A new drug that gives almost complete protection against the virus was to be administered across Africa this year. Now, much of the funding for that effort is gone.

This was supposed to be a breakthrough year in the 44-year-long struggle against H.I.V. A breakthrough preventive drug, lenacapavir, a twice-yearly injection that offers total protection from H.I.V., was to be rapidly rolled out across eastern and southern Africa. The main target: young women. About 300,000 of them were newly infected with the virus last year — half of all new infections worldwide…

There is more potential than ever before to end the H.I.V. epidemic, scientists and public health experts say. But now, H.I.V. programs across Africa are scrambling to procure drugs that the United States once supplied, replace lost nurses and lab technicians, and restart shuttered programs to prevent new infections.

I’ve been traveling through Sierra Leone and Liberia to gauge the impact of Trump’s closing of U.S.A.I.D., to see how bad things have gotten. Here is what I see: children are dying because medicines have been abruptly cut off, and risks of Ebola, tuberculosis and other diseases reaching America are increasing — while medicines sit uselessly in warehouses.

Join me in the village of Kayata, Liberia, where in April a pregnant mother of two, Yamah Freeman, 21, went into labor. Freeman, a lively woman known for her friendliness to all, soon hemorrhaged and began bleeding heavily, so villagers frantically called the county hospital to summon an ambulance.