inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are men or non-pregnant women aged 18 years or older at enrollment 4. are in good health\* \*as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination (pe), screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)\* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception\*\* consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. \*not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or \< 1 year has passed since the last menses if menopausal \*\*acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: * pulse \> 50 and = / \< 100 beats per minute * systolic blood pressure (bp) = / \< 140 millimeters of mercury (mmhg) * diastolic bp = / \< 90 mmhg * oral temperature \< 37.8 degrees celsius (100.0 degrees fahrenheit) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used\* \*with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. 11. must agree to genetic testing and storage of samples for secondary research 12. received at least 2 doses of eua/licensed mrna vaccines or at least 1 dose of ad26 vaccine followed by an mrna booster, with the last covid-19 vaccine dose given at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation. subjects may or may not have been previously infected with sars-cov-2. a subject must meet all of the following criteria to be eligible for leukapheresis: 1. written informed consent for leukapheresis is provided 2. weight \> / = 110 pounds 3. screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed 4. negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential 5. adequate bilateral antecubital venous access 6. no use of blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are men or non-pregnant women aged 18 years or older at enrollment 4. are in good health\* \*as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination (pe), screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)\* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception\*\* consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. \*not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or \< 1 year has passed since the last menses if menopausal \*\*acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: * pulse \> 50 and = / \< 100 beats per minute * systolic blood pressure (bp) = / \< 140 millimeters of mercury (mmhg) * diastolic bp = / \< 90 mmhg * oral temperature \< 37.8 degrees celsius (100.0 degrees fahrenheit) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used\* \*with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. 11. must agree to genetic testing and storage of samples for secondary research 12. received at least 2 doses of eua/licensed mrna vaccines or at least 1 dose of ad26 vaccine followed by an mrna booster, with the last covid-19 vaccine dose given at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation. subjects may or may not have been previously infected with sars-cov-2. a subject must meet all of the following criteria to be eligible for leukapheresis: 1. written informed consent for leukapheresis is provided 2. weight \> / = 110 pounds 3. screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed 4. negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential 5. adequate bilateral antecubital venous access 6. no use of blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: provide written informed consent prior to initiation of any study procedures able and willing (in the investigator's opinion) to comply with all study requirements are men or non-pregnant women aged 18 years or older at enrollment are in good health* *as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination (pe), screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. agree to refrain from blood donation during the course of the study plan to remain living in the area for the duration of the study women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination vital signs within acceptable ranges: pulse > 50 and = / < 100 beats per minute systolic blood pressure (bp) = / < 140 millimeters of mercury (mmhg) diastolic bp = / < 90 mmhg oral temperature < 37.8 degrees celsius (100.0 degrees fahrenheit) clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used* *with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. must agree to genetic testing and storage of samples for secondary research received at least 2 doses of eua/licensed mrna vaccines or at least 1 dose of ad26 vaccine followed by an mrna booster, with the last covid-19 vaccine dose given at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation. subjects may or may not have been previously infected with sars-cov-2. a subject must meet all of the following criteria to be eligible for leukapheresis: written informed consent for leukapheresis is provided weight > / = 110 pounds screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential adequate bilateral antecubital venous access no use of blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: provide written informed consent prior to initiation of any study procedures able and willing (in the investigator's opinion) to comply with all study requirements are men or non-pregnant women aged 18 years or older at enrollment are in good health* *as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination (pe), screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. agree to refrain from blood donation during the course of the study plan to remain living in the area for the duration of the study women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination vital signs within acceptable ranges: pulse > 50 and = / < 100 beats per minute systolic blood pressure (bp) = / < 140 millimeters of mercury (mmhg) diastolic bp = / < 90 mmhg oral temperature < 37.8 degrees celsius (100.0 degrees fahrenheit) clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used* *with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. must agree to genetic testing and storage of samples for secondary research received at least 2 doses of eua/licensed mrna vaccines