Data sources
The graphs and tables are sourced from the Notifiable Conditions Information Management System (NCIMS).
General guides
The graphs and tables present the number of notifications for each notifiable disease by either month, quarter or year of disease onset.
Data completeness
The completeness of case ascertainment will vary with the notification requirements of the particular disease, how likely the person with the illness is to present for medical care, and the case definition criteria.
For example, as rabies is universally fatal without treatment, a very high proportion of rabies cases will be notified because a case will almost always be brought to medical attention. The disease is notifiable by medical practitioners, laboratories and hospitals, and there is a robust test method for diagnosis.
On the other hand, only a small proportion of influenza cases will be notified because most sufferers do not seek medical attention, are unlikely to be tested if they do present, and influenza is notifiable only by a single source (laboratories).
Timeliness
Data is current and accurate as at the displayed "Last updated" date. The number of cases reported is, however, subject to change, as cases may be entered at a later date or retracted upon further investigation. The longer the time between the period of interest and the "run-date", the more likely it is that the data are complete and the less likely they are to change.
Duplicate case reports
All databases require a process of systematic audit and duplicate removal. Duplicate removal for NCIMS is continuous.
Case definitions
Please refer to the Australian National Notifiable Diseases Case Definitions.
Onset date
Onset date is defined as the date the patient reported that symptoms first appeared. When that date is not recorded, the onset date is calculated as the earlier of specimen date or date of notification.
Data are presented for NSW residents only. Cases diagnosed in NSW for people who reside elsewhere are not included in the graphs and tables.
Disease specific guides
Influenza
Influenza may be categorised as Influenza - Not-specified, Influenza A, Influenza B, or Influenza A and B. Only Influenza A and Influenza B are reported here. Dual infections with influenza A and B are included in the Influenza Not-specified category.
Chickenpox and Shingles
Emergency Department (ED) visits, exclude planned ED visits, but may include individuals re-presenting to ED for the same condition. Emergency Department diagnoses are entered by hospital clinical staff at the end of the visit. Diagnoses that are available for selection may vary across hospitals, Local Health Districts and Specialty Networks which can lead to variation in coding practice. PHREDSS reporting hospitals include 88 facilities that have participated continuously since 2016 and have recorded reasonably complete diagnosis information over the reporting period. The 88 facilities account for approximately 95% of all NSW ED visits. Fewer hospitals participated prior to 2016, so data for 2011 to 2015 are not included for Chickenpox or Shingles. A full list of participating hospitals is available on request. Data are preliminary and subject to change as updates are received. The last month of data is refreshed only at the end of the month.
Hepatitis B
Hepatitis B includes notifications classified as “Hepatitis B – unspecified” and “Hepatitis B – newly acquired”. Hepatitis B is classified as “unspecified” when the time of infection is unknown or is known to be longer than two years prior to diagnosis. Hepatitis B is classified as “newly acquired” when there is evidence that the infection was acquired within two years of diagnosis, either from serology or previous negative testing.
Hepatitis C
Hepatitis C includes notifications classified as “Hepatitis C – unspecified” and “Hepatitis C – newly acquired”. Hepatitis C is classified as “unspecified” when the time of infection is unknown or is known to be longer than two years prior to diagnosis. Hepatitis C is classified as “newly acquired” when there is clinical and/or laboratory evidence that the infection was acquired within two years of diagnosis.
Syphilis
Syphilis includes notifications classified as “infectious syphilis - less than two years duration” and those classified as “syphilis- greater than two years or unknown duration” and excludes congenital syphilis. Syphilis is classified as “infectious syphilis - less than two years duration” when there is evidence that the infection was acquired within two years of diagnosis. Syphilis is classified as “syphilis- greater than two years or unknown duration” when the time of infection is unknown or is known to be longer than two years prior to diagnosis. Reporting delays for all categories of syphilis may occur due to the time it takes to obtain enhanced surveillance information and classify cases.
