inclusion criteria: for adult group (age ≥18 and ≤55) * male or female subjects of ≥18 years old and ≤55 years old with body mass index (bmi) ≥18 and ≤30 at the screening visit. * individuals who are in good health condition at the time of entry into the trial as determined by medical history, physical examination (including vital signs, electrocardiogram \[ecg\]) and eligibility screening test (hematology, blood chemistry and urine analysis) and clinical judgment of the investigator at screening visit. * the subject can provide with informed consent and signs and dates a written informed consent form (icf) prior to the initiation of any trial procedures. * they must be able to understand and follow trial-related instructions. * they must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial. * negative in antibodies screening of sars-cov-2 (fingerstick). * normal in chest computed tomography (ct) scans (no imaging features of covid-19). * axillary temperature ≤ 37.0ºc. * negative sars-cov-2 test in throat swabs by reverse transcription-polymerase chain reaction (rt-pcr). * women of childbearing potential (wocbp) must have a negative beta-human chorionic gonadotropin (β-hcg) in serum sample at screening visit. women that are postmenopausal (menopause≥12 consecutive months) or permanently sterilized will be considered as not having reproductive potential. * wocbp must have used effective contraception 14 days prior to screening and agree to use effective contraception continuously during the trial period, from 14 days prior to screening visit to 60 days after the last immunization. * wocbp must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during trial, starting from screening visit and continuously until 60 days after being given the last immunization. * men who are sexually active with a wocbp and have not had a vasectomy must agree to practice an effective form of contraception with their female partner of childbearing potential during the trial, starting from screening visit and continuously until 60 days after being given the last immunization. * men must be willing to refrain from sperm donation, starting from screening visit and continuously until 60 days after receiving the last immunization. for the elderly group (age ≥65 and ≤85) * male or female subjects ≥65 years old and ≤85 years old at screening visit * individuals who are in a health condition that can receive the investigational vaccine, at the time of entry into the trial as determined by medical history, physical examination (including vital signs, ecg) and eligibility screening tests (hematology, biochemistry and urinalysis) and clinical judgment of the investigator at screening visit. * the subject can provide with informed consent and signs and dates a written icf prior to the initiation of any trial procedures. * they must be able to understand and follow trial-related instructions. * they must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial. * negative in antibodies screening of sars-cov-2 (blood sample from fingertip). * no imaging features of covid-19 in chest ct. * axillary temperature ≤ 37.0ºc. * negative sars-cov-2 test in throat swabs by rt-pcr. * wocbp must have a negative serum β-hcg at screening visit. women that are postmenopausal (menopause ≥12 consecutive months) or permanently sterilized will be considered as not having reproductive potential. * wocbp must have used effective contraception 14 days prior to screening and agree to use effective contraception continuously during the trial period, from 14 days prior to screening visit to 60 days after the last immunization. * wocbp must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during trial, starting from screening visit and continuously until 60 days after being given the last immunization. * men who are sexually active with a wocbp and have not had a vasectomy must agree to practice an effective form of contraception with their female partner of childbearing potential during the trial, starting from screening visit and continuously until 60 days after being given the last immunization. * men must be willing to refrain from sperm donation, starting from screening visit and continuously until 60 days after receiving the last immunization.

