The Secretariat of the Joint United Nations Programme on HIV/AIDS (UNAIDS) has lost valuable ground by ignoring for years the contribution of long-term concurrent relationships to Africa's AIDS epidemic, claims says Helen Epstein, an independent consultant on public health in developing countries, ahead of World AIDS Day on British Medical Journal (www.bmj.com) today.

UNAIDS may be "contributing to the mystification of AIDS in Africa by promoting a needlessly overcomplicated view of the epidemic", says Epstein.  She argues that long term, overlapping, or "concurrent" partnerships provide at least a partial explanation for the staggeringly high infection rates in the general population in some African countries, and calls for UNAIDS to reassess its handling of scientific data. 

Epstein speculates that UNAIDS' tendency to emphasize only typical high risk behaviors such as casual sex and prostitution may have hindered prevention, promoted denial and stigma, and contributed to HIV associated domestic violence by implying that people with HIV are necessarily promiscuous.

In fact, African people do not seem to have more sexual partners than people in other countries, but they are more likely to have two or three long term "concurrent" partnerships at a time, and this creates a "virtual superhighway" for HIV. 

Condom use is rare on this "superhighway" because long term relationships, even concurrent ones, are seldom perceived as risky. This may explain why reductions in sexual partners have been a crucial factor wherever infection rates have fallen in Africa, she says. For example, in Uganda, a 60% fall in casual partnerships coincided with a 70% fall in HIV prevalence during the 1990s. In addition, declines in HIV prevalence in the US gay community and Thailand were also accompanied by rapid declines in multiple partnerships.

According to Epstein, for years UNAIDS overlooked independent reports about the importance of partner reduction, and until 2006, did not mention long-term concurrency in its reports on sexual behavior.

Concurrency does not imply a simple solution to the AIDS crisis in Africa, she says, but education about the "superhighway" could help motivate behavioural change, especially partner reduction, and should be integrated into all AIDS education programmes in Africa.

Epstein concludes by calling on the new UNAIDS director and its governing board to re-evaluate the agency's political and scientific roles, and suggests that scientific issues be addressed through a more open process of research and peer review, rather than by one, largely unregulated UN agency.

In a second feature, Bob Roehr examines how institutionalised homophobia and the criminalisation of homosexual activity are aiding the spread of HIV and hindering efforts to provide treatment and prevention among men who have sex with men. According to Dr Peter Piot, director of UNAIDS, homophobia is one of the top five obstacles to stopping the epidemic.