main inclusion criteria: * give informed consent by signing the informed consent form (icf) sars cov 2 vaccination status for part 1: 1. vb10.2129 (c1): have received 2 or 3 doses of an approved mrna sars cov 2 vaccine, minimum 4.5 months (20 weeks) prior to visit 1. 2. vb10.2210 (c2): have received 2 doses (primary vaccination) or 3 (primary and boost) doses of an approved mrna sars cov 2 vaccine, minimum 8 weeks prior to visit 1. sars cov 2 vaccination status for part 2: vb10.2129 (c1) and vb10.2210 (c2) vaccination status prior to visit 1 will be decided based on data from part 1. * willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (eg, local law and regulations \[county specific lock down rules\] regarding covid-19), and other requirements of the study. * healthy, in the clinical judgement of the investigator, based on medical history, physical examination, 12-lead electrocardiogram (ecg), vital signs (systolic/diastolic blood pressure, pulse rate, body temperature, respiratory rate), and clinical laboratory tests (blood chemistry, haematology, and urine chemistry) at visit 0 (screening). * women of childbearing potential (wocbp) must have a negative pregnancy test and must agree to practice a highly effective form * agree not to be vaccinated with any other vaccine during the study until 28 days after receiving the last study vaccination * negative rtpcr-test for sars-cov-2 main

main inclusion criteria: * give informed consent by signing the informed consent form (icf) sars cov 2 vaccination status for part 1: 1. vb10.2129 (c1): have received 2 or 3 doses of an approved mrna sars cov 2 vaccine, minimum 4.5 months (20 weeks) prior to visit 1. 2. vb10.2210 (c2): have received 2 doses (primary vaccination) or 3 (primary and boost) doses of an approved mrna sars cov 2 vaccine, minimum 8 weeks prior to visit 1. sars cov 2 vaccination status for part 2: vb10.2129 (c1) and vb10.2210 (c2) vaccination status prior to visit 1 will be decided based on data from part 1. * willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (eg, local law and regulations \[county specific lock down rules\] regarding covid-19), and other requirements of the study. * healthy, in the clinical judgement of the investigator, based on medical history, physical examination, 12-lead electrocardiogram (ecg), vital signs (systolic/diastolic blood pressure, pulse rate, body temperature, respiratory rate), and clinical laboratory tests (blood chemistry, haematology, and urine chemistry) at visit 0 (screening). * women of childbearing potential (wocbp) must have a negative pregnancy test and must agree to practice a highly effective form * agree not to be vaccinated with any other vaccine during the study until 28 days after receiving the last study vaccination * negative rtpcr-test for sars-cov-2 main

main inclusion criteria: give informed consent by signing the informed consent form (icf) sars cov 2 vaccination status for part 1: vb10.2129 (c1): have received 2 or 3 doses of an approved mrna sars cov 2 vaccine, minimum 4.5 months (20 weeks) prior to visit 1. vb10.2210 (c2): have received 2 doses (primary vaccination) or 3 (primary and boost) doses of an approved mrna sars cov 2 vaccine, minimum 8 weeks prior to visit 1. sars cov 2 vaccination status for part 2: vb10.2129 (c1) and vb10.2210 (c2) vaccination status prior to visit 1 will be decided based on data from part 1. willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (eg, local law and regulations [county specific lock down rules] regarding covid-19), and other requirements of the study. healthy, in the clinical judgement of the investigator, based on medical history, physical examination, 12-lead electrocardiogram (ecg), vital signs (systolic/diastolic blood pressure, pulse rate, body temperature, respiratory rate), and clinical laboratory tests (blood chemistry, haematology, and urine chemistry) at visit 0 (screening). women of childbearing potential (wocbp) must have a negative pregnancy test and must agree to practice a highly effective form agree not to be vaccinated with any other vaccine during the study until 28 days after receiving the last study vaccination negative rtpcr-test for sars-cov-2 main

main inclusion criteria: give informed consent by signing the informed consent form (icf) sars cov 2 vaccination status for part 1: vb10.2129 (c1): have received 2 or 3 doses of an approved mrna sars cov 2 vaccine, minimum 4.5 months (20 weeks) prior to visit 1. vb10.2210 (c2): have received 2 doses (primary vaccination) or 3 (primary and boost) doses of an approved mrna sars cov 2 vaccine, minimum 8 weeks prior to visit 1. sars cov 2 vaccination status for part 2: vb10.2129 (c1) and vb10.2210 (c2) vaccination status prior to visit 1 will be decided based on data from part 1. willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (eg, local law and regulations [county specific lock down rules] regarding covid-19), and other requirements of the study. healthy, in the clinical judgement of the investigator, based on medical history, physical examination, 12-lead electrocardiogram (ecg), vital signs (systolic/diastolic blood pressure, pulse rate, body temperature, respiratory rate), and clinical laboratory tests (blood chemistry, haematology, and urine chemistry) at visit 0 (screening). women of childbearing potential (wocbp) must have a negative pregnancy test and must agree to practice a highly effective form agree not to be vaccinated with any other vaccine during the study until 28 days after receiving the last study vaccination negative rtpcr-test for sars-cov-2 main

