* Guinea and Sierra Leone report 9 cases in past week
* GSK, NewLink vaccine trials may not produce efficacy data
* WHO hopes for framework deal on Ebola R&D by year-end
By Stephanie Nebehay
GENEVA, May 12 (Reuters) - With Ebola nearly stamped out inWest Africa, vaccine trials will probably fail to provide enoughuseful data on how well they protect people against the deadlyvirus, the World Health Organization (WHO) said on Tuesday.
Liberia was declared free from Ebola by the government andthe WHO on Saturday after 42 days without a new case of thevirus, which killed more than 4,700 people there during ayear-long epidemic.
Guinea reported seven cases in the week of May 4-10, whileSierra Leone had two, Dr. Marie-Paule Kieny, WHO AssistantDirector-General for Health Systems and Innovation, told a newsbriefing in Geneva.
"The best news is we are going to zero cases, there isabsolutely no doubt about that," she said.
But two experimental Ebola vaccines - developed byGlaxoSmithKline and jointly by Merck and NewLinkGenetics - being tested on volunteers may not yieldsufficient data on efficacy as case numbers fall, Kieny said.
"It is not clear whether it will be possible to have even ahint of efficacy from these two vaccines," she said, noting thatthey already had been proven safe.
"To have efficacy we must see if people are actuallyprotected, as the number of cases is going down it is not clearwhether there will be a strong robust answer to this question atthe end of epidemic," she said.
Two drugs - Zmapp made by Zmapp Pharmaceuticals and sIRNA byTekmira Pharmaceuticals - are also being tested and itis hoped that they will produce some limited results onefficacy, Kieny said.
The U.N. agency this week hosted a two-day experts' meetingon Ebola research and development after the world's largestepidemic that has killed more than 11,000 since December 2013.The aim is to draw up a plan to speedily develop vaccines anddrugs for use in clinical trials during any future outbreak ofany infectious disease.
Consultations will be held in coming months on issuesincluding developing protocols, data sharing and storingbiological material including the virus and blood serum ofpatients, Kieny said.
Asked when a framework deal on research and developmentcould be reached, she said: "Tentatively we try to go for theend of the year." (Editing by Louise Ireland)