inclusion criteria: for adult group (age ≥18 and ≤55) * male or female subjects of ≥18 years old and ≤55 years old with body mass index (bmi) ≥18 and ≤30 at the screening visit. * individuals who are in good health condition at the time of entry into the trial as determined by medical history, physical examination (including vital signs, electrocardiogram \[ecg\]) and eligibility screening test (hematology, blood chemistry and urine analysis) and clinical judgment of the investigator at screening visit. * the subject can provide with informed consent and signs and dates a written informed consent form (icf) prior to the initiation of any trial procedures. * they must be able to understand and follow trial-related instructions. * they must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial. * negative in antibodies screening of sars-cov-2 (fingerstick). * normal in chest computed tomography (ct) scans (no imaging features of covid-19). * axillary temperature ≤ 37.0ºc. * negative sars-cov-2 test in throat swabs by reverse transcription-polymerase chain reaction (rt-pcr). * women of childbearing potential (wocbp) must have a negative beta-human chorionic gonadotropin (β-hcg) in serum sample at screening visit. women that are postmenopausal (menopause≥12 consecutive months) or permanently sterilized will be considered as not having reproductive potential. * wocbp must have used effective contraception 14 days prior to screening and agree to use effective contraception continuously during the trial period, from 14 days prior to screening visit to 60 days after the last immunization. * wocbp must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during trial, starting from screening visit and continuously until 60 days after being given the last immunization. * men who are sexually active with a wocbp and have not had a vasectomy must agree to practice an effective form of contraception with their female partner of childbearing potential during the trial, starting from screening visit and continuously until 60 days after being given the last immunization. * men must be willing to refrain from sperm donation, starting from screening visit and continuously until 60 days after receiving the last immunization. for the elderly group (age ≥65 and ≤85) * male or female subjects ≥65 years old and ≤85 years old at screening visit * individuals who are in a health condition that can receive the investigational vaccine, at the time of entry into the trial as determined by medical history, physical examination (including vital signs, ecg) and eligibility screening tests (hematology, biochemistry and urinalysis) and clinical judgment of the investigator at screening visit. * the subject can provide with informed consent and signs and dates a written icf prior to the initiation of any trial procedures. * they must be able to understand and follow trial-related instructions. * they must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial. * negative in antibodies screening of sars-cov-2 (blood sample from fingertip). * no imaging features of covid-19 in chest ct. * axillary temperature ≤ 37.0ºc. * negative sars-cov-2 test in throat swabs by rt-pcr. * wocbp must have a negative serum β-hcg at screening visit. women that are postmenopausal (menopause ≥12 consecutive months) or permanently sterilized will be considered as not having reproductive potential. * wocbp must have used effective contraception 14 days prior to screening and agree to use effective contraception continuously during the trial period, from 14 days prior to screening visit to 60 days after the last immunization. * wocbp must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during trial, starting from screening visit and continuously until 60 days after being given the last immunization. * men who are sexually active with a wocbp and have not had a vasectomy must agree to practice an effective form of contraception with their female partner of childbearing potential during the trial, starting from screening visit and continuously until 60 days after being given the last immunization. * men must be willing to refrain from sperm donation, starting from screening visit and continuously until 60 days after receiving the last immunization.

inclusion criteria: for adult group (age ≥18 and ≤55) - male or female subjects of ≥18 years old and ≤55 years old with body mass index (bmi) ≥18 and ≤30 at the screening visit. - individuals who are in good health condition at the time of entry into the trial as determined by medical history, physical examination (including vital signs, electrocardiogram [ecg]) and eligibility screening test (hematology, blood chemistry and urine analysis) and clinical judgment of the investigator at screening visit. - the subject can provide with informed consent and signs and dates a written informed consent form (icf) prior to the initiation of any trial procedures. - they must be able to understand and follow trial-related instructions. - they must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial. - negative in antibodies screening of sars-cov-2 (fingerstick). - normal in chest computed tomography (ct) scans (no imaging features of covid-19). - axillary temperature ≤ 37.0ºc. - negative sars-cov-2 test in throat swabs by reverse transcription-polymerase chain reaction (rt-pcr). - women of childbearing potential (wocbp) must have a negative beta-human chorionic gonadotropin (β-hcg) in serum sample at screening visit. women that are postmenopausal (menopause≥12 consecutive months) or permanently sterilized will be considered as not having reproductive potential. - wocbp must have used effective contraception 14 days prior to screening and agree to use effective contraception continuously during the trial period, from 14 days prior to screening visit to 60 days after the last immunization. - wocbp must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during trial, starting from screening visit and continuously until 60 days after being given the last immunization. - men who are sexually active with a wocbp and have not had a vasectomy must agree to practice an effective form of contraception with their female partner of childbearing potential during the trial, starting from screening visit and continuously until 60 days after being given the last immunization. - men must be willing to refrain from sperm donation, starting from screening visit and continuously until 60 days after receiving the last immunization. for the elderly group (age ≥65 and ≤85) - male or female subjects ≥65 years old and ≤85 years old at screening visit - individuals who are in a health condition that can receive the investigational vaccine, at the time of entry into the trial as determined by medical history, physical examination (including vital signs, ecg) and eligibility screening tests (hematology, biochemistry and urinalysis) and clinical judgment of the investigator at screening visit. - the subject can provide with informed consent and signs and dates a written icf prior to the initiation of any trial procedures. - they must be able to understand and follow trial-related instructions. - they must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial. - negative in antibodies screening of sars-cov-2 (blood sample from fingertip). - no imaging features of covid-19 in chest ct. - axillary temperature ≤ 37.0ºc. - negative sars-cov-2 test in throat swabs by rt-pcr. - wocbp must have a negative serum β-hcg at screening visit. women that are postmenopausal (menopause ≥12 consecutive months) or permanently sterilized will be considered as not having reproductive potential. - wocbp must have used effective contraception 14 days prior to screening and agree to use effective contraception continuously during the trial period, from 14 days prior to screening visit to 60 days after the last immunization. - wocbp must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during trial, starting from screening visit and continuously until 60 days after being given the last immunization. - men who are sexually active with a wocbp and have not had a vasectomy must agree to practice an effective form of contraception with their female partner of childbearing potential during the trial, starting from screening visit and continuously until 60 days after being given the last immunization. - men must be willing to refrain from sperm donation, starting from screening visit and continuously until 60 days after receiving the last immunization.

