1. Adult males or females aged 18 to 84 years (inclusive) at screening. 2. Able and willing (in the investigator’s opinion) to comply with all study requirements. 3. Willing to allow the investigators to discuss the volunteer’s medical history with their General Practitioner and access all medical records when relevant to study procedures. 4. Willing and able to give informed consent prior to study enrolment. 5. Female participants of childbearing potential (defined as any female who has experienced menarche and who is NOT surgically sterile [i.e., hysterectomy, bilateral tubal ligation, or bilateral oophorectomy] or postmenopausal [defined as amenorrhea at least 12 consecutive months or > 1 documented plasma follicle-stimulating hormone level ≥ 40 mIU/mL]) must agree to be heterosexually inactive from at least 28 days prior to enrolment and through 3 months after the last study vaccination OR agree to consistently use any of the following methods of contraception from at least 28 days prior to enrolment and through 3 months after the last study vaccination: a. Condoms (male or female) b. Diaphragm with spermicide c. Cervical cap with spermicide d. Intrauterine device e. Oral or patch contraceptives f. Norplant®, Depo-Provera®, or other in country regulatory-approved contraceptive method that is designed to protect against pregnancy g. Abstinence, as a form of contraception, is acceptable if in line with the participant’s lifestyle (Other approaches to abstinence are not acceptable) NOTE: Periodic abstinence (e.g., calendar, ovulation, symptothermal, postovulation methods) and withdrawal are not acceptable methods of contraception. 6. Room air oxygen saturation >95% at Screening/Day 0 Seasonal Influenza Vaccine Co-Administration Sub-Study Only 7. Participant should not have received a current season influenza vaccine, have no contraindication to the specific vaccine to be administered in the study, and no prior history of allergy or severe reaction to seasonal influenza vaccines.

1. Adult males or females aged 18 to 84 years (inclusive) at screening. 2. Able and willing (in the investigator’s opinion) to comply with all study requirements. 3. Willing to allow the investigators to discuss the volunteer’s medical history with their General Practitioner and access all medical records when relevant to study procedures. 4. Willing and able to give informed consent prior to study enrolment. 5. Female participants of childbearing potential (defined as any female who has experienced menarche and who is NOT surgically sterile [i.e., hysterectomy, bilateral tubal ligation, or bilateral oophorectomy] or postmenopausal [defined as amenorrhea at least 12 consecutive months or > 1 documented plasma follicle-stimulating hormone level ≥ 40 mIU/mL]) must agree to be heterosexually inactive from at least 28 days prior to enrolment and through 3 months after the last study vaccination OR agree to consistently use any of the following methods of contraception from at least 28 days prior to enrolment and through 3 months after the last study vaccination: a. Condoms (male or female) b. Diaphragm with spermicide c. Cervical cap with spermicide d. Intrauterine device e. Oral or patch contraceptives f. Norplant®, Depo-Provera®, or other in country regulatory-approved contraceptive method that is designed to protect against pregnancy g. Abstinence, as a form of contraception, is acceptable if in line with the participant’s lifestyle (Other approaches to abstinence are not acceptable) NOTE: Periodic abstinence (e.g., calendar, ovulation, symptothermal, postovulation methods) and withdrawal are not acceptable methods of contraception. 6. Room air oxygen saturation >95% at Screening/Day 0 Seasonal Influenza Vaccine Co-Administration Sub-Study Only 7. Participant should not have received a current season influenza vaccine, have no contraindication to the specific vaccine to be administered in the study, and no prior history of allergy or severe reaction to seasonal influenza vaccines.

1. Adult males or females aged 18 to 84 years (inclusive) at screening. 2. Able and willing (in the investigator’s opinion) to comply with all study requirements. 3. Willing to allow the investigators to discuss the volunteer’s medical history with their General Practitioner and access all medical records when relevant to study procedures. 4. Willing and able to give informed consent prior to study enrolment. 5. Female participants of childbearing potential (defined as any female who has experienced menarche and who is NOT surgically sterile [i.e., hysterectomy, bilateral tubal ligation, or bilateral oophorectomy] or postmenopausal [defined as amenorrhea at least 12 consecutive months or > 1 documented plasma follicle-stimulating hormone level ≥ 40 mIU/mL]) must agree to be heterosexually inactive from at least 28 days prior to enrolment and through 3 months after the last study vaccination OR agree to consistently use any of the following methods of contraception from at least 28 days prior to enrolment and through 3 months after the last study vaccination: a. Condoms (male or female) with spermicide b. Diaphragm with spermicide c. Cervical cap with spermicide d. Intrauterine device e. Oral or patch contraceptives f. Norplant®, Depo-Provera®, or other in country regulatory-approved contraceptive method that is designed to protect against pregnancy g. Abstinence, as a form of contraception, is acceptable if in line with the participant’s lifestyle NOTE: Periodic abstinence (e.g., calendar, ovulation, symptothermal, postovulation methods) and withdrawal are not acceptable methods of contraception. Seasonal Influenza Vaccine Co-Administration Sub-Study Only 6. Participant should not have received a current season influenza vaccine, have no contraindication to the specific vaccine to be administered in the study, and no prior history of allergy or severe reaction to seasonal influenza vaccines.

1. Adult males or females aged 18 to 84 years (inclusive) at screening. 2. Able and willing (in the investigator’s opinion) to comply with all study requirements. 3. Willing to allow the investigators to discuss the volunteer’s medical history with their General Practitioner and access all medical records when relevant to study procedures. 4. Willing and able to give informed consent prior to study enrolment. 5. Female participants of childbearing potential (defined as any female who has experienced menarche and who is NOT surgically sterile [i.e., hysterectomy, bilateral tubal ligation, or bilateral oophorectomy] or postmenopausal [defined as amenorrhea at least 12 consecutive months or > 1 documented plasma follicle-stimulating hormone level ≥ 40 mIU/mL]) must agree to be heterosexually inactive from at least 28 days prior to enrolment and through 3 months after the last study vaccination OR agree to consistently use any of the following methods of contraception from at least 28 days prior to enrolment and through 3 months after the last study vaccination: a. Condoms (male or female) with spermicide b. Diaphragm with spermicide c. Cervical cap with spermicide d. Intrauterine device e. Oral or patch contraceptives f. Norplant®, Depo-Provera®, or other in country regulatory-approved contraceptive method that is designed to protect against pregnancy g. Abstinence, as a form of contraception, is acceptable if in line with the participant’s lifestyle NOTE: Periodic abstinence (e.g., calendar, ovulation, symptothermal, postovulation methods) and withdrawal are not acceptable methods of contraception. Seasonal Influenza Vaccine Co-Administration Sub-Study Only 6. Participant should not have received a current season influenza vaccine, have no contraindication to the specific vaccine to be administered in the study, and no prior history of allergy or severe reaction to seasonal influenza vaccines.