Immunogenicity and Safety Study of SK SARS-CoV-2 Recombinant Nanoparticle Vaccine (GBP510) Adjuvanted With AS03 (COVID-19)

Inclusion Criteria:

- Participant must be 18 years of age and older, at the time of signing the informed
consent;

- Participants who are healthy or medically stable as determined by medical evaluation
including medical history, physical examination, clinical laboratory tests, and
medical judgement of the investigator;

- Participants who are able to attend all scheduled visits and comply with all study
procedures;

- Female participants of childbearing potential must agree to be heterosexually
inactive, or agree to consistently use at least one acceptable method of contraception
from at least 4 weeks prior to the 1st study vaccination to 12 weeks after the last
study vaccination;

- Female participants with a negative urine or serum pregnancy test at screening;

- Capable of giving signed informed consent which includes compliance with the
requirements and restrictions listed in the informed consent form (ICF) and in
protocol;

- Participants who have received 2 doses of GBP510 25μg adjuvanted with AS03 or
ChAdOx1-S and have blood samples until Visit 7 in Stage 1

- Participants who received a primary series of GBP510 or ChAdOx1-S at least 12 weeks
prior to booster vaccination in Stage 2

- Participants who are able to attend all additionally scheduled visits and comply with
all study procedures.

- Female participants of childbearing potential must agree to be heterosexually
inactive, or agree to consistently use at least one acceptable method of contraception
from at least 4 weeks prior to the booster dose (3rd study vaccination) to 12 weeks
after the booster dose

- Female participants with a negative urine or serum pregnancy test prior to the booster
dose (the third dose of study vaccine)

- Capable of giving an informed consent for Stage 2 study in compliance with the
requirements and restrictions listed in the informed consent form (ICF) for Stage 2
and in this protocol.

Exclusion Criteria:

- Any clinically significant respiratory symptoms (e.g., cough, sore throat), febrile
illness (tympanic temperature >38°C), or acute illness within 72 hours prior to the
1st study vaccination. A prospective participant should not be included until 72 hours
after the condition has resolved;

- (Only for Cohort 1) Prior SARS-CoV-2 infection or vaccination confirmed by a positive
result of qualitative test for SARS-CoV-2 antibody using a rapid antibody kit at
screening;

- History of virologically-confirmed SARS or MERS disease, or SARS / MERS vaccination;

- History of congenital, hereditary, acquired immunodeficiency, or autoimmune disease;

- History of bleeding disorder or thrombocytopenia which is contraindicating
intramuscular vaccination;

- History of hypersensitivity and severe allergic reaction (e.g., anaphylaxis,
Guillain-Barre syndrome) to any vaccines or components of the study vaccine;

- History of malignancy within 1 year prior to the 1st study vaccination (with the
exception of malignancy with minimal risk of recurrence at the discretion of the
investigator);

- Significant unstable chronic or acute illness that, in the opinion of the
investigator, might pose a health risk to the participant if enrolled, or could
interfere with the protocol-specified activities, or interpretation of study results;

- Any other conditions which, in the opinion of the investigator, might interfere with
the evaluation of the study objectives (e.g., alcohol or drug abuse, neurologic or
psychiatric conditions);

- Female participants who are pregnant or breastfeeding;

- Receipt of any vaccine within 4 weeks prior to the 1st study vaccination or planned
receipt of any vaccine from enrollment through 28 days after the last study
vaccination (Visit 7), except for influenza vaccination, which may be received at
least 2 weeks prior to the 1st study vaccination. This exception includes monovalent
pandemic influenza vaccines and multivalent influenza vaccines;

- Receipt of immunoglobulins and/or any blood or blood products within 12 weeks prior to
the 1st study vaccination;

- Receipt of any medications or vaccinations intended to prevent COVID-19;

- Chronic use (more than 2 consecutive weeks) of immunosuppressive therapy, such as
anticancer chemotherapy or radiation therapy; or long-term systemic corticosteroid
therapy (≥10mg prednisone/day or equivalent for more than 2 consecutive weeks) within
12 weeks prior to the 1st vaccination. The use of topical and nasal glucocorticoids
will be permitted;

- Participation in another clinical study involving study intervention within 4 weeks
prior to the 1st study vaccination, or concurrent, planned participation in another
clinical study with study intervention during the study period.

- Participants who are subjected to any global or local restrictions in place for use of
ChAdOx1-S (e.g. age, gender, or other specific population groups)

- Investigators, or study staff who are directly involved in the conduct of this study
or supervised by the investigator, and their respective family members.

- Any clinically significant respiratory symptoms (e.g., cough, sore throat), febrile
illness (tympanic temperature >38°C), or acute illness within 72 hours prior to the
booster dose (3rd study vaccination). A prospective participant should not be included
until 72 hours after the condition has resolved.

- History of confirmed COVID-19, SARS or MERS disease confirmed by serological,
virological assay, or rapid antigen kit

- Receipt of any medications or vaccinations intended to prevent COVID-19 except for
GBP510 or ChAdOx1-S.

- Receipt of any vaccine within 4 weeks prior to the booster vaccination or planned
receipt of any vaccine from enrollment through 28 days after the booster vaccination
(Visit 4B), except for influenza vaccination, which may be received at least 2 weeks
prior to the booster vaccination. This exception includes monovalent pandemic
influenza vaccines and multivalent influenza vaccines

- Receipt of immunoglobulins and/or any blood or blood products within 12 weeks prior to
the booster vaccination

- Chronic use (more than 2 consecutive weeks) of immunosuppressive therapy, such as
anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid
therapy (≥10mg prednisone/day or equivalent for more than 2 consecutive weeks) within
12 weeks prior to the booster vaccination. The use of topical and nasal
glucocorticoids will be permitted.