World AIDS Day - South Africa on the frontline

01 December 2010 | Story by Newsroom

World AIDS DaySouth Africa continues to be at the epicentre of the fight against HIV, as illustrated by the contributions by the country's research community to three major advancements in 2010, developments that will change the way in which new HIV infections are prevented in the future.

For example, a recent study showed that pre-exposure prophylaxis (a daily dose of an oral antiretroviral) was effective at reducing the risk of HIV acquisition among men who have sex with men, cutting back on infections by as much as 44%. The study involved work by the UCT-based Desmond Tutu HIV Centre, which provided one of the 11 international trial sites across six countries.

"I think this is a very significant study in that what we have here is the first proof of concept that taking an antiretroviral prophylactically, in other words taking it before exposure to HIV, would actually prevent HIV infection," said UCT's Associate Professor Linda-Gail Bekker, deputy director of the Desmond Tutu HIV Centre.v

Bekker was also part of a consortium, IAVI Protocol G, which discovered a range of antibodies that could block more than 90% of HI viruses tested. It is hoped that understanding the structure of these antibodies, and the region of the virus that these antibodies target, will help the development of more effective vaccines.

Additional promising results in HIV prevention research came out of a study by the Centre for the AIDS Programme of Research in South Africa (CAPRISA), which found that a vaginal gel containing the antiretroviral (ARV) drug tenofovir was 39% effective in reducing a woman's HIV risk. Importantly the protection was improved when the microbicide was used consistently. The microbicide gel also halved the incidence of genital herpes infections.

Professor Carolyn Williamson, Dr Jo-Ann Passmore and Dr Wendy Burgers of UCT's Division of Medical Virology and the Institute for Infectious Diseases and Molecular Medicine are among those who are working on the CAPRISA study to understand why women get infected despite using this intervention, with the hope of improving its effectiveness.

The media statement released by the National Institute of Allergy and Infectious Disease (NIAID), part of the National Institutes of Health (NIH) in the US, marking World AIDS Day 2010, highlighted all three prevention studies as milestones in HIV/AIDS research across the world.

Williamson and her sibling, Professor Anna-Lise Williamson, appreciate the value of these findings. But for them a vaccine - which will prompt the immune system to produce the necessary antibodies to the HI virus - remains the holy grail of AIDS prevention.

In 2009, a candidate vaccine developed by them and others at UCT went into clinical testing (the SAAVI 102/HVTN 073 trials) at two sites in South Africa, following trials in the US. Two further trials of the UCT-designed vaccine have now been planned based on some valuable lessons learned from the breakthrough Phase III trial in Thailand that showed - albeit modest - effectiveness, reducing infections by about 31.2%.

The first trial of the UCT-designed vaccine will be an extension of the original trial, with a protein-based vaccine boost added; while a second trial will look at various combinations of prime (the main vaccine) and boosts.

"Historically, vaccines have shown to be the only interventions to eliminate or control viral epidemics," says Carolyn Williamson.

There have been developments on the socio-economic front as well. As indicated in an article, titled Special Report on the state of HIV/AIDS in South Africa, published in Global Health Magazine in August this year, and which counted the Desmond Tutu HIV Centre's Bekker and Professor Robin Wood, and Professor Nicoli Nattrass of UCT's AIDS and Society Research Unit, among its panel of expert authors. That paper lauded the improved rollout of antiretroviral treatments and services, and government's progressive policies and financial injection.

On the other hand, prevention interventions remain weak. "Even under the most optimistic of projections, about five million more South Africans will become HIV infected over the next two decades - roughly the number infected today," wrote the authors.

What's needed, concluded the panel of experts, is a focus on fundamentals and leadership.

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