Dr Marie Paule Kieny, an assistant director general for WHO, said clinical trials that are either underway or planned in Europe, Africa and the US are expected to produce preliminary safety data on two vaccines by December.
If the vaccines are declared safe, she said they will be used in trials in West Africa beginning in January to test their effectiveness among tens of thousands, but not millions, of people.
The Ebola outbreak in West Africa has already killed over 4,500 people, mostly in Liberia, Guinea and Sierra Leone, since it emerged 10 months ago.
Experts have said the world could face 10,000 new cases of Ebola a week in two months if authorities don't take stronger steps to fight the deadly virus.