A Study to Evaluate the Safety and Immunogenicity of GlaxoSmithKline Biologicals' Influenza Vaccine GSK3206641A Administered in Adults 18 to 64 Years of Age and 65 Years of Age and Older

Inclusion Criteria

• Healthy participants as established by medical history and clinical examination before entering into the study.
• A male or female ≥ 18 years of age at the time of first vaccination.
• Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g. completion of the diary cards and COVID-19 assessment card, return for follow-up visits, or return the diary cards and COVID-19 assessment card in a timely manner using the pre stamped envelope received at the site).
• Written or witnessed/thumb printed informed consent obtained from the participant prior to performance of any study specific procedure.
• Female participants of non-childbearing potential may be enrolled in the study. Non childbearing potential is defined as pre-menarche, current bilateral tubal ligation or occlusion hysterectomy, bilateral ovariectomy or post-menopause.
• Female participants of childbearing potential may be enrolled in the study, if the participant:
• has practiced adequate contraception for 1 month 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

• Current diagnosis or history of autoimmune disorder(s).
• History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine.
• Hypersensitivity to latex.
• Acute or chronic clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality that appears uncontrolled, as determined by history or physical examination.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).
• Recurrent history or uncontrolled neurological disorders or seizures.
• History of Guillain-Barré syndrome.
• Diagnosed with narcolepsy; or history of narcolepsy in a participant's parent, sibling or child.
• Diagnosed with cancer, or treatment for cancer within 3 years.
• Persons with a history of cancer who are disease-free without treatment for 3 years or more are eligible.
• Persons with a history of histologically-confirmed basal cell carcinoma of the skin successfully treated with local excision only are accepted and are eligible, but other histologic types of skin cancer are exclusionary.
• Women who are disease-free 3 years or more after treatment for breast cancer and receiving long-term prophylaxis (for example, with tamoxifen) are eligible.
• Documented human immunodeficiency virus-positive participant.
• Any clinically significant* hematological laboratory abnormality.

*The investigator should use his/her clinical judgement to decide which abnormalities are clinically significant.

• Bedridden participants.
• Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study.
• Use of any investigational or non-registered product (drug, vaccine or medical device) other than the study vaccine/product during the period beginning 30 days before the first dose of study vaccine/product (Day -29 to Day 1), or planned use during the study period.
• Administration of long-acting immune-modifying drugs at any time during the study period (e.g. infliximab).
• Administration of immunoglobulins and/or any blood products or plasma derivatives during the period starting 3 months before the first dose of study vaccine/product or planned administration during the study period.
• Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs during the period starting 3 months prior to the first vaccine/product dose. For corticosteroids, this will mean prednisone equivalent ≥ 20 mg/day. Inhaled and topical steroids are allowed.
• Concurrently participating in another