J&J, Bavarian Nordic start clinical tests in Ebola vaccine race

* Initial Phase I clinical study starts in Britain

* First (Other OTC: FSTC - news) tests in Britain, more planned in U.S. and Africa

* J&J expects to have 2 million courses available in 2015

* Vaccine uses "prime-boost" approach involving two shots

* Bavarian Nordic (Other OTC: BVNKF - news) shares hit highest level in four years (Adds detail on Bavarian Nordic share price gains)

By Ben Hirschler

LONDON, Jan 6 (Reuters) - Johnson & Johnson (NYSE: JNJ - news) has started clinical trials of its experimental Ebola vaccine, which uses a booster from Denmark's Bavarian Nordic, making it the third such shot to enter human testing.

The initiation of the Phase I study in Britain, which had been expected about now, marks further progress in the race to develop a vaccine against a disease that has killed more than 8,000 people in West Africa since last year.

Two other experimental vaccines, one from GlaxoSmithKline (Swiss: GSK.SW - news) and a rival from NewLink and Merck (Other OTC: MKGAF - news) , are already in clinical development. However, the J&J vaccine offers a different approach, since it involves two separate injections.

U.S.-based J&J said on Tuesday it had produced enough vaccine to treat more than 400,000 people, which could be used in large-scale clinical trials by April, and a total of 2 million courses would be available in 2015. Previously, J&J expected more than 1 million courses this year.

It also now predicts it can make enough vaccine for 5 million treatments, if required, over a 12- to 18-month period.

Just how much Ebola vaccine will be needed depends on how quickly the epidemic in Liberia, Sierra Leone and Guinea is brought under control and declines. Currently, experts project demand at anywhere between 100,000 and 12 million doses.

"As long as there are still Ebola patients, there is the risk that it will continue to go around the region," Paul Stoffels, J&J's chief scientific officer, told reporters.

"Does it come too late? That's going to be answered when we are there. I don't think so."

'PRIME-BOOST'

The first volunteers have received initial injections in Oxford, where 72 healthy subjects will get different regimens involving various combinations of the vaccine components or a placebo.

Additional clinical studies are planned in the United States later this month and soon after in Africa, where volunteers will receive the vaccine in Kenya, Uganda and Tanzania.

Phase I trials are designed primarily to test safety but may also indicate whether vaccines produce a good immune response.

In all, some 300 subjects will be involved in Phase I testing, after which J&J hopes to move rapidly into larger studies, with final-stage Phase III trials planned for the second quarter of 2015.

The J&J and Bavarian vaccine uses a so-called "prime-boost" approach of giving a first shot to stimulate the immune system, followed by a second booster a few weeks later.

The GSK and NewLink vaccines have been tested initially as single shots, although there is growing debate as to whether two-stage vaccination might be a more strategic option, since it is likely to provide better protection. The downside is that it would make mass immunisation more complicated.

"What we are doing with prime-boost is going for maximal protection, as well as long-term protection," Stoffels said.

Importantly, tests have shown the J&J vaccine can be stored in a normal fridge for several months, rather than needing special freezing, which is difficult in rural Africa.

Shares (Dusseldorf: DI6.DU - news) in Bavarian Nordic, which received investment from J&J last year to accelerate production, rose 3.9 percent to their highest level in four years.

Although it is too early to say how much a vaccine might cost, the GAVI global vaccines alliance announced last month it was committing up to $300 million to buy Ebola shots.

(Editing by Louise Heavens and Pravin Char)