Review of diphtheria, tetanus and pertussis vaccines in clinical development.

Diphtheria, tetanus and pertussis vaccines have formed the cornerstone of childhood immunization programs for decades. Historically, these have comprised diphtheria and tetanus toxoids combined with inactivated whole-cell pertussis. More recently, advances have been made with the development of purified acellular pertussis vaccines, with improved reactogenicity profiles, and formulation with additional vaccines such as Haemophilus influenzae type b, hepatitis B virus and inactivated poliovirus. Development is currently focused on maximizing the number of vaccines that can be combined in a single formulation and strategies to provide protection against pertussis before the commencement of routine infant immunization.