or at least 1 dose of ad26 vaccine followed by an mrna booster, with the last covid-19 vaccine dose given at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation. subjects may or may not have been previously infected with sars-cov-2. a subject must meet all of the following criteria to be eligible for leukapheresis: written informed consent for leukapheresis is provided weight > / = 110 pounds screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential adequate bilateral antecubital venous access no use of blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: provide written informed consent prior to initiation of any study procedures able and willing (in the investigator's opinion) to comply with all study requirements are men or non-pregnant women aged 18 years or older at enrollment are in good health* *as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination (pe), screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. agree to refrain from blood donation during the course of the study plan to remain living in the area for the duration of the study women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination vital signs within acceptable ranges: pulse > 50 and = / < 100 beats per minute systolic blood pressure (bp) = / < 140 millimeters of mercury (mmhg) diastolic bp = / < 90 mmhg oral temperature < 37.8 degrees celsius (100.0 degrees fahrenheit) clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used* *with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. must agree to genetic testing and storage of samples for secondary research received and completed covid-19 vaccine under emergency use authorization (eua) dosing guidelines at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation a subject must meet all of the following criteria to be eligible for leukapheresis: written informed consent for leukapheresis is provided weight > / = 110 pounds screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential adequate bilateral antecubital venous access no use of blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: provide written informed consent prior to initiation of any study procedures able and willing (in the investigator's opinion) to comply with all study requirements are men or non-pregnant women aged 18 years or older at enrollment are in good health* *as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination (pe), screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. agree to refrain from blood donation during the course of the study plan to remain living in the area for the duration of the study women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination vital signs within acceptable ranges: pulse > 50 and = / < 100 beats per minute systolic blood pressure (bp) = / < 140 millimeters of mercury (mmhg) diastolic bp = / < 90 mmhg oral temperature < 37.8 degrees celsius (100.0 degrees fahrenheit) clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used* *with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. must agree to genetic testing and storage of samples for secondary research received and completed covid-19 vaccine under emergency use authorization (eua) dosing guidelines at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation a subject must meet all of the following criteria to be eligible for leukapheresis: written informed consent for leukapheresis is provided weight > / = 110 pounds screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential adequate bilateral antecubital venous access no use of blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are men or non-pregnant women aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination (pe), screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - pulse > 50 and = / < 100 beats per minute - systolic blood pressure (bp) = / < 140 millimeters of mercury (mmhg) - diastolic bp = / < 90 mmhg - oral temperature < 37.8 degrees celsius (100.0 degrees fahrenheit) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used* *with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. 11. must agree to genetic testing and storage of samples for secondary research 12. received and completed covid-19 vaccine under emergency use authorization (eua) dosing guidelines at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation a subject must meet all of the following criteria to be eligible for leukapheresis: 1. written informed consent for leukapheresis is provided 2. weight > / = 110 pounds 3. screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed 4. negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential 5. adequate bilateral antecubital venous access 6. no use of blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are men or non-pregnant women aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination (pe), screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - pulse > 50 and = / < 100 beats per minute - systolic blood pressure (bp) = / < 140 millimeters of mercury (mmhg) - diastolic bp = / < 90 mmhg - oral temperature < 37.8 degrees celsius (100.0 degrees fahrenheit) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used* *with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. 11. must agree to genetic testing and storage of samples for secondary research 12. received and completed covid-19 vaccine under emergency use authorization (eua) dosing guidelines at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation a subject must meet all of the following criteria to be eligible for leukapheresis: 1. written informed consent for leukapheresis is provided 2. weight > / = 110 pounds 3. screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed 4. negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential 5. adequate bilateral antecubital venous access 6. no use of blood thinners, aspirin, or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are males or non-pregnant females aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination, screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - heart rate > 50 and = / < 100 beats per minute - systolic blood pressure = / < 140 millimeters of mercury (mmhg) - diastolic blood pressure = / < 90 mmhg - temperature < 37.8 degrees celsius (100.0 degrees fahrenheit) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used* *with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. 