A concerning rise in the number of Australian HIV cases in the past seven years is likely to be mainly due to risky sexual behaviour in men having sex with men, and some clear geographic differences in trends are starting to emerge, according to research published online for the Medical Journal of Australia.
Professor John Kaldor, Deputy Director and Professor of Epidemiology at the National Centre in HIV Epidemiology and Clinical Research at the University of New South Wales, and his colleagues in State and Territory health departments and the Burnet Institute in Melbourne, studied changes in the number of HIV cases diagnosed from 1993 to 2006.
Prof Kaldor says HIV exposure through male-to-male sex accounted for 70 per cent of all cases, followed by heterosexual contact at 18 per cent.
"The annual number of new HIV diagnoses declined by 32 per cent between 1993 and 1999, but then increased by 31 per cent between 2000 and 2006," says Prof Kaldor.
"In New South Wales, long the State with the highest rate of HIV, the trend had been stable over the past five years, but in other parts of the country the trend was upwards with Victoria now roughly equal to New South Wales in per capita diagnoses."
In more than half of heterosexually acquired cases, the person was born in or had a partner from a country with a high prevalence of HIV.
Exposure to HIV from injecting drug use was infrequent.
Prof Kaldor says an increase in risky sexual behaviour due to changing perceptions of the seriousness of HIV may have contributed to the high rates of exposure in men having male-to-male sex.
"While Australia remains a low-prevalence country for HIV, evidence that the recent increase in diagnoses in some states is linked to changes in risk behaviour raises questions about the effectiveness of current prevention strategies," says Prof Kaldor.
The publication of the study coincides with the International AIDS Conference to be held in Sydney on 22-25 July, the largest scientific gathering on HIV to be held in Australia.
The full article can be viewed online at www.mja.com.au
The Medical Journal of Australia is a publication of the Australian Medical Association.