DECEMBER 30, 1996/JANUARY 6, 1997 VOL. 148 NO. 29

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There are other problems. Even if the treatment works, it isn't practical. HIV-positive patients would have to start taking the drugs immediately after infection, before they realize they're sick. And even if the drug cocktails can be made to work in the later stages of infection, they are far too expensive to do much good for the 20 million people in the developing world who are infected with HIV. In the long run, scientists believe, only an AIDS vaccine will stop the global epidemic.

Still, it's easy to understand the tentative sense of hope and excitement that has spread across the AIDS community in the months since the Vancouver conference. Ho's speech, for all its caveats, provided the first concrete evidence that HIV is not insurmountable. After 15 years of horror, denial and disappointment, the pendulum may at long last be swinging against AIDS.

A TEAM EFFORT

David Ho would be the first to say that he cannot take all the credit. It was an immunologist from Los Angeles named Michael Gottlieb who in 1981 reported the first cases of what was then called gay pneumonia. It was the U.S. Centers for Disease Control that alerted doctors to the gathering epidemic and established that the infection was transmitted through blood transfusions, tainted needles and unprotected sex. It was Dr. Luc Montagnier's laboratory at the Pasteur Institute in Paris that first isolated the killer virus in 1983. It was Dr. Robert Gallo and his colleagues at the National Cancer Institute in Bethesda, Maryland, who made it grow in the lab, which allowed for the development of an antibody test. It was the National Institutes of Health that funded the basic research on HIV and AIDS. It was the big drug companies like Burroughs Wellcome and Merck that brought a growing list of anti-HIV drugs to market.

But Ho, working alone or in concert with others, fundamentally changed the way scientists looked at the AIDS virus. His breakthrough work in virology, beginning in the mid-1980s, revealed how HIV mounts its attack. His tenacious pursuit of the virus in the first weeks of infection helped show what the body does right in controlling HIV. His pioneering experiments with protease inhibitors helped clarify how the virus ultimately overwhelms the immune system. His work and his insights set the stage for an enormously productive shift in the treatment of AIDS away from the later stages of illness to the critical early days of infection.

Once, not so long ago, researchers believed that nothing much happened after HIV gained entry into the body. The virus simply hunkered down inside a few of the immune system's T cells--the linchpins of the body's defensive forces--for anywhere from three to 10 years. Then something, no one knew what, spurred the microbial invader to awaken. In this picture, the AIDS virus spent most of its life hibernating before starting its final, deadly assault.

In the past two years, Ho and his colleagues have demonstrated that this picture of the virus is wrong. There is no initial dormant phase of infection. Ho showed that the body and the virus are, in fact, locked in a pitched battle from the very beginning. At first many AIDS researchers found this hard to accept; it challenged some of their most cherished assumptions. If Ho was right, doctors would have to radically alter the way they treated AIDS.

It wasn't the first time that Ho had overturned conventional wisdom. During the past 15 years, he has demonstrated an uncanny ability to ask questions that seem obvious only in retrospect and to probe key issues others have overlooked. It's a trait that does not endear him to some of his rivals. A few have accused Ho of being a publicity seeker who is giving AIDS patients false hope. Upon examination, however, most of the accusations appear to spring from professional jealousy. "David is the type of individual whom I feel particularly good about when he achieves success," says Dr. George Shaw, one of Ho's strongest competitors, who runs a state-of-the-art AIDS research laboratory at the University of Alabama in Birmingham. "He is a stellar scientist."

Ho has an extraordinary knack for being in the right place at the right time. Two years after he received his M.D. from Harvard Medical School, Ho witnessed the birth of the AIDS epidemic. He remembers how baffling it seemed.

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