With 24,000 participants and a formidable star power that include Bill Clinton, Bill and Melinda Gates, Richard Gere, singer Alicia Keys, actress Olympia Dukakis, and Canadian rockers Our Lady Peace and Barenaked Ladies, many are calling the International AIDS Conference beginning on Sunday in Toronto 'The Super Bowl Of Conferences' or the 'World Cup of Conferences', depending on which part of the world they belong.
Among the scientific community, however, it is the promising new HIV prevention approaches that are creating a bigger buzz than the celebrity endorsement. "New approaches and tools that prevent transmission of HIV such as male circumcision, cervical barriers such as the diaphragm, giving pre-exposure prophylaxis (PrEP) with antiretrovirals, and microbicides are some ways of reducing transmission," says Dr Helene Gayle, president, International AIDS Society and co-chair of the conference. Efficacy trials are underway and appear promising, with most of the results expected in 2007/08.
While scaling up treatment by making it affordable is an obvious priority, prevention remains crucial for the disease that newly infected 4.1 million people and killed almost 3 million people in 2005.
Two factors that are likely to have a direct impact on preventing new infections in India are suppression of herpes and use of vaginal microbicides. Ongoing trails in Africa, Latin America and Uganda are testing the efficacy of the off-patent drug acyclovir to suppress herpes, a sexually transmitted infection that can triple the risk of HIV acquisition. The results are expected in 2007 and 2008.
While microbicides that target HIV or the molecules of the cells it infects are in early stages of research, first generation microbicides that lower HIV transmission are in late-stage trial, with the results expected in 2008.
Studies are ongoing in Kenya and Uganda to confirm the South Africa trial last year that showed that circumcised men had a 60 per cent lowered risk of becoming HIV infected than uncircumscised men. The results are expected next year. Researchers in South Africa and Zimbabwe are also testing the effectiveness of contraceptives that work as cervical barriers such as the diaphragm.
Animal studies indicate that drugs used to treat HIV may also prevent infection in HIV-negative people, and efficacy trials in Botswana, Thailand and Peru are expected to over in 2008.
In the words of Gayle, "HIV is not a simple epidemic to handle: the virus mutates rapidly, treatment is expensive, lack of infrastructure makes delivery difficult and changing behaviour remains a tough endeavour."