LONDON (Reuters) - World Health Organization experts fighting the world's worst outbreak of Ebola hope for improved supplies of experimental treatments and progress with a vaccine by the end of the year.
That may come too late to put an end to the current epidemic, which is more likely to be stopped by standard infection control measures, but it offers hope for the next inevitable outbreak.
After ruling on Tuesday that it is ethical to offer unproven Ebola drugs to people infected or at risk in West Africa, the challenge is to secure enough doses to make a difference in an outbreak that has already claimed more than 1,000 lives.
An experimental drug called ZMapp from U.S. firm Mapp Biopharmaceutical appears to have had "a dramatic and very rapid effect" in the case of two U.S. doctors, WHO assistant director-general Marie-Paule Kieny told reporters.
However, the scant supplies of this drug are now effectively exhausted, after Liberia secured doses for two of its doctors. Spain's Health Ministry said a 75-year-old Spanish priest, the only other person known to have been given ZMapp, had died.
One of the deadliest diseases known to man, Ebola kills the vast majority of those infected. Its symptoms include internal and external bleeding, diarrhoea and vomiting.
Other drugs are also at an early stage of development, including a treatment from Tekmira Pharmaceuticals that was cleared last week by U.S. regulators for testing in infected patients.
None of these, however, is available in the quantities needed to make a dent in the West African epidemic - even if they work as well as hoped.
Still, the WHO is optimistic supplies can be ramped up by around the turn of the year, although the number of doses available will likely still remain insufficient to meet demand.
The United Nations agency also believes a vaccine can be fast-tracked for use in those most at risk, such as healthcare workers caring for patients, laboratory technicians and people burying the dead.
Kieny said two vaccine candidates were set to enter clinical trials in the coming weeks and there could be enough early-stage data to consider their emergency use by the end of 2014.
"We could have enough information, very preliminary, but maybe enough information on their safety in humans by the end of the year," she said. "There is a way to fast-track clinical trials."
The two vaccines due to enter the first phase of human testing have been developed by GlaxoSmithKline and Profectus Biosciences.
Normally, it takes many years to test a new drug or vaccine and determine it is safe for use, so the bar will be lowered significantly in the case of Ebola. That worries some experts.
"So far these therapies have been tested only in a handful of monkeys," said Kevin Donovan, director of the Center for Clinical Bioethics and a professor of paediatrics at Georgetown University, speaking on a panel convened on Tuesday by the O’Neill Institute for National and Global Health Law.
"We don’t know what harm they will do over the long term or even the short term. We owe it to the Ebola victims, current and potential, to get this right."
The decision to support the use of unproven treatments reflects the deadly nature of the disease and the need to close the research gap left by the pharmaceutical industry's failure to tackle a neglected tropical disease found in poor countries.
"The fact that there is currently no registered drug for Ebola is a market failure," Kieny said. "If it hadn't been for the investment of a few governments into the development of these drugs and vaccines, we would be nowhere."
There has been an outbreak of Ebola every few years since the virus was first discovered nearly 40 years ago in the forests of central Africa.
But it is only in the past 10 years or so that researchers - prompted in part by the perceived bioterror threat posed by Ebola - have started to look seriously at the disease, generating the current range of potential drugs and vaccines.
(Additional reporting by Kate Kelland, Stephanie Nebehay and Toni Clarke; editing by David Clarke)