Ebola vaccines 'being fast-tracked'
Two experimental vaccines are being fast tracked for use in the Ebola outbreak, the World Health Organization (WHO) says.
Safety trials are under way in the UK and US but will be expanded to 10 sites in Africa, Europe and North America.
Manufacturers are working on producing more doses, with the goal of "a very significant increase in scale during the first half of 2015", said the WHO.
Trials to assess whether experimental vaccines work could begin in January.
However, a number of challenges remain - including the ethics of running clinical trials and how to choose who receives the vaccines.
One vaccine - made by GlaxoSmithKline - is already being tested in a handful of healthy human volunteers. Another vaccine - developed by Canada - could start initial safety testing in the US this month.
The UN Agency said in a statement: "Both companies are working to augment their manufacturing capacity. The goal is a very significant increase in scale during the first half of 2015."
Rising death toll
The WHO said it expected to begin small-scale use of experimental Ebola vaccines in West Africa early next year. In the meantime, transfusions of survivors' blood may offer the best hope of treatment, it said.
Even if the experimental vaccines are shown to give protection in clinical trials, a significant number of doses will not be available until late in the first quarter of 2015, the health agency said in a statement after a two-day meeting of 70 experts.
"The next step is to make these vaccines available as soon as possible - and in sufficient quantities - to protect critical frontline workers and to make a difference in the epidemic's future evolution."
The death toll from the world's worst Ebola outbreak has reached 3,338 people out of 7,178 cases in West Africa.
The US Centers for Disease Control has warned that the number of infections could rise to up to 1.4 million people by early next year without a major global intervention to contain the virus.
Ebola virus disease (EVD)
- Symptoms include high fever, bleeding and central nervous system damage
- Spread by body fluids, such as blood and saliva
- Fatality rate can reach 90% - but current outbreak has mortality rate of about 70%
- Incubation period is two to 21 days
- There is no proven vaccine or cure
- Supportive care such as rehydrating patients who have diarrhoea and vomiting can help recovery
- Fruit bats, a delicacy for some West Africans, are considered to be virus's natural host.