Persistency Study After Hib-CRM (Cross-Reacting Material)197 or Hib-TT (Tetanus Toxoid) Vaccines in Chinese Children

Inclusion Criteria: 1. Children previously enrolled in V37\_07E1 study and who received the appropriate vaccination. 2. Children whose parent(s) or legal guardian(s) had given written consent after the nature of the study was explained according to local regulatory requirements. Exclusion Criteria: 1. Any confirmed or suspected current immunosuppressive or immunodeficient condition since the end of V37\_07E1 study, based on medical history and physical examination (no laboratory testing required). 2. Treatment with corticosteroids or other immunosuppressive/immunostimulant drugs as defined below: i) chronic use of oral and parenteral immunosuppressants (\>= 15 days of use) or other immune-modifying drugs within 60 days prior to the blood sampling (short term usage of topical, inhaled and/or intranasal corticosteroids were allowed) ii) receipt of immunostimulants within 60 days prior to Visit 1 3. Administration of immunoglobulins and/or any blood products up to 3 months before enrollment. 4. Use of any investigational or non-registered product (drug or vaccine) within 30 days preceding the blood sampling. 5. Any condition, which, in the opinion of the investigator, might be a contraindication to the execution of the blood draw.