When African leaders arrive in Washington this week to meet with President Obama, one of the most politically sensitive issues expected to be discussed is the future of the U.S. commitment to global efforts to deal with HIV/AIDS.

For more than a decade, the United States has taken the lead in this fight, providing significant funding — $52 billion so far — to the cause through a program known as the President’s Emergency Plan for AIDS Relief (PEPFAR). Begun by President George W. Bush in 2003, it is widely considered to be among the most successful foreign policy initiatives in history, credited with saving countless lives and helping to enhance the nation’s image abroad.

The program remains one of the country’s most important foreign aid initiatives under Obama, but its budget has been cut significantly in recent years. Administration officials say it’s time to start shifting some of the responsibility for funding and managing the epidemic to the affected countries. That has been an unwelcome change for many — disrupting care on the ground for some patients and creating worry among HIV/AIDS advocates that some nations don’t have a robust enough medical infrastructure to handle the additional burden.

Congress is still debating the program’s allocation for fiscal 2015, a situation that has created deep concern among some health officials and activists in Africa.

“The funding issue has set off a certain amount of anxiety or existential angst,” said J. Stephen Morrison, director of global health policy research for the Center for Strategic and International Studies. “People are wondering whether this is a slow winding down.”

How familiar are you with Africa’s geography?

Funding for PEPFAR has been shrinking since 2011, but the decline in appropriated money has been offset by a reserve fund that administrators could draw on. Now, that “pipeline” funding has been used up.

Deborah Birx, the administration’s global AIDS coordinator who runs the program, said program administrators are meeting with representatives from countries receiving aid to discuss how they can be more “geographically efficient,” but that the number of countries that could see significant changes “has not been specifically determined.”

“We have to face the reality of our current budget environment,” Birx said. “We have the tools to change the course of the pandemic but we have to focus on using the dollars so that they have the biggest impact in the most geographically relevant way.”

Birx, an Army veteran and scientist who previously led the Centers for Disease Control and Prevention’s efforts on HIV/AIDS, said her team is trying to figure out whether the money is going to the right places, in particular, those with the highest prevalence of HIV.

Birx said she wants to increase programs for pregnant women and their babies, children younger than 5, and girls and young women ages 15 to 19. A recent United Nations report on AIDS found alarmingly high rates in the latter group.

“If there is any message I could carry to the African leaders, it is to continue to work on this and understand how important this is to their future economic development,” she said, adding, “Together in partnership this can be done — but it has to be done in partnership.”

PEPFAR is one part of a two-pronged global strategy the United States is pursuing against AIDS. The country also gives a significant amount to the Global Fund, a multinational effort to fight infectious disease. If the government’s spending on PEPFAR and the Global Fund are combined, the funding has been almost stable — $6.2 billion for 2015 — even as other forms of foreign aid have been cut.

But AIDS activists said that with so many promising treatments being rolled out — including Truvada, a drug taken as a preventive measure by partners of those infected, and microbicides to prevent HIV infection— it’s time to be ramping up funding.

“We are at a critical juncture in terms of the epidemic and new biomedical interventions,” said Serra Sippel, president of the Center for Health and Gender Equity.

Matthew Kavanagh, senior policy analyst for the Health Global Access Project and a fellow at the University of Pennsylvania Center for Public Health Initiatives, agreed. He said that the money translates directly into the number of people treated and that any reduction in funding would result in lives lost.

“That is not going to get us ahead of the wave of new infections,” he said.