Follow-up Study on the Antibody Response to Hepatitis B, Acellular Pertussis Toxin and Inactivated Poliovirus Antigens 1 Month After the 4th Hexavac® Vaccination in Healthy Children, Who Participated in NeisVac-C Study 216

Inclusion Criteria: Study subjects who completed study 216 will be eligible for participation in this study if: they received all 3 vaccinations with Hexavac during study 216 and the 4th Hexavac vaccination outside the study the subject's parent(s)/legal guardian(s) understands the study and has provided written informed consent for his/her child's study participation; a blood draw was performed after the 3rd vaccination during study 216. Exclusion Criteria: Study subjects will be excluded from participation in this study if: they have received any vaccination containing hepatitis B, poliovirus or acellular pertussis toxin antigens other than Hexavac they have received a blood transfusion or immunoglobulins during the period from 28 days prior to the 4th Hexavac vaccination until study entry they have received another vaccine during the period from 28 days prior to the 4th Hexavac vaccination until study entry they are concurrently participating in or have participated in a clinical trial with an investigational medicinal product since the completion of study 216 they suffer from a disease (e.g. autoimmune disease) or were undergoing a form of treatment that may be expected to influence immunological functions since the completion of study 216 they have received systemic corticosteroids during the period from 28 days prior to the 4th Hexavac vaccination until study entry.