Immunogenicity of a Single Dose of GSK Biologicals' Boostrix™ in Infants Prior to Primary Pertussis Vaccination, When Administered to Pregnant Women as Per Routine Practice in Bogota, Colombia

Inclusion Criteria: Criteria applicable at screening (before the birth of the infant): * Male or female infants whose mothers have received Boostrix during their current pregnancy, as per routine practice. * Infant whose parents, in the opinion of the investigator, can and will comply with the requirements of the protocol. * Written informed consent obtained from both parents of the infant. Criteria applicable at enrolment (after the birth of the infant): * Confirmation of written informed consent obtained from both parents of the infant at the time of screening. * Infant whose parents, in the opinion of the investigator, can and will comply with the requirements of the protocol. Exclusion Criteria: Criteria applicable at screening (before the birth of the infant): * Infants whose parents are below the legal consenting age of the country. * Infant's whose mother has multiple pregnancies. * Infant's whose mother has any confirmed or suspected immunosuppressive or immunodeficient condition (including positive infection with human immunodeficiency virus \[HIV\]), based on medical history, physical examination or positive test result. * Infant's whose mother is concurrently participating in another clinical study, at any time during the study period, in which the infant's mother has been or will be exposed to an investigational or a non-investigational vaccine/product. Criteria applicable at enrolment (after the birth of the infant): * Child in care. * In case of multiple births. * Infants with any confirmed or suspected immunosuppressive or immunodeficient condition , based on medical history, physical examination or positive test result. * Infants who are concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational vaccine/product.