New technologies for HIV prevention could have a huge impact on the epidemic, possibly averting millions of new infections in the coming years, the International Aids Conference in Toronto heard on Tuesday.
Gita Ramjee, of the HIV prevention research unit in South Africa, said there is a range of new and promising prevention technologies in advanced clinical trials.
Trials investigating the effectiveness of microbicides, male circumcision, cervical barriers, pre-exposure prophylaxis (Prep) and herpes suppressive therapy were underway and results were expected in the next two years.
”The good news is that 2007/8 is going to be a very good year for prevention,” said Ramjee.
She said she wanted to extend the prevention alphabet of ABC (Abstain, Be faithful, Condomise), to include another C for Circumcision, D for Diaphragm, E for Exposure prophylaxis (pre- and post-), F for Female controlled microbicides, G for Genital-tract infection control, H for HSV-2 suppressive treatment and I for Immunity.
In 2005, 4,1-million people were infected with HIV; these rising numbers have highlighted the urgent need to scale-up prevention as a method of controlling the epidemic.
A 60% effective microbicide could avert 2,5-million new HIV infections in middle- to low-income countries, while widespread implementation of male circumcision in sub-Saharan Africa could avert two million new infections over the next 10 years, said Ramjee.
Inexpensive cervical barriers could reduce the impact of HIV among women, while Prep could see HIV reduced in high-risk individuals. Herpes suppressive therapy could lower acquisition and transmission of the virus.
”We know how HIV is transmitted, and how transmission can be prevented. Now we need to implement programmes [for prevention],” said Cristina Pimenta, executive director of the Brazilian Interdisciplinary Aids Association.
Addressing a plenary session on the third day of the conference, Pimenta said 1,3-million people in low- and middle-income countries were receiving antiretroviral treatment (ARV).
”We have seen it is possible to mobilise resources globally, but we seem to be moving backwards with prevention,” she said.
Microbicides have been seen as an answer to HIV prevention that puts the power in the hands of women, giving them the right ”to inform or not to inform” men of their use.
Currently in the form of a gel, microbicides could be applied in the vagina to prevent HIV infection, by acting as a physical barrier between HIV and its target cells.
Early research was under way into rectal microbicides, and vaginal rings that would release the microbicide over 30 days.
”We would like [microbicides] with high anti-HIV activity and low toxicity; we want to give the option to have a baby without infection,” she said.
Many products being tested are in the early concept stage, with about 30 to 40 candidates in pre-clinical development. Five microbicides are currently in large scale efficacy trials.
The first results would be released by the end of 2007.
Microbicide trials face several challenges, such as the high rate of pregnancy among the women participating, which resulted in them being taken off the product.
Ramjee said this had a ”huge impact on the statistical power of the trial to show efficacy”.
There were currently three clinical trials for the cervical barrier, another women-initiated method which has proven to be safe, effective and affordable.
There has been a lot of interest in studies that show circumcised men have a reduced risk of HIV. Epidemiological evidence from studies showed circumcised men had a lower HIV prevalence and a South African study showed men in randomised control trials had a lowered risk of about 60%.
However, this had to be confirmed with further trials.
Pimenta noted the importance of looking at social vulnerabilities when it came to prevention. These vulnerabilities, such as poor social and economic conditions and lack of power, increased an individual or collective susceptibility.
She said it was no longer possible to talk about prevention and care without taking these vulnerabilities into consideration.
Pimenta said programmatic priorities should deal with the social and economic contexts of the population. Understanding existing combinations of stigmas is important to ”diminish and eliminate” its effects. — Sapa