SEATTLE — The $1.3 billion that the United States government has spent since 2005 encouraging Africans to avoid AIDS by practicing abstinence and fidelity did not measurably change sexual behavior and was largely wasted, according to a study presented on the last day of an AIDS conference here.
The study, done by a second-year student at Stanford Medical School for a professor with an expertise in cost-benefit analyses, caused a major stir in the room where it was presented.
The researcher, Nathan Lo, analyzed records showing the age of people having sex for the first time, teenage pregnancy and number of sexual partners in international health surveys that have been paid for by the State Department since the 1970s.
His work was overseen by Dr. Eran Bendavid, an assistant professor of medicine at Stanford, who has done previous analyses of American global anti-AIDS programs for the Institute of Medicine, a branch of the National Academy of Sciences.
Global health specialists came to the microphone to congratulate Mr. Lo. Advocates who had long opposed the American policy that sought to prevent AIDS by promoting abstinence and faithfulness applauded.
“That was fantastic,” said Dr. Gilles van Cutsem, medical coordinator for Doctors Without Borders in South Africa.