinical chemistry, coagulation, and urinalysis test results that are not deviating from the normal reference range by age and gender to a clinically relevant extent 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 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 female participants of childbearing potential must not be pregnant or breastfeeding. 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 follicle stimulating hormone (fsh) level > 40 milli-international units per millilitre (miu/ml), or have a documented status 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 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 85 to 150 millimeters of mercury (mm hg), inclusive, at screening participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: - healthy man and woman between 18-ุ60 years old (inclusive) for the adult cohort and between 61-75 years old (inclusive) for the elderly cohort. - have a body-mass index of 18.0-30.0 kg/m² at screening - give informed consent prior to study enrollment and all study procedures - participants 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 - participants must have haematology, clinical chemistry, coagulation, and urinalysis test results that are not deviating from the normal reference range by age and gender to a clinically relevant extent 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 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 - female participants of childbearing potential must not be pregnant or breastfeeding. - women of non-child-bearing potential must: 1. be classified as being postmenopausal (defined as having a history of amenorrhea for at least one year), or 2. where history of amenorrhea is less than one year, female participants must have a follicle stimulating hormone (fsh) level > 40 milli-international units per millilitre (miu/ml), or 3. have a documented status 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 - 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 85 to 150 millimeters of mercury (mm hg), inclusive, at screening - participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: - healthy man and woman between 18-ุ60 years old (inclusive) for the adult cohort and between 61-75 years old (inclusive) for the elderly cohort. - have a body-mass index of 18.0-30.0 kg/m² at screening - give informed consent prior to study enrollment and all study procedures - participants 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 - participants must have haematology, clinical chemistry, coagulation, and urinalysis test results that are not deviating from the normal reference range by age and gender to a clinically relevant extent 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 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 - female participants of childbearing potential must not be pregnant or breastfeeding. - women of non-child-bearing potential must: 1. be classified as being postmenopausal (defined as having a history of amenorrhea for at least one year), or 2. where history of amenorrhea is less than one year, female participants must have a follicle stimulating hormone (fsh) level > 40 milli-international units per millilitre (miu/ml), or 3. have a documented status 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 - 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 85 to 150 millimeters of mercury (mm hg), inclusive, at screening - participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: - healthy man and woman between 18-ุ60 years old (inclusive) for the adult cohort and between >60-75 years old (inclusive) for the elderly cohort. - have a body-mass index of 18.0-30.0 kg/m² at screening - give informed consent prior to study enrollment and all study procedures - participants 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 - participants must have haematology, clinical chemistry, coagulation, and urinalysis test results that are not deviating from the normal reference range by age and gender to a clinically relevant extent 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 must have negative-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: 1. be classified as being postmenopausal (defined as having a history of amenorrhea for at least one year), or 2. where history of amenorrhea is less than one year, female participants must have a follicle stimulating hormone (fsh) level > 40 milli-international units per millilitre (miu/ml), or 3. have a documented status 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 and for acute exposure using rt-pcr and must have a negative result - body temperature measured orally must be less than 37.8ºc at screening. - pulse must be no greater than 100 beats per minute, at screening - systolic blood pressure (sbp) must be between 85 to 150 millimeters of mercury (mm hg), inclusive, at screening - participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study

inclusion criteria: - healthy man and woman between 18-ุ60 years old (inclusive) for the adult cohort and between >60-75 years old (inclusive) for the elderly cohort. - have a body-mass index of 18.0-30.0 kg/m² at screening - give informed consent prior to study enrollment and all study procedures - participants 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 - participants must have haematology, clinical chemistry, coagulation, and urinalysis test results that are not deviating from the normal reference range by age and gender to a clinically relevant extent 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 must have negative-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: 1. be classified as being postmenopausal (defined as having a history of amenorrhea for at least one year), or 2. where history of amenorrhea is less than one year, female participants must have a follicle stimulating hormone (fsh) level > 40 milli-international units per millilitre (miu/ml), or 3. have a documented status 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 and for acute exposure using rt-pcr and must have a negative result - body temperature measured orally must be less than 37.8ºc at screening. - pulse must be no greater than 100 beats per minute, at screening - systolic blood pressure (sbp) must be between 85 to 150 millimeters of mercury (mm hg), inclusive, at screening - participants must agree to refrain from donating blood, plasma, ovules, sperm, or organs during the whole study