This study will assess the immunogenicity and reactogenicity of the investigational DTaP-HB-PRP~T combined vaccine when given as a booster dose, concomitantly with OPV, in Filipino children previously primed at 6, 10, and 14 weeks with the investigational DTaP-HB-PRP~T combined vaccine or Tritanrix-Hep B/Hib™ vaccine and having received a first dose of Hep B vaccine (Recomvax B™) at birth in a previous study, AL201 (NCT00348881).