Journal of Clinical Virology 22 (2001) 297 – 303 Time trends in HIV incidence among homosexually active men seen at sexual health clinics in Australia, 1993–1999 Ann McDonald a, *, Basil Donovan b , Catherine O’Connor c , Don Packham d , John Patten e , John Chuah f , Russell Waddell g , Christopher K. Fairley h , John Kaldor a a National Centre in HIV Epidemiology and Clinical Research, 376 Victoria Street, Darlinghurst, NSW 2010, Australia b Sydney Sexual Health Centre, Sydney, NSW, Australia c Liingstone Road Sexual Health Centre, Marrickille, NSW, Australia d Parramatta Sexual Health Clinic, Westmead, NSW, Australia e Brisbane Sexual Health Clinic, Brisbane, Qld, Australia f Gold Coast Sexual Health Clinic, Miami, Qld, Australia g Sexually Transmitted Diseases Serices, Adelaide, SA, Australia h Melbourne Sexual Health Centre, Carlton, Vic., Australia Abstract Background: increases in sexual risk behaviour have recently been reported among homosexually active men in Australia and in other industrialised countries, potentially facilitating an increase in HIV incidence. Objectie: to monitor HIV incidence among homosexually active men seen through a network of sexual health clinics in Australia. Study design: selected metropolitan public sexual health clinics provided counts of the number of people seen at the clinics during a calendar year, the number voluntarily tested for HIV antibody and the number newly diagnosed with HIV infection, broken down by sex, age group, HIV exposure category and HIV antibody testing history. HIV incidence was estimated among homosexually active men with a history of a negative test in the 12 months prior to last being seen in a calendar year. Results: of 23 924 men seen at the clinics in 1993–1999 with a reported history of male homosexual contact, 7440 (31.1%) had a negative test in the 12 months prior to last being seen in a calendar year. The percentage of men with a recent negative test declined significantly over time, from more than 33% in 1994–1996 to 29% in 1999 (P =0.003), and with increasing age, from 34.3% among men aged 25–29 years to 27.4% among men aged 40 years or older (P 0.0005). A total of 5346 (71.9%) men were retested for HIV antibody within 12 months of the last negative test. The percentage of men retested declined significantly over time, from 77.8% in 1994 to 67.2% in 1999 (P =0.021) but did not change by age group (P =0.132). Overall, 56 men were newly diagnosed with HIV infection. Estimated HIV incidence was 2.1% in 1993 – 1999; incidence did not change significantly by year (P =0.498) or age group (P =0.757). Conclusion: HIV incidence has remained stable among homosexually active men seen through a network of sexual health clinics in Australia. © 2001 Elsevier Science B.V. All rights reserved. Keywords: HIV incidence; Homosexually active men; Sexual health clinics; Australia www.elsevier.com/locate/jcv * Corresponding author. Tel.: +61-2-9332-4648; fax: +61-2-9332-1837. E-mail address: amcdonald@nchecr.unsw.edu.au (A. McDonald). 1386-6532/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S1386-6532(01)00202-5