GENEVA (AP) — A top World Health Organization official says the hunt for an Ebola vaccine will produce data about whether they are safe by December — and they could be in experimental field use by January.

Dr Marie Paule Kieny, an assistant director general for WHO, says clinical trials planned or underway in Europe, Africa and the U.S. are being accompanied by a push among governments for immediate "real-world use" of an approved Ebola vaccine.

She told reporters Tuesday in Geneva that, if the vaccines are deemed safe, tens of thousands of doses would be used in a West African trial in January.

WHO spokeswoman Fadela Chaib also promises a thorough public audit of the agency's early missteps in responding to the Ebola outbreak that has already killed over 4,500 people.