Geneva - Trials of GlaxoSmithKline's experimental Ebola vaccine are likely to move to a second phase in February, later than previously suggested, after a meeting of national regulators said they needed more information.
The World Health Organization, which hosted a meeting of national regulatory authorities and ethics committees earlier this week, said they had thoroughly discussed all aspects of the proposed trials at the two-day meeting.
"Reviewing countries requested additional documentation from the manufacturer of the vaccine, GlaxoSmithKline, before authorization of the trials," the WHO said in a statement.
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Countries where the trials are planned, Cameroon, Ghana, Mali, Nigeria and Senegal, should receive and review the additional information by the end of January.
"If these steps are completed to the satisfaction of the national authorities, Phase II trials are likely to begin in February," the statement said.
The GSK vaccine is already undergoing Phase I trials, to check its safety in humans, in Switzerland, Britain, Mali and the United States, and is one of the two leading candidate vaccines for Ebola already undergoing tests.
The other vaccine, from NewLink Genetics is also still in Phase I trials. One of its trials, in Geneva, was suspended earlier this month after some patients complained of joint pains.
Johnson & Johnson plans to start clinical trials with a third vaccine shortly.
WHO officials have said they hope the unprecedented fast-track trials mean vaccines may be widely available around the middle of 2015, although they also hope the outbreak will be over by then. So far it has killed almost 7,000 people.
There are still many unresolved questions about the use of experimental vaccines, including whether subjects will need one or two injections.