A batch of experimental Ebola vaccine was today set to arrive in Switzerland from Canada, as researchers scramble to beat the deadly disease which has west Africa in its grip.
Marie-Paule Kieny, assistant director general of the World Health Organization, said the 800 vials would arrive by plane today and be transferred tomorrow to the Geneva University Hospital.
"It's better to keep them in a central pool than to start to spread them around and then to try to keep track of whether of all the mini-stocks we have have been kept at the right temperature," Kieny told reporters.
The vaccine must be stored at minus 80 degrees Celsius (-112 degrees Fahrenheit).
Canada has offered the Geneva-based WHO 800 vials -- each believed to contain about two doses -- of the rVSV vaccine developed at the National Microbiology Laboratory in Winnipeg.
Licenced by the Canadian government to US firm NewLink Genetics, rVSV is one of two experimental Ebola vaccines identified by the WHO as having shown promising results when tested on monkeys.
The other vaccine, ChAd3, is made by British company GlaxoSmithKline.
Kieny said both are "lead candidates" to fight Ebola, which has claimed more than 4,500 lives since the deadliest epidemic in history began in Guinea in December.
The overwhelming majority of the deaths and the 9,200 registered cases have been in Guinea, Liberia and Sierra Leone, but infections in countries including the United States and Spain have sparked fears of a wider spread.
Clinical trials of rVSV began in the United States in September, involving around 10 volunteers, said Kieny.
WHO-coordinated trials are set to begin in Geneva, in Germany, Gabon and Kenya, she added.
ChAd3, meanwhile, is being tested in the United States, Britain and Mali, with further trials poised to begin at the Vaud University Hospital in the Swiss city of Lausanne.
"We're waiting for the green light from Swissmedic before we get started," hospital spokesman Darcy Christen told AFP, referring to the national regulator.
Each Swiss trial is set to involve some 120 volunteers, with the combined 240 representing half the global total deployed to test the two drugs.
Kieny underlined that volunteers did not risk catching Ebola, since the vaccines contained just a single protein of the virus.
The trials are a key step because they will help determine both the safety of the vaccines and how great an immune response they are able to generate against Ebola.