inclusion criteria: - each subject must meet all of the following criteria in order to participate in this study: 1. male or non-pregnant female 18 through 65 years of age at the time of first vaccination. 2. known clinical and immunization status versus sars-cov-2. 1. for cohort 3 participants this will be either no history of covid-19 nor reported history of vaccination against covid-19 by emergency use authorization (eua) vaccine or investigational product. 2. for cohort 1 and cohort 2 participants, this will be verified receipt of investigational or emergency use authorization (eua) vaccines against sars-cov-2 (by provision of either access to medical records, washington state online vaccine registry, documentation of receipt of investigational vaccine, or vaccine card), with most recent vaccination 90 days or more prior to trial initiation (days of immunization will be noted, along with vaccine manufacturer). 3. understands and agrees to comply with the study procedures and provides written informed consent. 4. in the opinion of the pi or designee, could and would comply with the requirements of the protocol (e.g., completion of memory aids, return for follow-up visits, availability for safety calls). 5. body mass index ≥18.0 and ≤35.0 kg/m2. 6. considered by the pi or designee to be in good general health as determined by medical history, clinical laboratory assessments, vital sign measurements, and physical examination findings at screening. 7. women of childbearing potential1 must agree to use or have practiced true abstinence or use at least one acceptable primary form of contraception. these criteria are applicable to females in a heterosexual relationship and of childbearing potential (i.e., the criteria do not apply to subjects in a same sex relationship). 8. female subjects of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test on the day of and prior to each study vaccination. 9. must agree to refrain from donating blood or plasma during the study (outside of this study).

inclusion criteria: - each subject must meet all of the following criteria in order to participate in this study: 1. male or non-pregnant female 18 through 65 years of age at the time of first vaccination. 2. known clinical and immunization status versus sars-cov-2. 1. for cohort 3 participants this will be either no history of covid-19 nor reported history of vaccination against covid-19 by emergency use authorization (eua) vaccine or investigational product. 2. for cohort 1 and cohort 2 participants, this will be verified receipt of investigational or emergency use authorization (eua) vaccines against sars-cov-2 (by provision of either access to medical records, washington state online vaccine registry, documentation of receipt of investigational vaccine, or vaccine card), with most recent vaccination 90 days or more prior to trial initiation (days of immunization will be noted, along with vaccine manufacturer). 3. understands and agrees to comply with the study procedures and provides written informed consent. 4. in the opinion of the pi or designee, could and would comply with the requirements of the protocol (e.g., completion of memory aids, return for follow-up visits, availability for safety calls). 5. body mass index ≥18.0 and ≤35.0 kg/m2. 6. considered by the pi or designee to be in good general health as determined by medical history, clinical laboratory assessments, vital sign measurements, and physical examination findings at screening. 7. women of childbearing potential1 must agree to use or have practiced true abstinence or use at least one acceptable primary form of contraception. these criteria are applicable to females in a heterosexual relationship and of childbearing potential (i.e., the criteria do not apply to subjects in a same sex relationship). 8. female subjects of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test on the day of and prior to each study vaccination. 9. must agree to refrain from donating blood or plasma during the study (outside of this study).

inclusion criteria: - each subject must meet all of the following criteria in order to participate in this study: male or non-pregnant female 18 through 65 years of age at the time of first vaccination. known clinical and immunization status versus sars-cov-2. for cohort 3 participants this will be either no history of covid-19 nor reported history of vaccination against covid-19 by emergency use authorization (eua) vaccine or investigational product. for cohort 1 and cohort 2 participants, this will be verified receipt of investigational or emergency use authorization (eua) vaccines against sars-cov-2 (by provision of either access to medical records, washington state online vaccine registry, documentation of receipt of investigational vaccine, or vaccine card), with most recent vaccination 90 days or more prior to trial initiation (days of immunization will be noted, along with vaccine manufacturer). understands and agrees to comply with the study procedures and provides written informed consent. in the opinion of the pi or designee, could and would comply with the requirements of the protocol (e.g., completion of memory aids, return for follow-up visits, availability for safety calls). body mass index ≥18.0 and ≤35.0 kg/m2. considered by the pi or designee to be in good general health as determined by medical history, clinical laboratory assessments, vital sign measurements, and physical examination findings at screening. women of childbearing potential1 must agree to use or have practiced true abstinence or use at least one acceptable primary form of contraception. these criteria are applicable to females in a heterosexual relationship and of childbearing potential (i.e., the criteria do not apply to subjects in a same sex relationship). female subjects of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test on the day of and prior to each study vaccination. must agree to refrain from donating blood or plasma during the study (outside of this study).

inclusion criteria: - each subject must meet all of the following criteria in order to participate in this study: male or non-pregnant female 18 through 65 years of age at the time of first vaccination. known clinical and immunization status versus sars-cov-2. for cohort 3 participants this will be either no history of covid-19 nor reported history of vaccination against covid-19 by emergency use authorization (eua) vaccine or investigational product. for cohort 1 and cohort 2 participants, this will be verified receipt of investigational or emergency use authorization (eua) vaccines against sars-cov-2 (by provision of either access to medical records, washington state online vaccine registry, documentation of receipt of investigational vaccine, or vaccine card), with most recent vaccination 90 days or more prior to trial initiation (days of immunization will be noted, along with vaccine manufacturer). understands and agrees to comply with the study procedures and provides written informed consent. in the opinion of the pi or designee, could and would comply with the requirements of the protocol (e.g., completion of memory aids, return for follow-up visits, availability for safety calls). body mass index ≥18.0 and ≤35.0 kg/m2. considered by the pi or designee to be in good general health as determined by medical history, clinical laboratory assessments, vital sign measurements, and physical examination findings at screening. women of childbearing potential1 must agree to use or have practiced true abstinence or use at least one acceptable primary form of contraception. these criteria are applicable to females in a heterosexual relationship and of childbearing potential (i.e., the criteria do not apply to subjects in a same sex relationship). female subjects of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test on the day of and prior to each study vaccination. must agree to refrain from donating blood or plasma during the study (outside of this study).