The President's Emergency Plan for AIDS Relief, or PEPFAR, is an international initiative introduced by U S President George W. Bush in 2003 to provide treatment for people with AIDS. Now some researchers have looked at its results.

In January 2003, President Bush proposed the fund to get more antiretroviral drugs to people with HIV and AIDS in poor countries. Over five years, the program spent close to $20 billion. It's one of the most expensive foreign aid initiatives ever undertaken. But some people question whether foreign aid to Africa even works, says Eran Bendavid, a researcher at Stanford University.

"And there is a lot of back-and-forth with people who say that, you know, a lot of the foreign aid that we have given Africa, it has gone to waste and has done nothing," he says.

So Bendavid examined statistics from target countries about the number of AIDS deaths and the prevalence of HIV - that is, the number of people who live with the disease. He says he found two results.

"There is a reduction in the number of deaths in the countries where PEPFAR was operating of about 10 percent. And what we mean by that is that during those years when PEPFAR was operating, the number of deaths in those countries was about 10 percent lower than what we would have expected, absent PEPFAR."

The second finding, Bendavid says, is that the prevalence - the rate of people living with the disease - has remained largely unchanged over time.

"The prevalence number is a little bit confusing, and we don't have a final answer about why that is the case. But one possible explanation is that by preventing deaths, PEPFAR is actually enlarging the number of people who are living with HIV, and, as a result, the prevalence is sort of staying relatively high."

Bendavid says both researchers and government officials need to look hard at this prevalence trend.

"Prevalence is really how difficult the epidemic is going to be to reverse. If in a country where 20 to 30 percent of the population is infected, well? that's a very heavy burden. It's going to be a difficult task. And how to reverse that is a major, major task."

Prevalence is a number that's related to how well disease transmission is being prevented. Bendavid says perhaps one place to look is at how well PEPFAR does at prevention programs that will reduce the number of infections.

His research is published in the Annals of Internal Medicine.