* NewLink/Merck vaccine trial paused due to joint pains
* GAVI pledges up to $300 mln for 12 mln vaccine courses
* Further funding of up to $90 mln to help vaccine roll-out (Wraps stories on GAVI funding, NewLink vaccine trial, addsGAVI CEO comment)
By Ben Hirschler and Stephanie Nebehay
LONDON/GENEVA, Dec 11 (Reuters) - GAVI, the global vaccinesalliance, said on Thursday it was committing up to $300 millionto buy Ebola vaccines, as one experimental shot hit a snag in aSwiss clinical trial after some subjects reported joint pains.
Scientists are racing to develop Ebola vaccines in recordtime but many questions remain unanswered, as evidenced by adecision to pause Swiss tests of the experimental vaccine fromNewLink and Merck.
GAVI, which is funded by governments and the Bill & MelindaGates Foundation, said it was ready to begin procurement as soonas the World Health Organization (WHO) recommended a vaccine foruse.
The world's worst Ebola outbreak has killed more than 6,000people in West Africa and experts believe millions of doses ofvaccine may be needed both to help end the current epidemic andto contain future outbreaks.
Officials involved in the Swiss study said the volunteerswho had received the NewLink shot were all fine and the WHOplayed down the problem, pointing out that temporary suspensionswere not uncommon in clinical trials.
Researchers hope safe and effective vaccines will get agreen light as soon as next year, although there is stilluncertainty over how well they will work and how many doses areneeded.
Paying for vaccines is a challenge because the worstaffected countries of Sierra Leone, Liberia and Guinea are someof the world's poorest, providing little commercial incentivefor manufacturers.
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The money now earmarked by Geneva-based GAVI will helpbridge the gap and is expected to be enough to procure up to 12million courses of vaccine. WHO vaccine expert Marie-Paule Kienysaid the commitment was "fantastic".
In addition to helping in the current epidemic, the moneycould also be used to create stockpiles of Ebola vaccines,similar to those that exist for yellow fever, meningitis andcholera.
A further amount of up to $90 million will be made availablefrom GAVI's coffers to help affected countries introduce thevaccines and to rebuild their health systems.
GAVI, which was set up in 2000 with private and governmentdonor backing, has a track record of bulk-buying vaccinesupplies from manufacturers at a low price for the developingworld. Since 2000, around 440 million children have beenimmunised against a range of diseases through its programmes.
GAVI said its board had decided to prepare for procuringEbola vaccines while still awaiting a green light for the firstproduct, "in light of the seriousness of the situation and therisks associated with delays in making a vaccine available".
Two vaccines, one from NewLink and Merck and a rival shotfrom GlaxoSmithKline, are already undergoing human trials andthird one, made by Johnson & Johnson, is about to enterclinical testing.
"We've had individual discussions with all of themanufacturers and continue to work closely with them," GAVI'schief executive, Seth Berkley, told Reuters.
GAVI said it would meet the funding needs of the Ebolavaccine programme using a combination of existing and newfinancing. It also plans to join forces with other initiativesthat have already pledged funding to address the Ebola crisis.
(Reporting by Ben Hirschler; Editing by Pravin Char and GregMahlich)
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