Landmark AIDS Model Gets an Upgrade
The year was 1991. Steven Seitz, a professor of political science in LAS, was seated at a computer in front of Ugandan President Yoweri Museveni and 10 of his top advisors. They were watching the screen fill with colored graphs depicting the prevalence of AIDS in Uganda. The program beeped as the lines climbed higher, driving home the severity of the situation: nearly 14 percent of Uganda's 25 million citizens were infected with the AIDS virus. In the capital city of Kampala, more than 20 percent of adults were infected.
What Seitz remembers most about the day was the Ugandans' response when the lines dropped after he factored in the effects of changes in behavior, such as the use of condoms on infection rates. The next day, President Museveni reversed his earlier stand against the use of condoms. Uganda became the first African country to promote safe sex. A decade later, it is the only African nation to have reversed its AIDS infection rates. Its prevalence has dropped from 14 percent to 5 percent.
Seitz cannot claim credit for the improvement. But his model's role in this success is one of the reasons that iwgAIDS (interagency working group AIDS) is used worldwide and was recently revised.
"Previously, it was thought that sexual behavior choices were so idiosyncratic that they could not be reduced to principles of modeling," says Seitz. "But we found that such choices could be modeled." The model simulates how more than 100 variables—describing a population's demographic characteristics, sexual behavior, and prevalence of AIDS viral infection—influence the spread of the disease.
The revised model—upgraded at the request of the United States Agency for International Development, which supported the model's initial development—takes advantage of recent advances in computing technology. The result, Seitz hopes, will be additional answers to questions about AIDS as well as other diseases.
By Holly Korab