When the first dose of Ambirix was administered concomitantly with a booster dose of a combined diphtheria, tetanus, acellular pertussis, inactivated poliomyelitis and Haemophilus influenzae type b vaccine (DTPa-IPV/ Hib) or with the first dose of a combined Measles-Mumps-Rubella vaccine in the second year of life, immune responses to all antigens were satisfactory.