main inclusion criteria: give informed consent by signing the informed consent form (icf) sars cov 2 vaccination status for part 1: vb10.2129 (c1): have received 2 doses of an approved mrna sars cov 2 vaccine, minimum 6 months (26 weeks) prior to visit 1. vb10.2210 (c2): have received 2 doses (primary vaccination) or 3 (primary and boost) doses of an approved mrna sars cov 2 vaccine, minimum 8 weeks prior to visit 1. sars cov 2 vaccination status for part 2: vb10.2129 (c1) and vb10.2210 (c2) vaccination status prior to visit 1 will be decided based on data from part 1. willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (eg, local law and regulations [county specific lock down rules] regarding covid-19), and other requirements of the study. healthy, in the clinical judgement of the investigator, based on medical history, physical examination, 12-lead electrocardiogram (ecg), vital signs (systolic/diastolic blood pressure, pulse rate, body temperature, respiratory rate), and clinical laboratory tests (blood chemistry, haematology, and urine chemistry) at visit 0 (screening). women of childbearing potential (wocbp) must have a negative pregnancy test and must agree to practice a highly effective form agree not to be vaccinated with any other vaccine during the study until 28 days after receiving the last study vaccination negative rtpcr-test for sars-cov-2 main

main inclusion criteria: give informed consent by signing the informed consent form (icf) sars cov 2 vaccination status for part 1: vb10.2129 (c1): have received 2 doses of an approved mrna sars cov 2 vaccine, minimum 6 months (26 weeks) prior to visit 1. vb10.2210 (c2): have received 2 doses (primary vaccination) or 3 (primary and boost) doses of an approved mrna sars cov 2 vaccine, minimum 8 weeks prior to visit 1. sars cov 2 vaccination status for part 2: vb10.2129 (c1) and vb10.2210 (c2) vaccination status prior to visit 1 will be decided based on data from part 1. willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (eg, local law and regulations [county specific lock down rules] regarding covid-19), and other requirements of the study. healthy, in the clinical judgement of the investigator, based on medical history, physical examination, 12-lead electrocardiogram (ecg), vital signs (systolic/diastolic blood pressure, pulse rate, body temperature, respiratory rate), and clinical laboratory tests (blood chemistry, haematology, and urine chemistry) at visit 0 (screening). women of childbearing potential (wocbp) must have a negative pregnancy test and must agree to practice a highly effective form agree not to be vaccinated with any other vaccine during the study until 28 days after receiving the last study vaccination negative rtpcr-test for sars-cov-2 main

main inclusion criteria: - give informed consent by signing the informed consent form (icf) - part 1: have received 2 doses of an mrna sars-cov-2 vaccine, minimum 6 months prior to visit 1. - part 2: have received full vaccination schedule of an approved sars-cov-2 vaccine, minimum 6 months prior to visit 1. - willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (eg, local law and regulations [county specific lock down rules] regarding covid-19), and other requirements of the study. - healthy, in the clinical judgement of the investigator, based on medical history, physical examination, 12-lead electrocardiogram (ecg), vital signs (systolic/diastolic blood pressure, pulse rate, body temperature, respiratory rate), and clinical laboratory tests (blood chemistry, haematology, and urine chemistry) at visit 0 (screening). - women of childbearing potential (wocbp) must have a negative pregnancy test and must agree to practice a highly effective form - agree not to be vaccinated with any other vaccine during the study until 28 days after receiving the last study vaccination - negative rtpcr-test for sars-cov-2 main

main inclusion criteria: - give informed consent by signing the informed consent form (icf) - part 1: have received 2 doses of an mrna sars-cov-2 vaccine, minimum 6 months prior to visit 1. - part 2: have received full vaccination schedule of an approved sars-cov-2 vaccine, minimum 6 months prior to visit 1. - willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (eg, local law and regulations [county specific lock down rules] regarding covid-19), and other requirements of the study. - healthy, in the clinical judgement of the investigator, based on medical history, physical examination, 12-lead electrocardiogram (ecg), vital signs (systolic/diastolic blood pressure, pulse rate, body temperature, respiratory rate), and clinical laboratory tests (blood chemistry, haematology, and urine chemistry) at visit 0 (screening). - women of childbearing potential (wocbp) must have a negative pregnancy test and must agree to practice a highly effective form - agree not to be vaccinated with any other vaccine during the study until 28 days after receiving the last study vaccination - negative rtpcr-test for sars-cov-2 main