Susan Allen: Confronting HIV in Africa

In the early years of the HIV epidemic, researchers and health workers assumed that the partners of HIV-positive individuals would also be infected. But in 1988, Susan Allen, then a researcher at UCSF, made a startling discovery. While tracking HIV in pregnant Rwandan women, Allen found that 14% of her 1,500 research subjects did not share the same HIV status as their partners (1). To Allen, this discordance made these women and their partners an ideal co-hort both to understand the factors that determine virus transmission and to identify strategies to prevent it. Allen soon started a program in which both partners received counseling about prevention strategies and were routinely tested. Her approach had a huge payoff: HIV incidence among coun-seled couples is 50–70% lower than among non-counseled couples (2). Allen's progress came to a brutal stop during the Rwandan geno-cide. Hundreds of her subjects and half of her program's staff were killed. But rather than return to the United States, she used research funds formerly bound for Rwanda to start a similar program in Zambia. Today, Allen's program—known as the Rwanda Zambia HIV Research Group—includes the largest and longest-standing cohort of HIV-discordant couples in the world. It has helped to identify strategies that reduce HIV transmission and to uncover the effects of the host's genotype and immune response on the evolution of the virus (3, 4). You were poised to start a surgical career after fi nishing medical school. How did you end up as a HIV researcher in Africa instead? When AIDS started to hit the radar in 1984, I was doing my residency in pathology in San Francisco, which turned out to be one of the epicenters of the epidemic. One of the guest speakers at the hospital where I was doing autopsies on young, AIDS-ravaged gay men was a Belgian internist who had treated African AIDS patients. The internist described otherwise healthy people dying of diseases that shouldn't have been lethal— something that we were also seeing among the AIDS victims in San Francisco. The patients were diff erent, but the mortality was the same. This doctor had access to blood samples from AIDS patients in Kigali, the capital of Rwanda. But these were the times before the virus had been isolated, before there were blood tests to detect it. So the doctor and his colleagues in Rwanda had a hard time figuring out if this …