1. Age = 18 years on Study Day 0. 2. Judged by the investigator to be healthy on the basis of medical history, physical examination and vital signs performed at screening. 3. Able to provide informed consent form. 4. Able and willing to comply with all study procedures over follow-up period of approximately 14 months. 5. Axillary body temperature = 37.0?. 6. Sars-cov-2 test was negative for throat swabs by RT-PCR. 7. Female of non-pregnancy (negative pregnancy test), non-lactation. 8. For female subjects with childbearing potential: must agree to avoid pregnancy starting after screening until 90 days after receiving the last vaccination. Women physically capable of pregnancy (not sterilized and still menstruating or within 1 year of the last menses if menopausal) in sexual relationships with men must use an acceptable method of avoiding pregnancy during this period. Acceptable methods of avoiding pregnancy include a sterile sexual partner, sexual abstinence (not engaging in sexual intercourse), hormonal contraceptives (oral, injection, transdermal patch, or implant), vaginal ring, intrauterine device (IUD), or the combination of a condom or diaphragm with spermicide. 9. Male subjects who are sexually active with a woman of childbearing potential and have not had vasectomy must agree to practice a highly effective form of contraception with their female partners of childbearing potential during the trial, starting after screening until 90 days after receiving the last vaccination. 10. Men must be willing to refrain from sperm donation, starting after screening until 90 days after receiving the last vaccination.

1. Age = 18 years on Study Day 0. 2. Judged by the investigator to be healthy on the basis of medical history, physical examination and vital signs performed at screening. 3. Able to provide informed consent form. 4. Able and willing to comply with all study procedures over follow-up period of approximately 14 months. 5. Axillary body temperature = 37.0?. 6. Sars-cov-2 test was negative for throat swabs by RT-PCR. 7. Female of non-pregnancy (negative pregnancy test), non-lactation. 8. For female subjects with childbearing potential: must agree to avoid pregnancy starting after screening until 90 days after receiving the last vaccination. Women physically capable of pregnancy (not sterilized and still menstruating or within 1 year of the last menses if menopausal) in sexual relationships with men must use an acceptable method of avoiding pregnancy during this period. Acceptable methods of avoiding pregnancy include a sterile sexual partner, sexual abstinence (not engaging in sexual intercourse), hormonal contraceptives (oral, injection, transdermal patch, or implant), vaginal ring, intrauterine device (IUD), or the combination of a condom or diaphragm with spermicide. 9. Male subjects who are sexually active with a woman of childbearing potential and have not had vasectomy must agree to practice a highly effective form of contraception with their female partners of childbearing potential during the trial, starting after screening until 90 days after receiving the last vaccination. 10. Men must be willing to refrain from sperm donation, starting after screening until 90 days after receiving the last vaccination.