The changing epidemiology of pertussis in the Hunter New England area and potential implications for the immunisation schedule.

A complete understanding of the epidemiology of Bordetella pertussis is complicated by imperfect diagnostic methods and incomplete recognition, testing and notification of the disease. It is generally agreed that notification rates represent an under-reporting of actual incidence. However, Australia has improved surveillance for pertussis since the early 1990s and currently has the highest reported pertussis incidence rates of any country in the world. Between 4,000 and 10,000 cases have been reported each year since 1993, an incidence of between 22 and 58 per 100,000 population.