inclusion criteria: 1. male or female ≥18 years of age. 2. individuals are willing and able to comply with study requirements, including all scheduled visits, vaccinations, laboratory tests and other study procedures. 3. individuals are willing and able to give an informed consent, prior to screening. 4. healthy participants or participants with pre-existing medical conditions who are in a stable medical condition. (a stable medical condition is defined as medication not requiring major change for specific past medical condition, not receive surgery or minimal invasive medical intervention, and without hospitalization or er visit during the 3 months before enrollment.) 5. female participants of childbearing potential may be enrolled in the study, if the participant has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination and has agreed to continue adequate contraception for 6 months after the last vaccination. 6. male participants must agree to employ acceptable contraception from the day of the first dose of the study vaccine/placebo until 6 months after the last dose of the study vaccine/placebo and also refrain from donating sperm during this period.

inclusion criteria: 1. male or female ≥18 years of age. 2. individuals are willing and able to comply with study requirements, including all scheduled visits, vaccinations, laboratory tests and other study procedures. 3. individuals are willing and able to give an informed consent, prior to screening. 4. healthy participants or participants with pre-existing medical conditions who are in a stable medical condition. (a stable medical condition is defined as medication not requiring major change for specific past medical condition, not receive surgery or minimal invasive medical intervention, and without hospitalization or er visit during the 3 months before enrollment.) 5. female participants of childbearing potential may be enrolled in the study, if the participant has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination and has agreed to continue adequate contraception for 6 months after the last vaccination. 6. male participants must agree to employ acceptable contraception from the day of the first dose of the study vaccine/placebo until 6 months after the last dose of the study vaccine/placebo and also refrain from donating sperm during this period.

inclusion criteria: male or female ≥18 years of age. individuals are willing and able to comply with study requirements, including all scheduled visits, vaccinations, laboratory tests and other study procedures. individuals are willing and able to give an informed consent, prior to screening. healthy participants or participants with pre-existing medical conditions who are in a stable medical condition. (a stable medical condition is defined as medication not requiring major change for specific past medical condition, not receive surgery or minimal invasive medical intervention, and without hospitalization or er visit during the 3 months before enrollment.) female participants of childbearing potential may be enrolled in the study, if the participant has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination and has agreed to continue adequate contraception for 6 months after the last vaccination. male participants must agree to employ acceptable contraception from the day of the first dose of the study vaccine/placebo until 6 months after the last dose of the study vaccine/placebo and also refrain from donating sperm during this period.

inclusion criteria: male or female ≥18 years of age. individuals are willing and able to comply with study requirements, including all scheduled visits, vaccinations, laboratory tests and other study procedures. individuals are willing and able to give an informed consent, prior to screening. healthy participants or participants with pre-existing medical conditions who are in a stable medical condition. (a stable medical condition is defined as medication not requiring major change for specific past medical condition, not receive surgery or minimal invasive medical intervention, and without hospitalization or er visit during the 3 months before enrollment.) female participants of childbearing potential may be enrolled in the study, if the participant has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination and has agreed to continue adequate contraception for 6 months after the last vaccination. male participants must agree to employ acceptable contraception from the day of the first dose of the study vaccine/placebo until 6 months after the last dose of the study vaccine/placebo and also refrain from donating sperm during this period.

inclusion criteria: 1. male or female ≥18 years of age. 2. individuals are willing and able to comply with study requirements, including all scheduled visits, vaccinations, laboratory tests and other study procedures. 3. individuals are willing and able to give an informed consent, prior to screening. 4. healthy participants or participants with pre-existing medical conditions who are in a stable medical condition. (a stable medical condition is defined as medication not requiring major change for specific past medical condition, not receive surgery or minimal invasive medical intervention, and without hospitalization or er visit during the 3 months before enrollment.) 5. female participants of childbearing potential may be enrolled in the study, if the participant has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination and has agreed to continue adequate contraception for 6 months after the last vaccination. 6. male participants must agree to employ acceptable contraception from the day of the first dose of the study vaccine/placebo until 6 months after the last dose of the study vaccine/placebo and also refrain from donating sperm during this period.

inclusion criteria: 1. male or female ≥18 years of age. 2. individuals are willing and able to comply with study requirements, including all scheduled visits, vaccinations, laboratory tests and other study procedures. 3. individuals are willing and able to give an informed consent, prior to screening. 4. healthy participants or participants with pre-existing medical conditions who are in a stable medical condition. (a stable medical condition is defined as medication not requiring major change for specific past medical condition, not receive surgery or minimal invasive medical intervention, and without hospitalization or er visit during the 3 months before enrollment.) 5. female participants of childbearing potential may be enrolled in the study, if the participant has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination and has agreed to continue adequate contraception for 6 months after the last vaccination. 6. male participants must agree to employ acceptable contraception from the day of the first dose of the study vaccine/placebo until 6 months after the last dose of the study vaccine/placebo and also refrain from donating sperm during this period.