A Phase 2, Multicenter, Open-label Study to Assess the Immunogenicity of an Investigational Hib Vaccine (NU300)in Toddlers

Inclusion Criteria: 1. Written informed consent obtained from the parent or guardian of the subject 2. Male or female subjects 12-15 months of age at the time of booster vaccination, who had previously received complete primary vaccination series with a licensed Hib product and Prevnar 13® in accordance with the FDA approved labels. 3. Subjects for whom the investigator believes that the parent/guardian can and will comply with the requirements of the protocol 4. Subjects free of obvious health problems as established by medical history and clinical examination before entering the study Exclusion Criteria: 1. Previous booster vaccination against Hib and/or Prevnar 13® 2. Any confirmed or suspected Haemophilus influenzae or pneumococcal illness. 3. Administration of a vaccine not foreseen by the study protocol during the period starting from 30 days before and ending 28 days after administration of study vaccines (before the blood draw at Visit 2). 4. Chronic administration of immunosuppressants or other immune-modifying drugs within 30 days prior to dosing in the study. 5. Any confirmed or suspected immunosuppressive or immunodeficient condition based on medical history and/or clinical examination. 6. Early pre-term birth (delivery before 32 weeks). 7. Major congenital defects or serious chronic diseases, or serious conditions including history of seizures, apnea, etc. 8. Concurrent participation in another clinical study at any time during the study period or within the previous 6 months in which the subject has been or will be exposed to an investigational or non-investigational product (pharmaceutical product, formula, or device) 9. Presence of a moderate or severe illness with or without fever at the time of vaccination (fever is defined as a temperature of ≥ 38.0C \[100.4F\]). 10. Known history of thrombocytopenia or any coagulation disorder. 11. Known hypersensitivity to any of the components of the vaccines. 12. Known hypersensitivity to latex. 13. The subject is unable to provide an adequate blood draw for immunogenicity assays, and safety panels at Visit 1