Stark warning about HIV in Australia

Mar 5 2008

A new study has a stark warning about HIV numbers in Australia. According to recent research, if current trends continue, parts of Australia could be facing a surge of HIV infection rates in the next 7 years.

The study by researchers at the University of New South Wales (UNSW) predicts a rise of 75 percent in HIV infection rates in Victoria and a 20 percent rise in Queensland.

The researchers, based at the National Centre in HIV Epidemiology and Clinical Research (NCHECR) used a mathematical model to show how HIV infections will behave from data gathered from the beginning of 1999.

The model also predicts the number of new cases in New South Wales will decrease.

The report focuses on men who have sex with men because it is in this population that the increase in HIV has primarily been seen.

Lead researcher Dr. David Wilson from NCHECR says though the raw numbers are less than they were at the peak of the HIV/AIDS crisis in 1988, the trend is worrying.

Dr. Wilson who is a HIV mathematical modelling expert says most new infections are happening in Victoria, Queensland and New South Wales.

Dr. Wilson says the suspicion was that reduced levels of condom were behind increasing trends and differences between States, but they found that condom usage could not explain the full extent of the increase.

Dr. Wilson says even when the direct effects of a drop in condom use, changes in numbers of sexual partners, disclosure of HIV status to partners, HIV testing rates and rates of early antiretroviral treatment were combined, the increases could not be reproduced.

The report found that the trends in HIV notifications could only be reproduced by a factor that increased the susceptibility of HIV transmission in male homosexual intercourse such as another sexually transmitted infections (STIs).

STIs are known to increase the susceptibility of HIV transmission in heterosexuals and notifications for chlamydia, gonorrhea and syphilis have increased substantially in Australia in recent years; herpes too is also common in the Australian gay population.

When these factors were included in the computer model for male homosexual HIV transmission, the observed increases in HIV were able to be reproduced.

Dr. Wilson says if an HIV positive person has an STI, it is two to five times more likely that they will transmit the virus and there is also a greater likelihood that a person will become HIV positive if they have an STI.

The decrease condom use will lead to more STIs and may be indirectly responsible for explaining the majority of the increases in HIV infections says Dr. Wilson.

He says the most effective intervention for interrupting HIV transmission in Australia is too promote condom use along with the targeting of other STIs.

The report also reveals another important point...it seems that almost one-in-five transmissions amongst gay men are from men who have been recently infected, which is when the levels of virus are highest in the body.

What is more, almost one in every three new infections were estimated to be transmitted by the approximately 13 per cent of men who have undiagnosed HIV infection.

The research was conducted in close consultation with a Steering Committee, consisting of national HIV experts of sexual behaviour, clinical practice, epidemiology, infectious diseases, and community and government based organisations.