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* Trial to test safety and immunogenicity of Ebola vaccine
* J&J working with Bavarian Nordic on prime-boost vaccine (Adds executive comment, link to story on Ebola nurse)
By Ben Hirschler
Oct 9 (Reuters) - Johnson & Johnson has begun aclinical trial of a two-shot Ebola vaccine in Sierra Leone,underlining its determination to push ahead with development,even as the epidemic fades out in West Africa.
The new study will investigate the experimental product'ssafety and its ability to provoke an immune response to thedisease, which the World Health Organization says has killedmore than 11,000 people in Guinea, Liberia and Sierra Leone.
Last week, for the first time since the Ebola outbreak wasdeclared in March 2014, there were no new confirmed cases of thedeadly disease in those countries, according to the U.N. agency.
Some survivors still suffer long-term effects from thevirus, which can persist in parts of the body after clearing theblood, including a Scottish nurse taken ill in Sierra Leone lastyear who is now back in hospital for more treatment.
The world already has one successful Ebola vaccine, withMerck and NewLink Genetics' product proving100-percent effective in a clinical study in Guinea in July.
But scientists and drug companies are continuing to researchthe potential of alternatives, since different kinds of vaccinesmay be better suited for different population groups.
"Both regulators and governments around the world haveencouraged us to continue," Paul Stoffels, J&J's chiefscientific officer, told Reuters.
Campaign groups such as Medecins Sans Frontieres are alsokeen to see multiple manufacturers in order to have competitionin the vaccine market to ensure lower prices and ample supply.
J&J, which is working with Bavarian Nordic indeveloping its vaccine, said on Friday that trial recruitmentwas underway in Sierra Leone and the first volunteers hadreceived their initial vaccine dose.
This is the first study conducted of the so-calledprime-boost vaccine regimen in a West African country affectedby the recent Ebola epidemic.
J&J's vaccine uses a combination of two components tostrengthen the immunity and make it last longer. The U.S.healthcare company said it had scaled up production to more than800,000 two-shot doses and had the capacity to produce 2 millionif needed.
Scientific experts believe the success of Merck andNewLink's vaccine suggests other products in trials should alsoprove effective.
Although these alternatives may not be tested in preventingEbola cases, given the current lack of disease, they could stillbe licensed and readied for use in future outbreaks based onhuman immune response results and data from non-human primateexperiments.
GlaxoSmithKline is also working on an Ebola vaccine. (Additional reporting by Supriya Kurane in Bengaluru; Editingby Anupama Dwivedi and Pravin Char)
