1. Male or female subjects aged 18 to 55 years old with body mass index (BMI) 18 to 30 at the Screening Visit. For the elderly subjects, aged >55 years old at Screening Visit, 2. 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, ECG) and eligibility screening test (hematology, blood chemistry and urine analysis) and clinical judgment of the investigator at Screening Visit. For the elderly subjects, individuals who are in a health condition that can receive the investigation vaccine, 3. 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, 4. They must be able to understand and follow trial-related instructions, 5. They must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial, 6. Negative in antibodies screening of SARS-CoV-2 (fingerstick), 7. Normal in chest CT scans (no imaging features of COVID-19). For the elderly subjects, No imaging features of COVID-19 in chest CT, 8. Axillary temperature <=37.0 degree C, 9. Negative SARS-CoV-2 test in throat swabs by RT-PCR, 10. Women of childbearing potential (WOCBP) must have a negative beta-human chorionic gonadotropin (beta-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, 11. 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, 12. 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 be given the last immunization, 13. Men who are sexually active with a WOCBP and have not had a vasectomy must agree to practice a effective form of contraception with their female partner of childbearing potential during the trial, starting from Screening Visit and continuously until 60 days after be given the last immunization, 14. Men must be willing to refrain from sperm donation, starting from Screening Visit and continuously until 60 days after receiving the last immunization.

1. Male or female subjects aged 18 to 55 years old with body mass index (BMI) 18 to 30 at the Screening Visit. For the elderly subjects, aged >55 years old at Screening Visit, 2. 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, ECG) and eligibility screening test (hematology, blood chemistry and urine analysis) and clinical judgment of the investigator at Screening Visit. For the elderly subjects, individuals who are in a health condition that can receive the investigation vaccine, 3. 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, 4. They must be able to understand and follow trial-related instructions, 5. They must be willing and able to comply with planned visits, treatment schedule, laboratory tests and other requirements of the trial, 6. Negative in antibodies screening of SARS-CoV-2 (fingerstick), 7. Normal in chest CT scans (no imaging features of COVID-19). For the elderly subjects, No imaging features of COVID-19 in chest CT, 8. Axillary temperature <=37.0 degree C, 9. Negative SARS-CoV-2 test in throat swabs by RT-PCR, 10. Women of childbearing potential (WOCBP) must have a negative beta-human chorionic gonadotropin (beta-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, 11. 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, 12. 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 be given the last immunization, 13. Men who are sexually active with a WOCBP and have not had a vasectomy must agree to practice a effective form of contraception with their female partner of childbearing potential during the trial, starting from Screening Visit and continuously until 60 days after be given the last immunization, 14. Men must be willing to refrain from sperm donation, starting from Screening Visit and continuously until 60 days after receiving the last immunization.