inclusion criteria: for adult group (age ≥18 and ≤55) - male or female subjects of ≥18 years old and ≤55 years old with body mass index (bmi) ≥18 and ≤30 at the screening visit. - individuals who are in good health condition at the time of entry into the trial as determined by medical history, physical examination (including vital signs, electrocardiogram [ecg]) and eligibility screening test (hematology, blood chemistry and urine analysis) and clinical judgment of the investigator at screening visit. - the subject can provide with informed consent and signs and dates a written informed consent form (icf) prior to the initiation of any trial procedures. - they must be able to understand and follow trial-related instructions. - they must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial. - negative in antibodies screening of sars-cov-2 (fingerstick). - normal in chest computed tomography (ct) scans (no imaging features of covid-19). - axillary temperature ≤ 37.0ºc. - negative sars-cov-2 test in throat swabs by reverse transcription-polymerase chain reaction (rt-pcr). - women of childbearing potential (wocbp) must have a negative beta-human chorionic gonadotropin (β-hcg) in serum sample at screening visit. women that are postmenopausal (menopause≥12 consecutive months) or permanently sterilized will be considered as not having reproductive potential. - wocbp must have used effective contraception 14 days prior to screening and agree to use effective contraception continuously during the trial period, from 14 days prior to screening visit to 60 days after the last immunization. - wocbp must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during trial, starting from screening visit and continuously until 60 days after being given the last immunization. - men who are sexually active with a wocbp and have not had a vasectomy must agree to practice an effective form of contraception with their female partner of childbearing potential during the trial, starting from screening visit and continuously until 60 days after being given the last immunization. - men must be willing to refrain from sperm donation, starting from screening visit and continuously until 60 days after receiving the last immunization. for the elderly group (age ≥65 and ≤85) - male or female subjects ≥65 years old and ≤85 years old at screening visit - individuals who are in a health condition that can receive the investigational vaccine, at the time of entry into the trial as determined by medical history, physical examination (including vital signs, ecg) and eligibility screening tests (hematology, biochemistry and urinalysis) and clinical judgment of the investigator at screening visit. - the subject can provide with informed consent and signs and dates a written icf prior to the initiation of any trial procedures. - they must be able to understand and follow trial-related instructions. - they must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial. - negative in antibodies screening of sars-cov-2 (blood sample from fingertip). - no imaging features of covid-19 in chest ct. - axillary temperature ≤ 37.0ºc. - negative sars-cov-2 test in throat swabs by rt-pcr. - wocbp must have a negative serum β-hcg at screening visit. women that are postmenopausal (menopause ≥12 consecutive months) or permanently sterilized will be considered as not having reproductive potential. - wocbp must have used effective contraception 14 days prior to screening and agree to use effective contraception continuously during the trial period, from 14 days prior to screening visit to 60 days after the last immunization. - wocbp must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during trial, starting from screening visit and continuously until 60 days after being given the last immunization. - men who are sexually active with a wocbp and have not had a vasectomy must agree to practice an effective form of contraception with their female partner of childbearing potential during the trial, starting from screening visit and continuously until 60 days after being given the last immunization. - men must be willing to refrain from sperm donation, starting from screening visit and continuously until 60 days after receiving the last immunization.