The purpose of this study is to develop immunological assays on blood samples.

This is a clinical study in which there is no vaccine administered. It is designed for research purposes such as developing immunological assays.

Inclusion Criteria:

• Subjects who the investigator believes that they can and will comply with the requirements of the protocol (e.g. return for follow-up visits).

• A male or female between, and including, 18 and 50 years of age at study start.

• A subject having received a Yellow Fever (YF) vaccine on the day of study entry.

• Written informed consent obtained from the subject.

• Healthy subjects as established by medical history and clinical examination performed on the day of YF vaccination.

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

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

  • has practiced adequate contraception for 30 days prior to study start, and
  • has agreed to continue adequate contraception during the entire study period.

Exclusion Criteria:

• Use of any investigational or non-registered product (drug or vaccine) within 30 days preceding study start, or planned use during the study period.
• Concurrently participating in another clinical study, within 3 months preceding study start and at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational product (pharmaceutical product or device).
• Clinically significant anaemia or any known condition as per medical history that would preclude the drawing of blood as described in the protocol.
• Known previous infection with YF virus.
• Previous vaccination against YF more than approximately 5 hours before the blood sampling at Visit 1.
• Administration of immunoglobulins and/or any blood products within the 3 months preceding the study start or planned administration during the study period.
• Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs (including chloroquine) within six months prior to the study start. For corticosteroids, this will mean prednisone ≥ 10mg/day, or equivalent. Inhaled and topical steroids are allowed.
• Receipt of live attenuated vaccines other than the YF vaccine during the period beginning 30 days preceding the blood sampling at Visit 1 or planned use during the study up to the blood sampling at Visit 2.
• Receipt of inactivated influenza vaccines (seasonal or pandemic) during the period beginning 21 days preceding the blood sampling at Visit 1 or planned use during the study up to the blood sampling at Visit 2.
• History of malignancy (unless there has been surgical excision followed by a sufficient observation period, of at least 5 years, to give a reasonable assurance of sustained cure and which, in the estimate of the investigator, is not likely to recur during the study period).
• Any confirmed or suspected immunosuppressive or immunodeficient condition (including HIV, hepatitis B and hepatitis C), based on medical history and physical examination (no laboratory testing required).
• Family history of congenital or hereditary immunodeficiency.
• Major congenital defects or serious chronic illness.
• Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination and medical history.
• Acute disease and/or fever at the time of enrolment.
• Known pregnant or lactating female, as per medical records.
• Female planning to become pregnant or planning to discontinue contraceptive precautions.
• History of chronic alcohol consumption and/or drug abuse.
• Any condition that may preclude the compliance to the study protocol.