Study to Evaluate the Immunogenicity and Safety of GlaxoSmithKline (GSK) Biologicals' Herpes Zoster Vaccine GSK1437173A When Co-administered With GSK Biologicals' Seasonal Influenza Vaccine GSK2321138A in Adults Aged 50 Years and Older

Inclusion Criteria:

- Subjects who, in the opinion of the investigator, can and will comply with the
requirements of the protocol (e.g. completion of the diary cards, return for follow-up
visits).

- A male or female aged 50 years or older, at the time of the first vaccination with the
study vaccine(s).

- Written informed consent obtained from the subject.

- Female subjects of non-childbearing potential may be enrolled in the study.

- Non-childbearing potential is defined as pre-menarche, current tubal ligation,
hysterectomy, ovariectomy or post-menopause.

- Female subjects of childbearing potential may be enrolled in the study, if the
subject:

- has practiced adequate contraception for 30 days prior to vaccination, and

- has a negative pregnancy test on the day of vaccination, and

- has agreed to continue adequate contraception during the entire treatment period
and for 2 months after completion of the vaccination series.

Exclusion Criteria:

- Use of any investigational or non-registered product (drug or vaccine) other than the
study vaccines within 30 days preceding the first dose of study vaccine, or planned
use during the study period.

- Chronic administration (defined as more than 14 consecutive days) of
immunosuppressants or other immune-modifying drugs within six months prior to the
first vaccine dose (for corticosteroids, this will mean prednisone ≥ 20 mg/day, or
equivalent). A prednisone dose of < 20 mg/day is allowed. Inhaled, topical and
intra-articular corticosteroids are allowed.

- Administration or planned administration of a vaccine not foreseen by the study
protocol within the period starting 30 days before the first dose of study vaccine(s)
(HZ/su and/or FLU-D-QIV vaccines) and ending 30 days after the last dose of HZ/su
vaccine.

- Administration of an influenza vaccine during the six months preceding entry into the
study or planned administration up to the last blood sampling with the exception of
the FLU-D-QIV vaccine given during this study.

- Administration of long-acting immune-modifying drugs (e.g. infliximab) within six
months prior to the first vaccine dose or expected administration at any time during
the study period.

- Concurrently participating in another clinical study, at any time during the study
period, in which the subject has been or will be exposed to an investigational or a
non-investigational vaccine/product (pharmaceutical product or device).

- Previous vaccination against VZV or HZ and/or planned administration during the study
of a VZV or HZ vaccine (including an investigational or non-registered vaccine) other
than the study vaccine.

- History of HZ.

- Any confirmed or suspected immunosuppressive or immunodeficient condition resulting
from disease (e.g., malignancy, HIV infection) or immunosuppressive/cytotoxic therapy
(e.g., medications used during cancer chemotherapy, organ transplantation or to treat
autoimmune disorders).

- History of any reaction or hypersensitivity likely to be exacerbated by any component
of the vaccines.

- History of Guillain Barré syndrome.

- Hypersensitivity to latex.

- Acute disease and/or fever at the time of enrolment.

- Fever is defined as temperature ≥ 37.5°C /99.5°F for oral, axillary or tympanic
route, or ≥ 38.0°C /100.4°F on rectal route. The preferred route for recording
temperature in this study will be oral.

- Subjects with a minor illness (such as mild diarrhoea, mild upper respiratory
infection) without fever may, be enrolled at the discretion of the investigator.

- Administration of immunoglobulins and/or any blood products within the 3 months
preceding the first dose of study vaccine or planned administration during the study
period.

- Pregnant or lactating female.

- Female planning to become pregnant or planning to discontinue contraceptive
precautions before 2 months after the last dose of study vaccine.

- Any condition which, in the opinion of the investigator, prevents the subject from
participating in the study.

- Any condition which, in the judgment of the investigator would make intramuscular
injection unsafe.