- Systematic surveillance of newly diagnosed cases of HCV infection is recognised as a key component of the Australian response to the hepatitis C epidemic.
- The results of hepatitis C antibody testing have been used to analyse hepatitis C prevalence and incidence, including the results of HCV testing carried out at sentinel sites and the annual Needle and Syringe Program (NSP) Survey.
BackgroundThe broad aims of hepatitis C surveillance are to:
- monitor trends and patterns in HCV transmission and the outcomes of HCV infection;
- guide and evaluate interventions; and
- provide early warning of changing patterns of HCV transmission and disease.
The ability to track the incidence of hepatitis C through routine surveillance is limited by the lack of symptoms and of laboratory markers associated with acute infection.
5.1 Compilation and analysis of Hepatitis C diagnosesHCV infection has been a notifiable condition (doctor and/or laboratory) in most Australian State and Territory Health jurisdictions since 1990, and all States and Territories since 1995. Cases of newly diagnosed hepatitis C infection are reported via State and Territory Health Departments to the National Notifiable Diseases Surveillance System. The extent to which there have been duplicate hepatitis C notifications is uncertain.
In each State/Territory, new hepatitis C diagnoses have been notified with case-identifying data, so that within each State/Territory duplicate notifications are likely to be limited. However, new hepatitis C diagnoses are forwarded by State/Territory Health Departments to the National Notifiable Diseases Surveillance System, maintained by the Australian Government Department of Health and Ageing, in anonymous aggregate format. This means that it is not possible to assess duplicate notifications between State/Territories.
While enhanced surveillance mechanisms to improve ascertainment of newly acquired hepatitis C cases were introduced in most State and Territory health jurisdictions, the vast majority of hepatitis C notifications have been prevalent hepatitis C diagnoses rather than newly acquired hepatitis C cases.
Newly acquired cases of HCV infection often cannot be separated from other reported cases because of limited capacity to verify previous negative results; and the relatively limited implementation of enhanced surveillance of notifications by States and Territories due to resource implications.
While HCV infection is a notifiable disease, it is unclear how prevalent hepatitis C is in Aboriginal and Torres Strait Islander people, due to the continued failure to identify Indigenous status. In order to ensure accurate data, it is critical that all people diagnosed with hepatitis C are requested to confirm their status.
5.2 Sentinel site surveillance for hepatitis CHepatitis C testing is routinely carried out at a number of sentinel sites such as sexual health clinics, Aboriginal Community Controlled Health Services, prisons, primary healthcare sites, drug user organisations and blood transfusion services. The numbers of people tested, and the proportion with diagnosed HCV infection are reported on a regular basis from these sites and provide estimates of hepatitis C prevalence and incidence in various population groups.
5.3 Special annual surveyThe Australian Needle and Syringe Program Survey is co-ordinated by NCHECR and has been carried out over one week each year since 1995. During the designated survey week, NSP staff ask all clients who attend to complete a brief, self-administered questionnaire and provide a finger prick blood sample. The subjects are assured that the specimens are tested under code, so the results cannot be linked back to individuals.
This survey provides limited information on comparisons of hepatitis C infections between jurisdictions and over time.