inclusion criteria: a participant must meet all the following criteria to be eligible for the study: 1. adults ages 18 years and older 2. judged by the investigator to be healthy based on participant-reported medical history, physical examination, vital signs, and laboratory assessment. 3. able to provide written informed consent. 4. willing to disclose prior covid-19 vaccination status. 5. willing to disclose prior participant-reported sars-cov-2 infection status. 6. willing to comply with all study procedures during the follow-up period of approximately 12 months. 7. body mass index of ≤ 40 kg/m2 within 30 days prior to enrollment 8. electrocardiogram (ecg) without clinically significant abnormalities. 9. clinical screening laboratory evaluations (i.e., cbc, iron, ferritin, tibc, platelets, alt, ast, creatinine) are within acceptable normal reference ranges at the clinical laboratory being used or are not deemed clinically significant by study clinician. for participants of childbearing potential: 10. negative beta-human chorionic gonadotropin (β-hcg) pregnancy test (urine or serum) on the day of enrollment 11. must agree to avoid pregnancy from 21 days prior to study day 1 until at least 90 days after last study vaccination.

inclusion criteria: a participant must meet all the following criteria to be eligible for the study: 1. adults ages 18 years and older 2. judged by the investigator to be healthy based on participant-reported medical history, physical examination, vital signs, and laboratory assessment. 3. able to provide written informed consent. 4. willing to disclose prior covid-19 vaccination status. 5. willing to disclose prior participant-reported sars-cov-2 infection status. 6. willing to comply with all study procedures during the follow-up period of approximately 12 months. 7. body mass index of ≤ 40 kg/m2 within 30 days prior to enrollment 8. electrocardiogram (ecg) without clinically significant abnormalities. 9. clinical screening laboratory evaluations (i.e., cbc, iron, ferritin, tibc, platelets, alt, ast, creatinine) are within acceptable normal reference ranges at the clinical laboratory being used or are not deemed clinically significant by study clinician. for participants of childbearing potential: 10. negative beta-human chorionic gonadotropin (β-hcg) pregnancy test (urine or serum) on the day of enrollment 11. must agree to avoid pregnancy from 21 days prior to study day 1 until at least 90 days after last study vaccination.

inclusion criteria: a participant must meet all the following criteria to be eligible for the study: adults ages 18 years and older judged by the investigator to be healthy based on participant-reported medical history, physical examination, vital signs, and laboratory assessment. able to provide written informed consent. willing to disclose prior covid-19 vaccination status. willing to disclose prior participant-reported sars-cov-2 infection status. willing to comply with all study procedures during the follow-up period of approximately 12 months. body mass index of ≤ 40 kg/m2 within 30 days prior to enrollment electrocardiogram (ecg) without clinically significant abnormalities. clinical screening laboratory evaluations (i.e., cbc, iron, ferritin, tibc, platelets, alt, ast, creatinine) are within acceptable normal reference ranges at the clinical laboratory being used or are not deemed clinically significant by study clinician. for participants of childbearing potential: negative beta-human chorionic gonadotropin (β-hcg) pregnancy test (urine or serum) on the day of enrollment must agree to avoid pregnancy from 21 days prior to study day 1 until at least 90 days after last study vaccination.

inclusion criteria: a participant must meet all the following criteria to be eligible for the study: adults ages 18 years and older judged by the investigator to be healthy based on participant-reported medical history, physical examination, vital signs, and laboratory assessment. able to provide written informed consent. willing to disclose prior covid-19 vaccination status. willing to disclose prior participant-reported sars-cov-2 infection status. willing to comply with all study procedures during the follow-up period of approximately 12 months. body mass index of ≤ 40 kg/m2 within 30 days prior to enrollment electrocardiogram (ecg) without clinically significant abnormalities. clinical screening laboratory evaluations (i.e., cbc, iron, ferritin, tibc, platelets, alt, ast, creatinine) are within acceptable normal reference ranges at the clinical laboratory being used or are not deemed clinically significant by study clinician. for participants of childbearing potential: negative beta-human chorionic gonadotropin (β-hcg) pregnancy test (urine or serum) on the day of enrollment must agree to avoid pregnancy from 21 days prior to study day 1 until at least 90 days after last study vaccination.