11. must agree to genetic testing and storage of samples for secondary research 12. received and completed covid-19 vaccine under eua dosing guidelines at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation a subject must meet all of the following criteria to be eligible for leukapheresis: 1. written informed consent for leukapheresis is provided 2. weight > / = 110 pounds 3. screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed 4. negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential 5. adequate bilateral antecubital venous access 6. no use of blood thinners, aspirin or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are males or non-pregnant females aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the cdc as increasing risk for severe corona virus disease-19 (covid-19) (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination, screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). any prescription change that is due to change of health care provider, insurance company, etc., or done for financial reasons, and in the same class of medication, will not be considered a deviation of this inclusion criterion. any change in prescription medication due to improvement of a disease outcome, as determined by the participating site pi or appropriate sub- investigator, will not be considered a deviation of this inclusion criterion. subjects may be on chronic or as needed (prn) medications if, in the opinion of the participating site pi or appropriate sub-investigator, they pose no additional risk to subject safety or assessment of reactogenicity and immunogenicity, and do not indicate a worsening of medical diagnosis/condition. similarly, medication changes in the 60 days prior to enrollment as well as subsequent to enrollment and study vaccination are acceptable provided the change was not precipitated by deterioration in the chronic medical condition, and there is no anticipated additional risk to the subject or interference with the evaluation of responses to study vaccination. 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - heart rate > 50 and = / < 100 beats per minute - systolic blood pressure = / < 140 millimeters of mercury (mmhg) - diastolic blood pressure = / < 90 mmhg - temperature < 37.8 degrees celsius (100.0 degrees fahrenheit) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used* *with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment. 11. must agree to genetic testing and storage of samples for secondary research 12. received and completed covid-19 vaccine under eua dosing guidelines at least 112 days prior to enrollment (stage 2 only), as confirmed via cdc vaccination card or other appropriate documentation a subject must meet all of the following criteria to be eligible for leukapheresis: 1. written informed consent for leukapheresis is provided 2. weight > / = 110 pounds 3. screening laboratory evaluations are within acceptable ranges at the site where the leukapheresis procedure will be performed 4. negative urine or serum pregnancy test at screening and on the day of the leukapheresis procedure for women of childbearing potential 5. adequate bilateral antecubital venous access 6. no use of blood thinners, aspirin or nonsteroidal anti-inflammatory drugs (nsaids) at least 5 days before the leukapheresis procedure

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are males or non-pregnant females aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the centers for disease control and prevention (cdc) as increasing risk for severe coronavirus disease 2019 (covid-19) disease (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination, screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). this includes no change in chronic prescription medications in the 60 days prior to enrollment 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - heart rate > 50 and = / < 100 beats per minute - systolic blood pressure = / < 140 millimeters of mercury (mmhg) - diastolic blood pressure = / < 90 mmhg - temperature < 37.8°c (100.0°f) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase, (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used, with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment 11. must agree to genetic testing and storage of samples for secondary research

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are males or non-pregnant females aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the centers for disease control and prevention (cdc) as increasing risk for severe coronavirus disease 2019 (covid-19) disease (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination, screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). this includes no change in chronic prescription medications in the 60 days prior to enrollment 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - heart rate > 50 and = / < 100 beats per minute - systolic blood pressure = / < 140 millimeters of mercury (mmhg) - diastolic blood pressure = / < 90 mmhg - temperature < 37.8°c (100.0°f) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase, (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used, with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment 11. must agree to genetic testing and storage of samples for secondary research

