Sources: Health improving for 2 Americans with Ebola

CHARLOTTE, N.C. — The Samaritan's Purse doctor who is battling the Ebola virus is doing OK as he is being treated at Emory University Hospital in Atlanta.

"Doctor Kent Brantly is doing very well and hopes to be released sometime in the near future," evangelist Franklin Graham said on Twitter Thursday. "Kent and his wife appreciate your prayers."

SPECIAL SECTION: Ebola virus

Meanwhile the son of Charlotte missionary Nancy Writebol, said Friday that his mother is getting stronger every day.

Writebol and Brantly are in an isolation unit at Emory University Hospital.

Doctors gave the two an experimental serum called ZMapp and were brought back to the United States.

Writebol's son Jeremy believes the protective care she's getting in Atlanta has played a big role in her recovery.

"The medical staff there has been incredible," he said. "They've been compassionate, professional, and that's been the key I think in helping mom recover."

Jeremy's father David Writebol is in quarantine at an RV park in Charlotte to make sure he doesn't have the deadly virus.

David Writebol spoke through Skype about his wife's recovery.

The last time he saw her in person she was getting on a plane to Atlanta, but he said the two have talked to each other, and he said every time he calls her she sounds better.

An Iowa drug developer said it has enough doses of a possible Ebola vaccine to launch an initial round of human testing.

Newlink Genetics Corporation said the vaccine has been 100 percent effective in preventing Ebola in primates.

Meanwhile, the last known doses of that experimental drug ZMapp that was given to Nancy Writebol and Brantly are now in Liberia.

Health officials said their biggest challenge is deciding who will get the drug.

It's already been announced that two doctors will receive it but it's unclear who else will have it.

The California company that makes ZMapp said it will take months to build up even a modest supply.

President Barack Obama has told the leaders of Liberia and Sierra Leone that the U.S. is committed to working to contain the Ebola outbreak in West Africa.

The president also offered condolences Thursday from Martha's Vineyard for the nearly 1,100 people killed by the virus.

WSOC