Professor Sharon Lewin co-authored the latest review of the global HIV epidemic, published in The Lancet.
Professor Lewin, who's the co-chair of the 20th International AIDS Conference next month in Melbourne, says one of the most important advances has been anti-HIV drugs, which dramatically reduces a person's infectiousness, hence leading to fewer transmissions.
Presenter: Sen Lam
Speaker: Professor Sharon Lewin, Director of the Department of Infectious Diseases at the Alfred Hospital and Monash University
LEWIN: Anti-HIV drugs basically stop the virus from replicating in the body, so when the person goes on treatment the levels of virus decrease dramatically, and their immune system recovers, and that's why they no longer get sick. And in fact people that take anti-HIV drugs now have a normal life expectancy if they start the drugs at the right time.
At the same time, the drugs don't only just help the person taking them, the drugs dramatically reduce the amount of virus in the blood, and therefore dramatically reduce the person's infectiousness.
So the chance of that person transmitting HIV reduces by 96 per cent. Therefore, the drugs have an effect not only on the individual, but on larger communities. The more people on treatment, the less transmission of virus we see.
LAM: The report also points to the fact that new HIV infections overall decreased from three-point-three million in 2002, to just over two-million ten years later. Is that largely due to better drugs as you've described, or perhaps a greater awareness of behavioural change or a little of both?
LEWIN: There are a number of factors that have contributed to the global decline in new infections, and interestingly we're not seeing it everywhere, we're seeing very significant declines particularly in countries in sub-Saharan Africa, where over 25 countries have reported a 50 per cent decrease in new infections.
One of the reasons for that is a combination of awareness and behavioural preventions, but probably the biggest factor that has driven a reduction in new infections is the increasing access to anti-HIV drugs. There are now close to ten million people taking anti-HIV drugs in lower middle income countries in 2012, and that's probably one of the biggest drivers in reductions in new infections.
LAM: And the new anti-HIV drugs aside, one of the bright spots is that some people have good anti-body responses to HIV, the so-called broadly neutralising anti-bodies. What's that about?
LEWIN: Yeah that's been a very interesting discovery, which is going to I think have a big effect on vaccine research.
So to get rid of a virus you need to make an immune response to the virus, and the best immune response you can make is to make an antibody and an antibody that recognises many different viruses.
And over the last few years and large collaborative groups of researchers have identified a number of individuals who make these super-duper antibodies that recognise a large number of viruses, not just their own virus.
And if we could engineer that sort of super-duper antibody, to be a vaccine, that could be very, very effective. And that's exactly what's happening at the moment, those antibodies have been very well characterised, and we now have some very elegant ways to make those antibodies in a test tube. And that's given people hope, finding a vaccine has been incredibly tough for HIV, we still don't have a vaccine, an effective vaccine 25 years down the track, but this might be a new and exciting avenue to develop and an effective vaccine.
LAM: So is that a kind of holy grail now, to somehow bottle these neutralising antibodies?
LEWIN: Yeah if we could make those antibodies in a test tube system, make large numbers of them, yes, we could have a big impact on an effective vaccine. We're not close yet to trialling those antibodies, but we've got some very nice new ways to make them in a test tube model.
LAM: You've said that a cure for HIV is now considered a major scientific priority. How would you rate international collaboration? For example cooperation in searching for a solution?
LEWIN: We have excellent treatments that effectively control the virus and allow normal life expectancy, but people need to take those treatments lifelong. So there's a big interest in finding a way that we could safely stop treatments and the virus stays under control, or what one might think about as a 'cure'.
And there's a lot of international interest in developing a cure, and a lot of international collaboration, largely through initiatives through funding bodies, such as the US government, who are encouraging collaborative consortia of researchers to try and tackle this very big problem. We're seeing these large consortiums in the US, in the UK, in Canada and even in Australia now of networks of researchers trying to tackle this very significant problem.