GENEVA, April 29 (Reuters) - The World Health Organisation is set to increase its pandemic flu alert level to 5 -- its second-highest level -- within hours, WHO sources said on Wednesday. "Things are moving fast," one source said.
Another said the WHO was likely to increase the alert by one step, from 4 to 5, in response to the spreading swine flu virus, saying: "I don't think it will be 6."
According to the WHO's pandemic flu response guidelines, a phase 5 alert is called when there is human-to-human spread of virus in at least two countries in one region.
"While most countries will not be affected at this stage, the declaration of Phase 5 is a strong signal that a pandemic is imminent and that the time to finalise the organisation, communication and implementation of the planned mitigation measures is short," the document reads.
The move by WHO Director-General Margaret Chan to nudge higher the panedemic level -- which is set to occur without another formal emergency committee meeting -- follows intensive consultations with experts and analysis of the spreading virus within and from Mexico, sources said.
The change in level would put pharmaceutical companies and governments on alert about the need to start manufacturing enough antiviral drugs and accelerate efforts to create a vaccine to fight the swine flu strain, they said.
An announcement on the pandemic alert level is expected to be held at the WHO's Geneva headquarters around 2000 GMT. (Reporting by Laura MacInnis and Stephanie Nebehay)