Nature and extent of the burden and risks associated with participation, benefit and group relatedness: During the study, 9 blood samples (each 20 or 50 mL) will be taken. Total time investment for the subjects will be 160 min. Occasionally, a heamatoma or bruise can occur during venipuncture. After the vaccination a heamatoma or a sore arm can occur. These side effects should disappear within 4-5 days. Other common side effects related to the vaccination are headache, loss of appetite, and fatigue, which usually will disappear within 24 hours.