A national surveillance system for newly acquired HIV infection in Australia

Objectives. The purpose of this study was to describe the establishment of a national surveillance system for newly acquired human immunodeficiency virus (HIV) infection and present the first 3 years' results. Methods. All new cases of diagnosed HIV infection were reported to the national HIV surveillance center through state and territory health authorities. Information sought on each case included evidence of whether the infection had been newly acquired, defined by the diagnosis of HIV seroconversion illness or by the report of a negative or indeterminate HIV antibody test result occurring within the 12 months prior to diagnosis of infection. Results. Of 3602 reported cases of HIV infection in adults and adolescents newly diagnosed in Australia between 1991 and 1993, 11.4% were identified as newly acquired. The majority (85%) of cases of newly diagnosed HIV infection occurred among men who reported homosexual contact, and 15% of these cases were identified as newly acquired. Average age at diagnosis was 31 years for cases of newly acquired infection and 34 years for other cases. Conclusions. Surveillance for newly acquired HIV infection has been established at a national level in Australia and provides valuable information for planning primary HIV prevention programs.