LONDON (AP) — The World Health Organization says millions of doses of two experimental Ebola vaccines could be ready in 2015 and five more experimental vaccines will start being tested in March.

Still, the agency warned it's not clear whether any of these will work against the deadly virus that has already killed over 4,800 people this year.

Dr. Marie-Paule Kieny from the agency told reporters there could be millions of doses of an Ebola vaccine in 2015 if early tests prove that the two leading candidates are safe and effective.

If the early trials hint at success, larger trials testing the vaccines in West Africa could begin as soon as December, Kieny said. She said five other possible Ebola vaccines should start being tested in March.