Inclusion Criteria:

• Subjects who completed participation in primary phase of this study.
• Subjects who the investigator believes can and will comply with the requirements of the protocol should be enrolled in the study.
• Written informed consent obtained from the subject.
• Healthy subjects as established by medical history and clinical examination before entering into the study.
• If the subject is female, she must be of non-childbearing potential or be post-menopausal; if of childbearing potential, she must practice adequate contraception for 30 days prior to vaccination, have a negative pregnancy test and continue such precautions for two months after completion of the vaccination series.

Exclusion Criteria:

• Administration of any licensed vaccines within 4 weeks prior to enrolment in this study.
• Planned administration of a vaccine not foreseen by the study protocol: 4 weeks prior to any visit or within 30 days after vaccination.
• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the first visit or planned use during the study
• Any confirmed or suspected immunosuppressive or immunodeficient condition, or autoimmune diseases such as Guillain Barre Syndrome, based on medical history and physical examination (no laboratory testing required).
• History of hypersensitivity to vaccines.
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.
• History of chronic alcohol consumption and/or drug abuse.
• Acute clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests.
• Serious chronic disease including any medically significant chronic pulmonary, cardiovascular, renal, neurological, psychiatric or metabolic disorder, as determined by medical history and physical examination.
• Acute disease at the time of enrolment.
• Administration of immunoglobulins and/or any blood products within the three months preceding the first visit or planned use during the study.
• Pregnant or lactating women.
• Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine(s) within 30 days prior to the first visit, or planned use during the study period.
• Any condition which, in the opinion of the investigator, prevents the subject from participation in the study.