HIV diagnoses declined in Australia during the 1990s only to increase again through the 2000s, with Victoria having the second highest number of HIV diagnoses and the most substantial increase in the country.
Diagnoses in Victoria doubled from 130 in 1999 to 259 in 2006 and has stabilised at approximately 250 cases annually since then. Men who have sex with men (MSM) continue to be the group at greatest risk.
The Centre for Population Health carries out surveillance for HIV infection and AIDS in Victoria. Surveillance activities allow us to monitor disease trends and inform public health policy and action to improve prevention of HIV infection and facilitate early diagnosis and treatment to reduce morbidity and mortality associated with AIDS.
HIV/AIDS passive surveillance involves the collection of enhanced information alongside demographic data at the time of diagnosis.
That is the diagnosing doctor provides information on the patient’s most likely route of exposure; most likely place of infection; clinical characteristics such as symptoms; reason for test; and the date, location and result of previous HIV tests.
This additional information allows surveillance to identify groups who are at risk and help with our understanding of behaviours and trends associated with risk which is key to informing public health action.
In addition, all HIV anti-body test data is collated from the laboratories as part of HIV enhanced passive surveillance to detect changes in trends of HIV testing in Victoria.
In the past decade passive surveillance has reported the increasing number of HIV cases newly diagnosed in Victoria as well as the decline in AIDS related deaths since the introduction of Highly Active Anti Retroviral Treatment (HAART).
The overall increase in new HIV cases is driven mainly by MSM however there are early indicators of changing trends in the epidemic.
Among MSM a significant decrease in age at diagnosis was detected in 2008; for the first time a significant decline in the median age of MSM diagnosed with HIV in Victoria was observed.
There was an increased proportion of MSM aged less than 35 years being diagnosed with HIV since the introduction of HAART suggesting that younger MSM in Victoria could be at increased risk of HIV infection with this trend continuing in 2009.
It has also been observed that HIV cases reporting heterosexual sex as their mode of transmission test less frequently than MSM and present for testing at later stages of their disease suggesting a potential pool of undiagnosed cases who are unaware of their HIV risk.
These findings highlight the importance of ongoing monitoring HIV/AIDS in Victoria and ensuring prevention and early detection messages are designed to include the groups who may not recognise their HIV risk.