A top U.S. infectious diseases doctor says excitement over ebola drug treatments is premature.

Hope of a possible cure surged around the world last week after two American volunteers who caught the virus while treating patients in Liberia received an experimental ebola therapy, ZMapp, USAToday reports.

Medications for ebola are promising and will hopefully help in future outbreaks, but they can’t be made in enough quantities to benefit current patients, said Anthony Fauci, longtime director of the U.S. National Institute of Allergy and Infectious Disease.

The drug has been tested only in animals but never before on humans. Both patients were transported to the U.S. and are recovering, though it is unclear whether the drug made the difference, according to USAToday.

The two recovering missionaries received the kind of fast and attentive care that Fauci says he advocates for everyone — but that is extremely difficult to provide in West Africa.

The most powerful tool against the outbreak is basic medical care, Fauci said — replacement fluids and blood.

Researchers are scrambling to develop treatments, diagnostics and vaccines to fight ebola.

When asked why the two Americans needed to be evacuated when they were receiving care in a specialized facility in Liberia, Fauci said the demand on West African hospitals was overwhelming. “Sure, there’s infrastructure for taking care of two people, but what happens when there’s 150 people in there?”

ZMapp “will take two to three months to just get a real, very modest number of treatment courses,” in which each patient would require three doses of the drug, he said. “You’ll never have enough to give it to everybody — you won’t even come minutely close to that.”

Drugs under development will not be a big part of the solution, Fauci said. They are too early in development for enough doses to be manufactured, even if they are shown to be safe.

Instead, focus should be on setting up medical infrastructure in the affected countries to provide sick people with basic medical support such as replacement fluids and blood. That will have a much bigger effect on health than a few batches of experimental medications, he said.

“That’s the way you help people,” he said. “The idea of ‘What are we going to do with these four treatment courses we have?’ is almost irrelevant of the big picture of the lives that you can save mainly by getting people into proper care.”

No drugs or vaccines are approved for preventing or treating ebola. Supportive therapy such as replacing fluids, particularly when done soon after infection, can significantly improve survival chances, USAToday reports.

The death rate is about 55 percent in the current outbreak, with 1,711 cases and 932 deaths in Guinea, Sierra Leone, Liberia and Nigeria, according to the World Health Organization.