Cautious Optimism

Other experts who study Ebola urged caution with reports of Dr. Brantly’s dramatic recovery on the drug.

Thomas Geisbert, MD, professor of infectious disease at The University of Texas Galveston Medical Branch, has been studying the Ebola virus since 1988.

He says news accounts that Brantley’s rash disappeared in just an hour after receiving a dose of the drug don’t make sense to him.

“When I look at a monkey that has a rash from hemorrhagic fever, small blood vessels have already ruptured,” Geisbert says. “It takes some time for the skin to recover.”

He says other news accounts have stated that Brantly also received blood from a patient who recovered from the infection. That blood might have had protective factors in it.

He says that makes it hard to sort out what might have helped.

“If we can prove that whatever the treatment was worked, that’s fantastic,” he says. “That’s exciting. But I’m cautiously optimistic, because with this particular outbreak, almost 40 percent of patients survive without treatment. So we want to make sure that it wasn’t somebody that was going to survive anyway."

But Saphire says the accounts of Brantly’s speedy turnaround seem plausible to her.

“It hasn’t been used in humans before, so we didn’t know what would happen,” Saphire says. “But antibodies in general can be very effective.”

“I was worried, because in the studies in monkeys, you can save all of them if you treat within 24 hours. If you wait several days for disease to develop, you save half,” she says. She adds that researchers had their fingers crossed that it wouldn’t be too late for Brantly and Writebol, who had been infected for days before they received their doses.

But she says that in the animal experiments, the monkeys were given very high doses of the virus, which may have made it harder to treat.

She says she doesn’t know how that would compare to health care workers infected in a clinic setting.

Saphire says she expects the first human trials of ZMapp to begin in 2015.