David D. Ho (BS ’74, Biology)

2015 Distinguished Alumnus

David D. Ho

(BS ’74, Biology)

Director and Chief Executive Officer, Aaron Diamond AIDS Research Center; Irene Diamond Professor, The Rockefeller University

For his positive impact on human health, elucidating the dynamic nature of HIV replication in infected persons and forming the foundation for combination antiretroviral therapy, which has led to reductions in AIDS-associated mortality.

When looking at the history of HIV and AIDS research, it is impossible not to mention the work of David Ho. A recognized leader at the forefront of the field, Ho has spent nearly his entire professional career devoted to the disease. His breakthrough research in the mid-1990s directly led to a series of groundbreaking treatments. Ho’s discoveries have earned him numerous accolades, including Time magazine’s Man of the Year in 1996 and a Presidential Citizens Medal in 2001.


Born in Taiwan, Ho moved with his family to the United States in 1965, when he was 12. He began attending Caltech in 1971, where he became interested in medicine. “It was clear that biology in the early 1970s was really about to break out,” Ho said. “So I chose to go to medical school. It was a rare option for a Caltech student at the time; there were only a handful of us.”

In many ways, Ho began his medical career at ground zero of the AIDS outbreak. In 1981, he was a young medical resident at Cedars-Sinai Medical Center in West Hollywood when a patient came through the doors exhibiting symptoms of a then-unknown illness.

“He was a mystery to all of us,” Ho said. “The patient had various infections and tumors—suggesting the immune system was impaired—but his medical history offered no reason. We treated him as well as we could, but he soon died. Then, there was another case. Followed by another. And it began showing up in other parts of the country.” Eager to learn more about this mystery illness, Ho joined the infectious-disease group at Harvard Medical School, where he became one of AIDS’ earliest researchers.

Over the next decade, AIDS turned into a global epidemic. The more scientists learned about the virus causing it—now known as HIV—the more questions were raised. Why, for instance, did so many who tested positive for HIV appear asymptomatic for years? A theory formed—and became generally accepted—that the virus incubated in a kind of “dormant phase,” content to quietly ride along inside its host before transitioning to a more aggressive pattern.


  • Massachusetts Institute of Technology, 1970–’71

  • BS, Biology, Caltech, 1974

  • MD, Harvard Medical School, 1978

  • Residency, Internal Medicine,
    Cedars-Sinai Medical Center, UCLA School of Medicine, 1978–82


Current Position


Selected Awards


Video: David Ho's acceptance speech at the 2015 Distinguished Alumni Awards, held during the 78th Annual Seminar Day on Caltech's campus, May 16th. Credit: Caltech Academic Media Technologies

Ho, however, suspected that something else was going on and in the mid-’90s led a now-famous study using patients’ treatment data as well as novel mathematical and computer simulations to model the replication rates and mutations of the virus. 

“At the time, there was not a lot of mathematical study in biological research,” Ho said. “Today it’s an integral part with gene sequencing and big data, but back then math was a separate discipline. I credit my Caltech training for equipping me to step back and look at the problem differently.” 

Ho announced his results in 1996, and they were alarming. Not only was HIV not dormant, it was engaged in a vigorous onslaught of the immune system the entire time—even as the body seemed healthy. Then, at a critical point of immune impairment, other opportunistic diseases simply swept into the body unopposed. 

Even more disturbing, Ho’s models demonstrated that with such a high replication rate, the virus was continually mutating. “That meant no matter what drug you threw at it, the virus would effectively evolve a way around it,” Ho said.

The discovery, however, sparked new ideas. “Now that we knew something about the mutation paths,”  Ho said, “it might be possible to attack on multiple fronts simultaneously to slow it down.” Ho championed a combination antiretroviral therapy, commonly referred to as the AIDS cocktail, consisting of multiple medications acting like a blitzkrieg against the virus. While not a cure, it has durably controlled the virus and dramatically prolonged the lifespan of millions.

Today, Ho is CEO of the Aaron Diamond AIDS Research Center in New York. His research is aimed at measures to prevent infection. He is also an outspoken advocate for extending treatments to third-world nations, particularly those in Africa, the worst affected by AIDS.

“We’ve made some great progress in the last decade,” said Ho. “But with infection rates still so high, we can’t just treat our way out of this disease; we must continue to focus on slowing its spread. There is still so much to do.”


by Ben Tomlin
Photo: Danny Ghitis


Colored scan of a T cell infected by HIV. Ho's novel research revealed HIV's high mutation rate, which made it resistant to normal drug treatment.

Ho treating one of his most famous patients, Magic Johnson. Based on his research, Ho championed a combination antiretroviral therapy, which has dramatically increased the lifespan of millions infected by HIV.

Ho was named  TIme  Man of the Year in 1996.        Images courtesy of David Ho; the Aaron Diamond Research Center

Ho was named TIme Man of the Year in 1996.

Images courtesy of David Ho; the Aaron Diamond Research Center

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