Australia's National Notifiable Diseases Surveillance System 1991-2011: expanding, adapting and improving

Area of Science:

• Public Health Surveillance
• Infectious Disease Epidemiology
• Health Information Systems

Background:

• The National Notifiable Diseases Surveillance System (NNDSS) is crucial for monitoring infectious diseases in Australia.
• Evaluating the NNDSS's performance over its initial two decades is essential for identifying areas of improvement.

Purpose of the Study:

• To assess the key attributes of Australia's NNDSS, specifically flexibility, data quality, and timeliness, over its first 21 years (1991-2011).
• To describe changes in the number of notifiable diseases, diagnostic methods, data completeness, and notification delays within the NNDSS.

Main Methods:

• Analysis of notified cases within the NNDSS from 1991 to 2011, stratified by jurisdiction and time sub-period.
• Examination of trends in the number of notifiable diseases, use of Polymerase Chain Reaction (PCR) testing, data completeness for key variables, and notification delays.

Main Results:

• The number of notifiable diseases increased from 37 to 65. The proportion of cases diagnosed by PCR rose significantly from 1% to 49%.
• Data completeness showed improvement, though some fields like Indigenous status (44%) and country of acquisition (24%) remained incomplete. Median notification time decreased from 11 days to 5 days.
• Despite expansion, NNDSS demonstrated improved data completeness and timeliness, likely due to mandatory laboratory reporting and electronic data transfer.

Conclusions:

• Australia's NNDSS has evolved significantly, showing improvements in data quality and timeliness over its first 21 years.
• Further enhancements, particularly a nationally integrated electronic surveillance system with electronic laboratory reporting, are recommended to strengthen infectious disease surveillance.