$300 mln pledged to buy Ebola vaccines as NewLink shot hits snag

* NewLink/Merck (Other OTC: MKGAF - news) 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, adds GAVI CEO comment)

By Ben Hirschler and Stephanie Nebehay

LONDON/GENEVA, Dec 11 (Reuters) - GAVI, the global vaccines alliance, said on Thursday it was committing up to $300 million to buy Ebola vaccines, as one experimental shot hit a snag in a Swiss clinical trial after some subjects reported joint pains.

Scientists are racing to develop Ebola vaccines in record time but many questions remain unanswered, as evidenced by a decision to pause Swiss tests of the experimental vaccine from NewLink and Merck.

GAVI, which is funded by governments and the Bill & Melinda Gates Foundation, said it was ready to begin procurement as soon as the World Health Organization (WHO) recommended a vaccine for use.

The world's worst Ebola outbreak has killed more than 6,000 people in West Africa and experts believe millions of doses of vaccine may be needed both to help end the current epidemic and to contain future outbreaks.

Officials involved in the Swiss study said the volunteers who had received the NewLink shot were all fine and the WHO played down the problem, pointing out that temporary suspensions were not uncommon in clinical trials.

Researchers hope safe and effective vaccines will get a green light as soon as next year, although there is still uncertainty over how well they will work and how many doses are needed.

Paying for vaccines is a challenge because the worst affected countries of Sierra Leone, Liberia and Guinea are some of the world's poorest, providing little commercial incentive for manufacturers.

STOCKPILES

The money now earmarked by Geneva-based GAVI will help bridge the gap and is expected to be enough to procure up to 12 million courses of vaccine. WHO vaccine expert Marie-Paule Kieny said the commitment was "fantastic".

In addition to helping in the current epidemic, the money could also be used to create stockpiles of Ebola vaccines, similar to those that exist for yellow fever, meningitis and cholera.

A further amount of up to $90 million will be made available from GAVI's coffers to help affected countries introduce the vaccines and to rebuild their health systems.

GAVI, which was set up in 2000 with private and government donor backing, has a track record of bulk-buying vaccine supplies from manufacturers at a low price for the developing world. Since 2000, around 440 million children have been immunised against a range of diseases through its programmes.

GAVI said its board had decided to prepare for procuring Ebola vaccines while still awaiting a green light for the first product, "in light of the seriousness of the situation and the risks associated with delays in making a vaccine available".

Two vaccines, one from NewLink and Merck and a rival shot from GlaxoSmithKline (Other OTC: GLAXF - news) , are already undergoing human trials and third one, made by Johnson & Johnson (NYSE: JNJ - news) , is about to enter clinical testing.

"We've had individual discussions with all of the manufacturers and continue to work closely with them," GAVI's chief executive, Seth Berkley, told Reuters.

GAVI said it would meet the funding needs of the Ebola vaccine programme using a combination of existing and new financing. It also plans to join forces with other initiatives that have already pledged funding to address the Ebola crisis.

(Reporting by Ben Hirschler; Editing by Pravin Char and Greg Mahlich)