A Study Looking at the Effectiveness and Safety of a COVID-19 Vaccine in South African Adults

Inclusion Criteria:

All subjects:

- Adult male and female aged ≥ 18 to < 65 years at screening for Cohorts 1 and 2 and
Adult male or female aged ≥ 65 to < 85 years at screening for Cohort 1 only.

- Body mass index (BMI) of 17 to 40 kg/m².

- Provides informed consent prior to study participation and is willing to comply with
study procedures, including potential home visits.

- 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 21 days prior
to enrolment in the study, through 6 months after the last vaccination.

HIV-negative subjects only:

- Documentation of HIV-negative test result by a method approved in South Africa.

- Healthy at study screening, as determined by the investigator.

HIV-positive subjects only:

- Documentation of HIV-positive test result by a method approved in South Africa.

- Receiving highly active antiretroviral therapy (HAART) and has been using the same
regimen for at least 8 weeks before screening. Changes in antiretroviral dosage within
8 weeks of entering the study are allowed, as are exchanges in pharmacological
formulations.

- Medically stable at screening, as determined by the investigator, and free of
opportunistic infections in the 1 year prior to first study vaccination.

- Have a HIV-1 viral load < 1000 copies/mL within 45 days of randomization in the study.

Exclusion Criteria:

- Any current acute illness requiring medical or surgical care, or chronic illness
(excluding HIV in HIV-positive subjects) that requires changes in medication in the
past 2 months indicating that chronic illness/disease is not stable.

- Chronic disease, including:

1. Hypertension (elevated blood pressure [BP]) ≥ grade 2 (systolic BP ≥ 160 mmHg;
and/or diastolic BP ≥ 100 mmHg) according to the South African Hypertension
Society's Practice Guidelines. NOTE: Hypertension [elevated BP] ≤ grade 1
(systolic BP ≤ 159 mmHg; diastolic BP ≤ 99 mmHg) according to the South African
Hypertension Society's Practice Guidelines is NOT exclusionary;

2. Congestive heart failure with a history of an acute exacerbation of any severity
in the prior 2 years;

3. Chronic obstructive pulmonary disease (COPD) with a history of an acute
exacerbation of any severity in the past 2 years;

4. Evidence of unstable coronary artery disease in the past 3 months, as determined
by the investigator; NOTE: Stable coronary heart disease is NOT exclusionary.

5. Asthma requiring regular/chronic control medication (eg, short-acting
beta2-agonist [SABA] > 2 days per week; or any chronic use of inhaled
corticosteroids [ICS], long-acting beta2-agonist [LABA], leukotriene receptor
antagonist [LTRA], or oral corticosteroids), and/or worsening of asthma symptoms
in the past 3 months; NOTE: Asthma not requiring regular/chronic control
medication, and not requiring SABA > 2 days per week, and not demonstrating
worsening of symptoms in the past 3 months, will NOT be excluded.

6. Type 1 or 2 diabetes (adult onset) requiring treatment with insulin; NOTE:
Non-insulin dependent type 2 diabetes is NOT exclusionary.

7. Chronic kidney disease/renal insufficiency;

8. Chronic gastrointestinal and hepatic diseases;

9. Chronic neurological diseases (such as multiple sclerosis, dementia, transient
ischemic attacks, Parkinson's disease, degenerative neurological conditions,
neuropathy, or epilepsy), or a history of stroke within 12 months with residual
symptoms, or previous neurological disorder within 12 months with residual
symptoms; NOTE: History of migraine or chronic headaches, or nerve root
compression that have been stable on treatment for the last 4 weeks are NOT
exclusionary.

- Participation in research involving an investigational product (drug/biologic/device)
within 45 days prior to first study vaccination.

- Prior receipt of investigational or approved COVID-19 vaccine at any time.

- History of a diagnosis of suspected or confirmed COVID-19.

- Received influenza (flu) vaccination within 14 days prior to first study vaccination;
or any other vaccine within 4 weeks prior to first study vaccination; or planned
vaccination with 5 weeks after first study vaccination.

- Any autoimmune or immunodeficiency disease/condition (excluding HIV in HIV-positive
patients).

- Chronic (more than 14 days continuous) administration of immunosuppressant, systemic
glucocorticosteroids, or other immune-modifying drugs within 90 days prior to first
study vaccination (excluding HAART in HIV-positive subjects). 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.

- Received immunoglobulin, blood-derived products, or other immunosuppressant drugs
within 90 days prior to first study vaccination (excluding HAART in HIV-positive
subjects).

- Acute respiratory and/or non-respiratory illness consistent with potential COVID-19,
concurrent with or within 14 days prior to first study vaccination, or documented
temperature of > 38°C during this period.

- Known blood clotting disorder.

- Active cancer (malignancy) within 3 years prior to first study vaccination (with the
exception of adequately treated non-melanoma skin cancers, as assessed by the
investigator).

- Any known allergies to products contained in the investigational product, or latex
allergy, or any history of anaphylaxis in relation to any previous vaccination.

- Women who are breastfeeding or who are pregnant at the time of screening, or plan to
become pregnant within the first 6 months of the study.

- History of alcohol abuse or drug addiction within 2 years prior to the first study
vaccination.

- Any condition (other than HIV in HIV-positive subjects) that, in the opinion of the
investigator, would pose a health risk to the subject if they participate in the
study, or could interfere with evaluation of the study vaccine or interpretation of
study results.

- Study team member or first-degree relative of any study member.

Other protocol-defined inclusion/exclusion criteria may apply