A major trial of an HIV prevention drug is being conducted in New South Wales.
The trial aims to virtually eliminate HIV transmission by 2020.
But, the treatment being tested - which is recommended by the World Health Organisation - has not yet been approved by Australia's drug regulator.
And, as Rachael Hocking reports, doctors in the HIV sector are calling for a rapid roll out of the drug.
Some experts say this trial will be a game-changer.
HIV negative people, who are deemed at high risk of being infected, will receive antiretroviral drugs, known as PreP, to stop them contracting HIV.
The drug is already being trialled in several Australian states, but this will be the largest trial to date.
It will involve 3700 high-risk, mostly gay and bisexual men.
They will be enrolled through New South Wales public sexual health clinics and selected GP practices from March next year.
Professor Andrew Grulich from the Kirby Institute at the University of New South Wales says the trials so far have shown positive outcomes.
"We know PreP works now. We've had several years with demonstration projects, with small-scale projects to see whether it does work in the real world. And the answer is: incontrovertibly "yes" now."
Professor Grulich says this large-scale trial will hopefully see a rapid reduction in the transmission of HIV -- up to a 50 per cent decline in the state of NSW.
He says the next step is for the drug to be made available nationwide.
"Currently the drug is not covered by Pharmaceutical Benefits system and that's what needs to happen to make it affordable. The drug is currently with the regulator, the Therapeutic Goods Administration and will then need to be submitted for funding. That process is likely to take one or two years from now, this study is about making sure we get access today."
The drug known as Truvada is not yet approved by the Therapeutic Goods Administration, nor is it listed on the Pharmaceutical Benefits Scheme.
The NSW Minister for Health, Jillian Skinner, says governments are tackling the problem effectively.
"As part of the World Aids Conference in Melbourne I was very thrilled to have all of the states, territories and the Commonwealth government sign up to our HIV strategy and that included commitment by the Commonwealth government to removing barriers to early treatment."
Experts warn that the drug is not intended to replace condoms.
They say the use of condoms has been declining, and that PreP should not encourage complacency.
Daniel McPhail is taking part in a Victorian trial for the drug, and says it is something gay men have to think about a lot.
"That anxiety that gay men wake up with the next morning - whether or not it's something that happens for a split second, or whether or not it's something that you really do regret and they need to go to a hospital. That's an anxiety that's very unique to the gay community. And something like PreP, that prevents HIV transmission, it eliminates that anxiety and it's no longer an issue for them."
Meanwhile, the Victorian government has announced it will develop guidelines for doctors to prescribe PreP.
