inclusion criteria: 1. healthy adults, age ≥ 18 years, inclusive, at time of enrollment, that have previously received an fda-authorized covid-19 vaccine (both prime and boost) ≥14 days and ≤ 6 months before enrollment. 2. able to understand and provide a signed informed consent that fulfills the relevant institutional review board (irb) or independent ethics committee (iec) guidelines. 3. agrees to the collection of biospecimens (eg, np swabs and/or saliva sample) and venous blood per protocol. 4. ability to attend required study visits and return for adequate follow-up, as required by this protocol. 5. ability to swallow a capsule. 6. temperature \< 38°c. 7. agreement to practice effective contraception for female subjects of childbearing potential and non-sterile males. female subjects of childbearing potential must agree to use effective contraception while on study until at least 1 month after the last dose of vaccine. non-sterile male subjects must agree to use a condom while on study until at least 1 month after the last dose of vaccine. effective contraception includes surgical sterilization (eg, vasectomy, tubal ligation), two forms of barrier methods (eg, condom, diaphragm) used with spermicide, iuds, oral contraceptives, and abstinence.

inclusion criteria: 1. healthy adults, age ≥ 18 years, inclusive, at time of enrollment, that have previously received an fda-authorized covid-19 vaccine (both prime and boost) ≥14 days and ≤ 6 months before enrollment. 2. able to understand and provide a signed informed consent that fulfills the relevant institutional review board (irb) or independent ethics committee (iec) guidelines. 3. agrees to the collection of biospecimens (eg, np swabs and/or saliva sample) and venous blood per protocol. 4. ability to attend required study visits and return for adequate follow-up, as required by this protocol. 5. ability to swallow a capsule. 6. temperature \< 38°c. 7. agreement to practice effective contraception for female subjects of childbearing potential and non-sterile males. female subjects of childbearing potential must agree to use effective contraception while on study until at least 1 month after the last dose of vaccine. non-sterile male subjects must agree to use a condom while on study until at least 1 month after the last dose of vaccine. effective contraception includes surgical sterilization (eg, vasectomy, tubal ligation), two forms of barrier methods (eg, condom, diaphragm) used with spermicide, iuds, oral contraceptives, and abstinence.

inclusion criteria: healthy adults, age ≥ 18 years, inclusive, at time of enrollment, that have previously received an fda-authorized covid-19 vaccine (both prime and boost) ≥14 days and ≤ 6 months before enrollment. able to understand and provide a signed informed consent that fulfills the relevant institutional review board (irb) or independent ethics committee (iec) guidelines. agrees to the collection of biospecimens (eg, np swabs and/or saliva sample) and venous blood per protocol. ability to attend required study visits and return for adequate follow-up, as required by this protocol. ability to swallow a capsule. temperature < 38°c. agreement to practice effective contraception for female subjects of childbearing potential and non-sterile males. female subjects of childbearing potential must agree to use effective contraception while on study until at least 1 month after the last dose of vaccine. non-sterile male subjects must agree to use a condom while on study until at least 1 month after the last dose of vaccine. effective contraception includes surgical sterilization (eg, vasectomy, tubal ligation), two forms of barrier methods (eg, condom, diaphragm) used with spermicide, iuds, oral contraceptives, and abstinence.

inclusion criteria: healthy adults, age ≥ 18 years, inclusive, at time of enrollment, that have previously received an fda-authorized covid-19 vaccine (both prime and boost) ≥14 days and ≤ 6 months before enrollment. able to understand and provide a signed informed consent that fulfills the relevant institutional review board (irb) or independent ethics committee (iec) guidelines. agrees to the collection of biospecimens (eg, np swabs and/or saliva sample) and venous blood per protocol. ability to attend required study visits and return for adequate follow-up, as required by this protocol. ability to swallow a capsule. temperature < 38°c. agreement to practice effective contraception for female subjects of childbearing potential and non-sterile males. female subjects of childbearing potential must agree to use effective contraception while on study until at least 1 month after the last dose of vaccine. non-sterile male subjects must agree to use a condom while on study until at least 1 month after the last dose of vaccine. effective contraception includes surgical sterilization (eg, vasectomy, tubal ligation), two forms of barrier methods (eg, condom, diaphragm) used with spermicide, iuds, oral contraceptives, and abstinence.

inclusion criteria: 1. healthy adults, age ≥ 18 years, inclusive, at time of enrollment, that have previously received an fda-authorized covid-19 vaccine (both prime and boost) ≥14 days and ≤ 6 months before enrollment. 2. able to understand and provide a signed informed consent that fulfills the relevant institutional review board (irb) or independent ethics committee (iec) guidelines. 3. agrees to the collection of biospecimens (eg, np swabs and/or saliva sample) and venous blood per protocol. 4. ability to attend required study visits and return for adequate follow-up, as required by this protocol. 5. ability to swallow a capsule. 6. temperature < 38°c. 7. agreement to practice effective contraception for female subjects of childbearing potential and non-sterile males. female subjects of childbearing potential must agree to use effective contraception while on study until at least 1 month after the last dose of vaccine. non-sterile male subjects must agree to use a condom while on study until at least 1 month after the last dose of vaccine. effective contraception includes surgical sterilization (eg, vasectomy, tubal ligation), two forms of barrier methods (eg, condom, diaphragm) used with spermicide, iuds, oral contraceptives, and abstinence.

inclusion criteria: 1. healthy adults, age ≥ 18 years, inclusive, at time of enrollment, that have previously received an fda-authorized covid-19 vaccine (both prime and boost) ≥14 days and ≤ 6 months before enrollment. 2. able to understand and provide a signed informed consent that fulfills the relevant institutional review board (irb) or independent ethics committee (iec) guidelines. 3. agrees to the collection of biospecimens (eg, np swabs and/or saliva sample) and venous blood per protocol. 4. ability to attend required study visits and return for adequate follow-up, as required by this protocol. 5. ability to swallow a capsule. 6. temperature < 38°c. 7. agreement to practice effective contraception for female subjects of childbearing potential and non-sterile males. female subjects of childbearing potential must agree to use effective contraception while on study until at least 1 month after the last dose of vaccine. non-sterile male subjects must agree to use a condom while on study until at least 1 month after the last dose of vaccine. effective contraception includes surgical sterilization (eg, vasectomy, tubal ligation), two forms of barrier methods (eg, condom, diaphragm) used with spermicide, iuds, oral contraceptives, and abstinence.