A Study Looking at the Effectiveness, Immune Response, and Safety of a COVID-19 Vaccine in Adults in the United Kingdom

Inclusion Criteria:

- Able and willing to comply with all study requirements.

- Willing to allow investigators to discuss medical history with their General
Practitioner and access all relevant medical records.

- Willing and able to give informed consent.

- Women of child-bearing potential must agree not to have sexual intercourse with men,
or must consistently use an agreed method of contraception, from at least 28 days
prior to enrolment in the study, through 3 months after the last vaccination.

- Room air oxygen saturation > 95% at Screening/Day 0.

- Seasonal Flu Vaccine Co-Administration Sub-Study only: Participant should not have
received a current season flu vaccine, should have no reason why the specific
sub-study flu vaccine cannot be administered, and should not have any prior history of
allergy or severe reaction to seasonal flu vaccines.

Exclusion Criteria:

- Participation in other COVID-19 vaccine or preventative drug trials for the duration
of the study.

- Future participation in any blood tests for the duration of the study where
participants are informed of their levels of COVID-19 antibodies or antigens.

- Participation in any trial involving an investigational drug, biologic or device
within 45 days prior to the first study vaccination.

- History of laboratory-confirmed COVID-19 infection any time prior to first study
vaccination.

- Receipt of any immunoglobulins and/or any blood products within 3 months prior to
planned administration of study vaccine.

- Any confirmed or suspected immunosuppressive or immunodeficient state. Chronic
administration (defined as more than 14 continuous days) of immunosuppressant
medication within the past 3 months, except topical steroids or short-term oral
steroids (course lasting ≤ 14 days). Note: An immunosuppressant dose of glucocorticoid
is defined as a systemic dose ≥ 10 mg of prednisone per day or equivalent. The use of
topical, inhaled, and nasal glucocorticoids will be permitted if other chronic disease
conditions do not exclude a participant from the study.

- History of allergic disease or reactions likely to be made worse by any component of
the study vaccines.

- History of anaphylaxis to any prior vaccine.

- Pregnancy, breast-feeding or willingness/intention to become pregnant within 3 months
following the last study vaccination.

- Current diagnosis of or treatment for cancer (except basal cell carcinoma of the skin
and cervical carcinoma in situ.

- Bleeding disorder, or prior history of significant bleeding or bruising following
intramuscular injections or venepuncture (e.g. to draw blood for tests).

- Continuous use of anticoagulants or anti-platelet agents. Note: The preventative use
of ≤ 325 mg of aspirin per day is permitted.

- Suspected or known current alcohol or drug dependency.

- Study team member or first-degree relative of any study team member (inclusive of
sponsor, contract research organization (CRO), and site personnel involved in the
study).

- Participants having any current workup of undiagnosed illness within 8 weeks prior to
start of study which could lead to new condition or diagnosis.

- Received any live vaccine within 4 weeks or any vaccine (excluding flu) within 2 weeks
prior to first study vaccination; or any licensed flu vaccine within 1 week prior to
first study vaccination or plans to receive any vaccine from these time periods until
28 days after the second study vaccination.

- Have clinically significant chronic cardiovascular, endocrine (hormones),
gastrointestinal, hepatic (including hepatitis B and C), renal (kidney), neurological,
respiratory, psychiatric or other medical disorders not excluded by other exclusion
criteria, that are assessed by the investigator as being clinically unstable within
the prior 4 weeks as evidenced by: a) Hospitalisation for the condition, including day
surgical interventions; b) New significant organ function deterioration; or c) Needing
addition of new treatments or major dose adjustments of current treatments (mild or
moderate well-controlled comorbidities are allowed).

- History of chronic neurological disorders that have required prior specialist
physician review for diagnosis and management (such as multiple sclerosis, dementia,
transient ischemic attacks, Parkinson's disease, degenerative neurological conditions,
and neuropathy) or a history of stroke or previous neurological disorder within 12
months with residual symptoms. Participants with a history of migraine or chronic
headaches or nerve root compression that have been stable on treatment for the last 4
weeks are not excluded.

- Any autoimmune disease/condition (iatrogenic or congenital).

- Any other significant disease, disorder or finding that, in the opinion of the
investigator, may significantly increase the risk to the volunteer because of
participation in the study, affect the ability of the volunteer to participate in the
study, or impair interpretation of the study data.

- Participant requires the use of continuous oxygen therapy or any oxygen therapy while
awake or is anticipated to require daytime oxygen therapy during the course of the
study.

Other protocol-defined inclusion/exclusion criteria may apply.