London - Johnson & Johnson 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 start 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 and a rival from NewLink and Merck, are already in clinical development, but the J&J vaccine offers a different approach since it involves two separate injections.
Brought under control
US-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 two million courses would be available in 2015. Previously, J&J expected more than one million courses this year.
It also now predicts it can make enough vaccine for five 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.
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.
More strategic option
Phase I trials are designed primarily to test safety but may also indicate whether vaccines produce a good immune response.
Shares in Bavarian Nordic, which received investment from J&J last year to accelerate production, rose 3.9% 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 $300m to buy Ebola shots.