FILE – In this Oct. 16, 2014, file photo, a healthcare worker dons protective gear before entering an Ebola treatment center in Freetown, Sierra Leone. In a letter published online Wednesday, Dec. 24. 2014, by the New England Journal of Medicine, doctors report that the Ebola death rate seems to have fallen even though there are no specific medicines or vaccines to fight the virus. (AP Photo/Michael Duff, File)