Has pertussis increased in NSW over the past decade? An evaluation using hospitalisation and mortality data versus notifications 1988-2002.

Pertussis, or whooping cough, notifications, and deaths declined dramatically after the introduction of mass vaccination in the 1950s, to the extent that many states stopped collecting notifications. However, since 1990, notification rates have increased noticeably from the record low levels seen in the 1970s and 1980s in all Australian states and territories, including NSW. A number of factors, other than a true increase in the underlying incidence of pertussis, may account for this. These factors include: improved surveillance, the introduction of direct notification of cases by laboratories, and the introduction of additional means of laboratory diagnosis such as serology and nucleic acid testing. In contrast to notifications, criteria for coding hospital separations or deaths due to pertussis are less likely to have been influenced by these changes, thus providing a data source that is more consistent over time to evaluate for HAS PERTUSSIS INCREASED IN NSW OVER THE PAST DECADE? AN EVALUATION USING HOSPITALISATION AND MORTALITY DATA VERSUS NOTIFICATIONS 1988–2002