The trial is a parallel group, multi-centre, randomized, double blind, non-inferiority trial investigating the immunogenicity and safety of two DTaP-IPV combination vaccines:

A)The investigational vaccine: DTaP-IPV containing IPV produced in a vero-cell line (DTaP-IPVvero) B)The reference vaccine: DTaP-IPV containing IPV produced in monkey kidney cells (DTaP-IPVmkc) The DTaP-IPV vaccines are administered to healthy infants at 2, 3½, 5, and 16 months of age concomitantly with Act-HIB vaccine administered as a separate injection in the opposite thigh.

Three blood samples are collected at 6, 16 and 17 months of age. Sera are analyzed for antibodies against diphtheria, tetanus, pertussis, polio and prp.

Inclusion Criteria:

• The parents were informed about the trial and have signed the consent form
• The subject is healthy
• The subject has an age of 28 to 49 days at hepatitis B vaccination
• The subject had a birth weight of ≥2500 g
• The subject has received a hepatitis B vaccination at birth
• The parents grant access to the subject's medical records
• The parents are likely to comply with instructions

Exclusion Criteria:

• The subject suffers from a severe chronic disease
• The subject has already been immunized with one or more doses of diphtheria, tetanus, pertussis, poliomyelitis, or Hib vaccines
• The subject has a known allergy to one of the vaccine components or to any of the constituents of the vaccines, including Act-HIB® and hepatitis B vaccines
• The subject has a history of diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B, or Hib infections
• The subject has a known congenital or acquired immunodeficiency
• The subject is in treatment with or has been in treatment with a product which is likely to modify the immune response (i.e. immunoglobulin, systemic corticosteroids, blood products, other vaccines)
• The subject is participating in another clinical trial