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* Ebola emergency demands speed, more risk in vaccine tests
* Vaccines will be evaluated at same time as being deployed
* Issues of placebos and control groups need consideration
* WHO sees small-scale vaccine use in W. Africa by Jan 2015
By Kate Kelland, Health and Science Correspondent
LONDON, Sept 28 (Reuters) - Normally it takes years to provea new vaccine is both safe and effective before it can be usedin the field. But with hundreds of people dying a day in theworst ever outbreak of Ebola, there is no time to wait.
In an effort to save lives, health authorities aredetermined to roll out potential vaccines within months,dispensing with some of the usual testing, and raisingunprecedented ethical and practical questions.
"Nobody knows yet how we will do it. There are lots of toughreal-world deployment issues and nobody has the full answersyet," said Adrian Hill, who is conducting safety trials onhealthy volunteers of an experimental Ebola shot developed byGlaxoSmithKline.
Hill, a professor and director at the Jenner Institute atBritain's University of Oxford, says that if his results show noadverse side-effects, GSK's new shot could used in people inWest Africa by the end of this year.
Even if a drug is shown to be safe, it takes longer to proveit is effective - time that is simply not available when casesof Ebola infection are doubling every few weeks and projected bythe World Health Organization to reach 20,000 by November.
Among questions that scientists are grappling with: shouldan unproven vaccine be given to everybody, or just a few? Shouldit be offered to healthcare workers first? The young before theold? Should it be used first in Liberia where Ebola is spreadingfastest, or Guinea where it is closer to being under control?
Should people be told to assume it will protect them fromEbola? Or should they take all the protective measures theywould if they hadn't been vaccinated? And if so, how will anyoneknow whether the vaccine works?
GSK is one of several drug firms that have either started orannounced plans for human trials of candidate Ebola vaccines.Others include Johnson & Johnson, NewLink,Inovio Pharmaceuticals and Profectus Biosciences.
The WHO says it hopes to see small-scale use of the firstexperimental Ebola vaccines in the West Africa outbreak byJanuary next year.
It has convened vaccine specialists, epidemiologists,pharmaceutical companies and ethicists, for a meeting on Mondayand Tuesday to discuss the moral and practical issues.
"Normally safety is the absolutely paramount thing whenyou're developing a new vaccine, but this time we're going tohave to take more risks," said Brian Greenwood, a professor atthe London School of Hygiene and Tropical Medicine who will takepart in the WHO-led meeting.
"Quite how we do that, and what risks we take, hasn't reallybeen thought through yet. That's what people are trying tofigure out."
TWO THINGS AT THE SAME TIME
The chaos caused by the epidemic itself makes it even moredifficult to deploy and track use of a new vaccine, said Hill.
"You're trying to do two things at the same time: you'retrying to evaluate a vaccine and deploy it - when normally youwould evaluate the vaccine first, by doing a randomised doubleblind controlled trial, and then you'd deploy it if it was shownto be safe and effective."
Because Ebola virus is so deadly, those who receive a trialvaccine must be told to take all other precautions and protectthemselves fully. This could make it harder for researchers todecipher whether the protective clothing and safety protocols,or the new vaccine, is what kept them safe.
Normally researchers testing a vaccine would give somevolunteers a placebo, or dummy, to create a "control" group tocompare against those who get the real drug. That seemsunthinkable in a situation where disease with a death rate of upto 90 percent is raging through villages.
"Would it be ethical to do a trial where some people don'tget the vaccine because they are in the control group? Mostpeople think it wouldn't be - especially if you have reasonableevidence that the vaccine might work," said Hill.
Jeremy Farrar, an infectious diseases expert and director ofthe Wellcome Trust medical charity, said limited supplies of anycandidate vaccine could result in a form of natural controlgroup being formed anyway. Researchers can compare populationswhere the vaccine is available with those where it isn't.
GSK has said it is aiming to have 10,000 doses of itsexperimental shot by the end of the year, while Canada has given800 vials of the NewLink candidate vaccine to the WHO, expectedto yield at least 1,500 doses.
Most experts interviewed by Reuters favour the idea of thefirst doses going to frontline healthcare workers, since theirexposure to risk is so high. Researchers could then compareinfection rates among health workers who receive the vaccine tothose working in regions still waiting for it.
Peter Piot, a co-discoverer of the Ebola virus in 1976 andnow director of the London School of Hygiene and TropicalMedicine said that however complicated the ethics, reverting tothe traditional years-long process of testing vaccines, andwithholding them from West Africa until then, is not an option.
"It may be that without a vaccine, we can't really stop thisepidemic," he said. (Reporting by Kate Kelland; Editing by Peter Graff)
