Studies are underway to determine whether an Ebola vaccine is safe for humans, the World Health Organisation said on Monday.
"I think we have made very good progress but we are at the start of the journey. We are doing the very first studies in humans to find out if the vaccines are safe," the WHO's Dr David Wood told reporters in Pretoria.
"[If proven to be safe] we could then begin to use them on a larger scale in affected countries and some of the surrounding non-affected communities. These are new vaccines. We hope they will work."
He said from January, the vaccines could be used in the hard-hit West African countries. The international organisation had financial constraints, but was getting help from donors.
"We have to ensure that we co-ordinate all the partners coming on to assist. We have seen a tremendous response from the international community."
He said Ebola was a major public health problem.
"It is bigger than we have seen with Sars [Severe Acute Respiratory Syndrome]. The virus is more deadly than we saw with the influenza pandemic.
"The challenge is more complicated than it was with polio. This is the biggest public health challenge we, as the international community, has faced," said Wood.
Almost 5000 people have been killed by the virus, according to data from the World Health Organisation. It has recorded more than 13,000 cases, but admits the real number of infections and deaths could be much higher.