Corynebacterium diphtheriae is endemic in the Northern Territory (NT), and is regularly cultured from wound and nasopharyngeal swabs, particularly in Aboriginal people. Universal vaccination with diphtheria toxoid and maintenance of adult boosters with adult diphtheria tetanus {ADT) vaccine at least once every 10 years is the only effective control measure. Although vaccination against diphtheria does not prevent or reduce carriage of C. diphtheriae, it helps boost antibody levels against the diphtheria toxin and hence protects against
development of the toxigenic disease. The presence of C. diphtheriae does not necessarily mean that the person has systemic disease.