The CDC has fielded Ebola questions about 650 people, with 61 (9%) tested for the disease.
Several early vaccine trials are under way, and another American is airlifted home.
Ebola cases have now reached 17,145, and deaths total 6,070.
Foreign governments and aid groups need to show more flexibility, MSF leader says.
Strong international support is still needed, including treatment units, a top WHO official said.
Study results showed a good immune response at a high dose.
The WHO says Sierra Leone is likely to soon surpass Liberia's outbreak numbers.
Details from WHO on cases linked to an ill imam from Guinea who sought treatment in Mali.
The small biotech and the drug giant announced an agreement today.
Ban Ki-moon and other world leaders urged nations to continue aid for West Africa's Ebola outbreak region.
