Two experimental Ebola vaccines, one from GlaxoSmithKline PLC and the other from biotech start-up NewLink Genetics Corp, "appear to be safe" part way through a clinical trial being conducted in Liberia, the U.S. National Institutes of Health said on Thursday. The two vaccines, each given in a single injection, are being tested for safety and efficacy on more than 600 people in Liberia in a mid-stage clinical trial sponsored by the National Institute of Allergy and Infectious Diseases, a branch of NIH.