Surveillance for newly acquired hepatitis C in Australia.

Background: The purpose of the present paper was to determine recent patterns of hepatitis C virus (HCV) transmission in Australia through a national system of enhanced surveillance of newly acquired hepatitis C.

Methods: Demographic, clinical, and risk behavior information on newly acquired hepatitis C cases from 1997 to 2000 was collected. Newly acquired hepatitis C included cases of HCV antibody sero-conversion within a 12 month period and acute clinical hepatitis C cases.

Results: Nine hundred and twelve cases of newly acquired hepatitis C were identified, representing 2.8% of all HCV notifications for this period. The majority of cases (72%) were diagnosed in people aged between 20 and 39 years. Injecting drug use was reported in the vast majority of cases (93%), with sexual transmission (2%) and tattooing (2%) reported in small numbers. HCV antibody sero-conversion was the mode of diagnosis in most cases (78%).

Conclusions: Injecting drug use is the main route of HCV transmission in Australia. As only a small proportion of HCV infections are detected as newly acquired, enhanced surveillance procedures, including increased regular HCV testing of at-risk populations are required to more effectively monitor recent patterns of transmission.