inclusion criteria: - adults males or females between 18-39 years of age at the day of screening. - willing and able to comply with scheduled visits, laboratory test, complete diaries and other study procedures. - body mass index 18 to 40 kg/m2 at screening. - covid19 negative pcr test and negative serum igg binding antibody response to the sars-cov-2 s glycoprotein at screening or prior the first vaccination. - willing to avoid all other vaccines within 4 weeks before and after each injection. seasonal influenza vaccination is allowed if it is received at least 14 days before or after the vaccination. - women of childbearing potential must have a negative pregnancy test in urine before the inclusion of the study and prior to each vaccination. - if female of childbearing potential, willing to use highly effective contraceptive methods or have practiced sexual abstinence from the screening visit until 8 weeks after the last injection. - if male and not sterilized, willing to avoid impregnating female partners from screening until 18 weeks after last injection. - willing and able to provide written informed consent prior the initiation of any study procedures.

inclusion criteria: - adults males or females between 18-39 years of age at the day of screening. - willing and able to comply with scheduled visits, laboratory test, complete diaries and other study procedures. - body mass index 18 to 40 kg/m2 at screening. - covid19 negative pcr test and negative serum igg binding antibody response to the sars-cov-2 s glycoprotein at screening or prior the first vaccination. - willing to avoid all other vaccines within 4 weeks before and after each injection. seasonal influenza vaccination is allowed if it is received at least 14 days before or after the vaccination. - women of childbearing potential must have a negative pregnancy test in urine before the inclusion of the study and prior to each vaccination. - if female of childbearing potential, willing to use highly effective contraceptive methods or have practiced sexual abstinence from the screening visit until 8 weeks after the last injection. - if male and not sterilized, willing to avoid impregnating female partners from screening until 18 weeks after last injection. - willing and able to provide written informed consent prior the initiation of any study procedures.