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are males or non-pregnant females aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the centers for disease control and prevention (cdc) as increasing risk for severe coronavirus disease 2019 (covid-19) disease (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination, screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). this includes no change in chronic prescription medications in the 60 days prior to enrollment 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - heart rate > 50 and < 100 beats per minute - systolic blood pressure = / < 140 millimeters of mercury (mmhg) - diastolic blood pressure = / < 90 mmhg - temperature < 37.8°c (100.0°f) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase, (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used, with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment 11. must agree to genetic testing and storage of samples for secondary research

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are males or non-pregnant females aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the centers for disease control and prevention (cdc) as increasing risk for severe coronavirus disease 2019 (covid-19) disease (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination, screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). this includes no change in chronic prescription medications in the 60 days prior to enrollment 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - heart rate > 50 and < 100 beats per minute - systolic blood pressure = / < 140 millimeters of mercury (mmhg) - diastolic blood pressure = / < 90 mmhg - temperature < 37.8°c (100.0°f) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatine kinase, (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used, with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment 11. must agree to genetic testing and storage of samples for secondary research

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are males or non-pregnant females aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the centers for disease control and prevention (cdc) as increasing risk for severe coronavirus disease 2019 (covid-19) disease (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination, screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). this includes no change in chronic prescription medications in the 60 days prior to enrollment 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - heart rate > 50 and < 100 beats per minute - systolic blood pressure = / < 140 millimeters of mercury (mmhg) - diastolic blood pressure = / < 90 mmhg - temperature < 37.8°c (100.0°f) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatinine kinase, (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used, with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment 11. must agree to genetic testing and storage of samples for secondary research

inclusion criteria: subjects eligible to participate in this trial must meet all of the following inclusion criteria: 1. provide written informed consent prior to initiation of any study procedures 2. able and willing (in the investigator's opinion) to comply with all study requirements 3. are males or non-pregnant females aged 18 years or older at enrollment 4. are in good health* *as defined by absence of clinically significant medical conditions defined by the centers for disease control and prevention (cdc) as increasing risk for severe coronavirus disease 2019 (covid-19) disease (see exclusion criteria), or other acute or chronic medical conditions determined by medical history, physical examination, screening laboratory test results, and/or clinical assessment of the investigator that are either listed as exclusion criteria below or in the opinion of the investigator would increase risk for study participation or affect the assessment of the safety of subjects. chronic medical conditions should be stable for the last 60 days (no hospitalizations, emergency room or urgent care for condition, or invasive medical procedures). this includes no change in chronic prescription medications in the 60 days prior to enrollment 5. agree to refrain from blood donation during the course of the study 6. plan to remain living in the area for the duration of the study 7. women of childbearing potential (wocbp)* must plan to avoid pregnancy for at least 60 days after the last study vaccination and be willing to use an adequate method of contraception** consistently for 30 days prior to first study vaccine and for at least 60 days after the last study vaccine. *not sterilized via bilateral oophorectomy, tubal ligation/salpingectomy, hysterectomy, or successful essure (r) placement (permanent, non-surgical, non-hormonal sterilization with documented radiological confirmation test at least 90 days after the procedure); still menstruating; or < 1 year has passed since the last menses if menopausal **acceptable methods of birth control include the following: oral contraceptives, injection hormonal contraceptive, implant hormonal contraceptive, hormonal patch, intrauterine device, spermicidal products and barrier methods (such as cervical sponge, diaphragm, or condom with spermicide), abstinence, monogamous with a vasectomized partner, non-male sexual relationship 8. women of childbearing potential must have a negative urine or serum pregnancy test within 24 hours prior to each study vaccination 9. vital signs within acceptable ranges: - heart rate > 50 and < 100 beats per minute - systolic blood pressure = / < 140 millimeters of mercury (mmhg) - diastolic blood pressure = / < 90 mmhg - temperature < 37.8°c (100.0°f) 10. clinical screening lab evaluations (white blood cell (wbc), hemoglobin (hgb), platelets (plt), alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp), total bilirubin (t bili), creatinine kinase, (ck), serum creatinine (cr) and prothrombin time (pt)/partial thromboplastin time (ptt)) are within acceptable normal reference ranges at the clinical lab being used, with the exception that alt, ast, alp, and creatinine values that are below the reference range will not be exclusionary as these values below reference range are clinically insignificant. any other screening lab value outside the reference range that is thought to be clinically insignificant by a site investigator must be discussed with the dmid medical officer prior to enrollment 11. must agree to genetic testing and storage of samples for secondary research